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Transcript of Clean Fuels for Asia Ptl I,. ,,lo - World Bankdocuments.worldbank.org/.../pdf/multi-page.pdfNo. 305...
WO RLD BANK TECHNICAL PAPER NO. 377
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WORLD BANK TECHNICAL PAPER NO. 377
Clean Fuels for AsiaTechnical Options for Moving towardUnleaded Gasoline and Low-Sulfur Diesel
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WORLD BANK TECHNICAL PAPER NO. 377
Clean Fuels for AsiaTechnical Optionsfor Moving towardUnleaded Gasoline and Low-Sulfur Diesel
Michael WalshJitendra J. Shah
The World BankWashington, D.C.
Copyright © 1997The International Bank for Reconstructionand Development/THE WORLD BANK1818 H Street, N.W.Washington, D.C. 20433, U.S.A.
All rights reservedManufactured in the United States of AmericaFirst printing September 1997
Technical Papers are published to communicate the results of the Bank's work to the development community withthe least possible delay. The typescript of this paper therefore has not been prepared in accordance with the proce-dures appropriate to formal printed texts, and the World Bank accepts no responsibility for errors. Some sources citedin this paper may be informal documents that are not readily available.
The findings, interpretations, and conclusions expressed in this paper are entirely those of the author(s) andshould not be attributed in any manner to the World Bank, to its affiliated organizations, or to members of its Board ofExecutive Directors or the countries they represent. The World Bank does not guarantee the accuracy of the data in-cluded in this publication and accepts no responsibility whatsoever for any consequence of their use. The boundaries,colors, denominations, and other information shown on any map in this volume do not imply on the part of theWorld Bank Group any judgment on the legal status of any territory or the endorsement or acceptance of such bound-aries.
The material in this publication is copyrighted. Requests for permission to reproduce portions of it should be sentto the Office of the Publisher at the address shown in the copyright notice above. The World Bank encourages dissem-ination of its work and will normally give permission promptly and, when the reproduction is for noncommercialpurposes, without asking a fee. Permission to copy portions for classroom use is granted through the CopyrightClearance Center, Inc., Suite 910, 222 Rosewood Drive, Danvers, Massachusetts 01923, U.S.A.
Cover photo by Curt Carnemark, 1993, "Traffic in Mexico City."
ISSN: 0253-7494
Michael Walsh is a consultant in air quality management. Jitendra J. Shah is an environmental engineer in theWorld Bank's Asia Technical Environment Unit.
Library of Congress Cataloging-in-Publication Data
Walsh, Michael, 1943-Clean fuels for Asia: technical options for moving toward
unleaded gasoline and low-sulfur diesel / Michael Walsh, Jitendra J.Shah.
p. cm. - (World Bank technical paper; no. 377)Includes bibliographical references.ISBN 0-8213-4033-61. Motor fuel-Asia. 2. Tetraethyllead. I. Shah, Jitendra J.,
1952- . II. Title. III. Series.TP343.W28 1997363.738'7'095-dc2l 97-28968
CIP
CONTENTS
FoREwoRD .................. .... .............. ix
ACKNOWLEDGEMENTS ............................................................. Xi
ABBREVIATioNS, ACRONYMS, AND DATA NOTES ............................................... xiii
ABSTRACT ................................................................................ XV
EXECUTIVE SUMIMIARY ....................................... 1
CHAPTER 1 :INTRODUCTION .................................................................... 3BACKGROUND ....................................... 3
THE AIR QUALITY SITUATION IN ASIA ....................................... 3Bangkok, Thailand .......................................... 3Beijing, China .......................................... 4Ho Chi Minh City, Vietnam .......................................... 4Hong Kong, China .......................................... 4Kuala Lumpur, Malaysia .......................................... 4Manila, the Philippines .......................................... 4Jakarta, Indonesia .......................................... 4Mumbai, India .......................................... 5Kathmandu, Nepal .......................................... 5
CONCLUSIONS ............... : 5
ENDNOTES ............... 5
CHAPTER 2:GASOLINE ............... 7THE BENEFITS OF REDUCING LEAD IN GASOLINE ..................................... 7
Reduced Lead Health Risks ..................... 8Reduced Vehicle Maintenance ...................... 10Pollution Reduction by Emissions Converters .11
IMPLEMENTATION CONSTRAINTS ON UNLEADED GASOLINE ............................................. 12Refinery Modification Options to Produce Unleaded Gasoline .12Valve Seat Recession .14Potential Health Risks Associated with Lead Substitutes in Non-Catalytic Converter Vehicles. 14Strategies to Reduce or' Eliminate Health Risks Associated with Lead Substitutes .15
LUBRICANTS FOR TWO-STROKE ENGINES .21CONCLUSIONS REGARDING CLEANER GASOLINE .21
ENDNOTES .22
CHAPTER 3: DIESEL FUEL . ...... 25SULFUR ....... 25
v
CLEAN FUELS FOR AsIA: TECHNICAL OPTIONS FOR MO VING To wARDs UNLEADED GASOLrNE AND Lo W-SULFUR DIESEL vi
VOLATILITY ....................................................... 28AROMATIC HYDROCARBON CONTENT ....................................................... 28OTHER FUEL PROPERTIES ....................................................... 29FUEL ADDITIVES ....................................................... 29CONCLUSIONS REGARDING CLEAN DIESEL FUEL ................. ...................................... 29ENDNOTES ....................................................... 30
CHAPTER 4:ALTERNATIvE FuELs ....................................................... 31NATURAL GAS ....................................................... 32LIQUEFIED PETROLEUM GAS ....................................................... 33METHANOL ........................................................ 34ETHANOL ........................................................ 35BIODIESEL .................... .................................... 35HYDROGEN ...... . 36THE ECONOMICS OF ALTERNATIVE FUELS ..................................................... 36CLIMATE CHANGE ...................................................... 37ELECTRIC VEHICLES ...................................................... 39FACTORS INFLUENCING LARGE-SCALE USE OF ALTERNATIVE FUELS ................... .................... 41ENDNOTES ........................................................ 41
CHAPTER 5:IMPLEMENTING A CLEAN FUELS PROGRAM ...................................................... 43IMPROVING FUEL QUALITY ....................................................... 43VEHICLE FUEL REQUIREMENTS ....................................................... 43FUEL PUMP NOZZLE CHARACTERISTICS ....................................................... 43ADOPTING CLEAN FUEL TAx INCENTIVES ......................... .............................. 44VEHICLE POLLUTION CONTROL EFFORTS UNDERWAY IN ASIA ....................................................... 44
Bangkok, Thailand ........................................................... 45Singapore ........................................................... 47Hong Kong, China .......................................................... 49South Korea .......................................................... 49Taiwan (China) .......................................................... 50
COMPREHENSIVE PROGRAMS: THE UNITED STATES EXPERIENCE ...................................................... 52
CONCLUSIONS ........................................................ 53
ENDNOTES ........................................................ 54
CHAPTER 6:CONCLUSIONS AND RECOMMENDATIONS ............................................... 55CONCLUSIONS ........................................................ 55
RECOMMENDATIONS ........................................................ 56
APPENDix A: ADVERSE EFFECTS FROM VEHICLE-RELATED POLLUTION .............................. 57
APPEND1X B: CONTROLS ON GASOLINE-FUELED VEHICLES ............................................... 67
APPENDIX C: CoNTROLs ON DIESEL-FUELED VEHICLES ............................................... 77
APPENDIX D: INTERNATIONAL EMISSION AND FuELS STANDARDS ........................................ 91
vii
BoxEs2.1: What We Know About Lead Exposure, Past and Present .................. ........................ 92.2: Can Unleaded Gasoline be Used in Pre-Catalytic Converter Vehicles? .................... 132.3: Colorado's Success Story .................................................................. 152.4: The Effects of Oxygenated Gasoline: Wisconsin, Maine, and the U.S. Environmental
Protection Agency .................................................................. 172.5: Impact of Oxygenate Used ..................... ............................................. 203.1: Fuel Variables Found to Have a Significant Impact on Pollutant Emissions .......... 253.2: Options to Reduce the Sulfur Content of Diesel Fuel ...................... ......................... 27
FIGuREs2.1: Unleaded Gasoline Jigsaw Puzzle-Issues to Address, Pieces to Put Together ......... 72.2: Economic Benefits of Reducing Lead Exposure ....................................................... 10
2.3: Impact of Lead on Catalytic Converter-Equipped Cars ............................................ 122.4: The Environmental Costs of Catalytic Converter Cars Using Unleaded Gasoline
Versus Non-Catalytic Converter Cars Using Leaded Gasoline ................................... 133.1: Emissions from Buses in Finland ............................................. ..................... 274.1: Greenhouse Gas Emissions from Fuels .................................................................. 405.1: Inplementing a Clean Fuels Program .................................................................. 435.2: Elements of a Comprehensive Vehicle Pollution Control Strategy ........................... 445.3: Trends in Emissions from U.S. Cars (normalized to 1970 levels) ............ ................. 53
TABLES2.1: Environmental Residence Times For Various Pollutants .................. ........................ 82.2: Additional Savings from Leaded Versus Unleaded Gasoline .................................... 112.3: Cost Savings from Maintenance Reductions with Lead-free Gasoline (1980
Canadian cents per liter) .................................................................. 112.4: Component Control Costs and VOC Emissions Reductions ...................................... 213.1: Environmental Classifications for Sweden ............................................................... 264.1: Properties of Conventional and Alternative Fuels ............................. ....................... 314.2: Comparative Costs of Alternative Fuels (1987) ......................................................... 374.3: Costs of Conventional and Alternative Fuels in the United States ........................... 385.1: South Korea: Emissions Standards For New Gasoline and LPG Vehicles ............... 505.2: South Korea: Emissions Standards For New Diesel Vehicles ................................... 515.3: Emissions Trends In The United States (1 970-90): Passenger Cars (tons per year) 53
FOREWORD
Air pollution has become a serious issue in many policymakers to make informed choices amongAsian cities. A major cause is the expanding motor technical and financial options available forvehicle population-with growth rates as high designing a clean fuels program that couldas 23 percent in rapidly growing economies such ultimately improve Asian cities' air qualityas China. Policymakers in Asia are beginning to significantly.review options to deal with vehicular pollution The Metropolitan Environment Improvementreduction. Experience worldwide has shown that Program (MEIP) facilitated the preparation of thisthe use of clean fuels-low-lead or unleaded publication by providing the authors with finan-gasoline and low-sulfur diesel-is a cost-effec- cial support, background data, and links to Asiantive way of reducing vehicular emissions. cities participating in MEIP. We hope that this
The use of cleaner fuels in conjunction with report will be widely used by decisionmakers incatalytic converters would limit the total amount MEIP cities and in other cities throughout Asia.of emissions, thus reducing damage to human andecosystem health. Its use would also lead to lowercosts in terms of vehicle maintenance and effi-ciency for the individual owner.
This report describes strategies, incentives, andmethods to increase the use of clean fuels. It Maritta Koch- Weserprovides policymakers with a range of al- Chiefternatives that can be employed to develop a clean Asia Environment and Naturalfuel strategy. We hope this report will assist Resources Division
lx
ACKNOWLEDGEMENTS
We would like to acknowledge the groups and vice and guidance of Maritta Koch-Weser, Divi-individuals who contributed to this report and the sion Chief, and David Williams, MEIP Programpromotion of clean fuel options in Asia. Core Manager. Internal reviews and comments werefunding was provided by the United Nations provided by Asif Faiz, P. Illangovan, MasamiDevelopment Programme, the Australian Con- Kojima, Victor Loksha, Magda Lovei, Tanvisultant Trust Funds, the Belgian Consultant Trust Nagpal, Anil Somani, Gautam Surhicd Cor VanFunds, the Netherlands Consultant Trust Funds, Der Sterren, Walter Vergara, Ronald Waas, L.the Royal Norwegian Ministry of Foreign Af- Wij itilleke, and Yaacov Ziv. External peer review-fairs, and the Norwegian Consultant Trust Funds. ers were Charles Freed (U.S. Environmental Pro-Inputs to this report were provided by Katsunori tectionAgency),BernieJames (Natural ResourcesSuzuki and Sonia Kapoor of the World Bank, Canada), Gregory Rideout (Environment Canada),and host governments and city administrations. and Tazio Yamada (consultant). The list of inter-
The authors of this report are Michael P. Walsh national emissions and fuel standards contained(consultant) and Jitendra Shah (World Bank). in Appendix D was provided by Gregory Rideout
In the World Bank's Asia Environment and (EnvironmentCanada). AnniceBrownwasrespon-Natural Resources Division, the Clean Fuels re- sible for accuracy and editing Julia Lutz providedport was managed by Jitendra Shah, under the ad- editorial support and designed the report's layout.
xi
ABBREVIATIONS, ACRONYMS, AND
DATA NOTES
AQG Air Quality Guideline NMHC non-methane hydrocarbonsAQIS Air Quality Information System NO, nitrogen oxidesAQMS Air Quality Management System NO2 nitrogen dioxideBHP brake horsepower OECD Organization for EconomicBaP benzo(a)pryene Cooperation and DevelopmentBTU British Thermal Unit PAHs polynuclear aromatic hydrocarbonsCARB California Air Resources Board Pb leadCDC Centers for Disease Control (U.S.) PM particulate matterCNG compressed natural gas PM,o particulate matter 10 microns or lessCO carbon monoxide ppm particles per millionDDT dichloro diphenyl trichloro ethane PNA polycyclic nuclear aromaticsETBE ethyl tertiary butyl ether RFG refomulated gasolineEGR exhaust gas recirculation RVP Reid vapor pressureEU European Union SO2 sulfur dioxideEV Electric vehicle SOF soluble organic fractionFCC fluid catalytic cracking SPM suspended particulate matterFTP Federal Test Procedure (U.S.) TBA tertiary butyl alcoholGDP gross domestic product TSP total suspended particulateGEMS Global Environmental Monitoring TWC three-way catalyst
System UNDP United Nations DevelopmentHC hydrocarbons ProgramIPCC Intergovernmental Panel on Climate URBAIR Urban Air Quality Management
Change Strategy in Asia (World Bank)LPG liquefied petroleum gas USAID U.S. Agency for IntemationalAg micrograms (10-6 grams) Developmentmg miligrams (10-3 grams) USEPA U.S. Environmental Protectiong/m3 micrograms per cubic meter AgencyMCPA methylchlorophenoxyacetic acid VOCs volatile organic compoundsMEIP Metropolitan Environmental WHO World Health Organization
Improvement Program (World Bank) 1 gallon (U.S.) = 3.785 litersMMT metylclopentadieny manganese 1 mile = 1.609 kilometers
tricarbonylMON motor octane number Note: Except as indicated, "dollars" refersMTBE methyl tertiary-butyl ether to 1995 U.S. dollars.NGO non-governmental organization Except as indicated, all boxes,NGV natural gas vehicle figures, and tables were compiled forNH3 ammonia this report by the authors.
xiii
ABSTRACT
Motor vehicles have brought increased mobility of lead from gasoline. In conjunction with cata-and access to employment for greater numbers of lytic converters, unleaded gasoline use leads topeople in Asia in the last decade. However, these reductions in major pollutants such as hydrocar-benefits have been partially offset by excess ur- bons, carbon monoxide, and nitrogen oxides. Un-ban airpollution and damageto the ecosystem and leaded gasoline should be made cheaper thanhuman health. This report focuses on the abate- leaded gasoline at the pump. In addition to thisment of vehicular pollution through the use of priority step, it is also crucial that other cleancleaner fuels, such as unleaded gasoline and low- fuels be promoted. For example, the sulfur con-sulfur diesel Itaimstoprovidedecisionmakerswith tent of diesel fuel should be reduced to controla methodology for making informed choices con- emissions of sulfur and particulates. Alternativecerningtheproductionanduseofcleanertransport clean fuels such as natural gas and liquefied pe-fuels for motor vehicles. Transport demand man- troleum gas should also be promoted.agement inspectionandmaintenance, and advance- Poorly maintained cars are responsiblefor a dis-ment of vehicle technology are the other compo- proportionate amount of emissions. Regular in-nents of a vehicle pollution prevention program. spection and maintenance of vehicles results in a
This report recommends that governments substantialreductioninparticulate,volatileorganicadopt a strategy for the progressive elimination compounds, and carbon monoxide emissions.
xv
EXECUTIVE SUMMARY
Motor vehicles have brought increased mobility, the pump. The benefits of eliminating lead out-and access to employment for greater numbers of weigh the costs.people in Asia in the last decade. However, these 2. Reduce the sulfur content of diesel fuels.benefits have been partially offset by excess ur- Reducing sulfur in diesel has the dual advan-ban air pollution and damage to human and eco- tage of lowering sulfur dioxide and particu-system health. Asian countries can no longer ig- late matter emissions, and can be a cost-ef-nore air pollution, and must begin to design fective option: Lowering the fuel density iscomprehensive air quality management systems. also an effective means of reducing fine par-These systems should encompass not only trans- ticulate emissions. Other diesel fuel proper-port policy but also large industries, small enter- ties such as volatility, aromatic content, andprises, and domestic sources of pollution. additives may have a positive or negative ef-
This report focuses on the abatement of fect on emissions. In addition to the adoptionvehicular pollution through the use of cleaner of mandatory limits on sulfur, tax policies canfuels such as unleaded gasoline and low-sulfur be very effective in encouraging the use ofdiesel. The pollutants like lead and particulate low-sulfur diesel.matter (from diesel and other vehicles) are 3. Encourage the use of alternative fuels. Al-targeted because they have been identified as the ternative fuels that have been proven cost-ef-largest contributors to health damage in urban fective should be promoted through policiesareas. This report aims to provide decisionmakers that encourage substitution. Conservation ofwith a methodology for making informed choices oil products, energy security, and climatecon-cerning the production and use of cleaner change or global warming are additional rea-transport fuels for motor vehicles. Transport sons for encouraging the use of alternativesdemand management, inspection and main- to conventional fuels.tenance, and advanced vehicle technology are the In addition to these three important steps, theother components of a vehicle pollution regular inspection and maintenance of vehiclesprevention program. should be encouraged. Poorly maintained cars are
The report recommends the following priori- responsible for a disproportionate amount of ve-tized policy options: hicle emissions. Semi-annual inspection and main-1. Adopt a strategy for the progressive elimi- tenance of vehicles results in a substantial reduc-
nation of lead from gasoline. Using unleaded tion in particulates, volatile organic compounds,gasoline and catalytic converters also leads to and carbon monoxide emissions. Emissions re-reductions in other major pollutants such as duction can occur simultaneously with improvedhydrocarbons, carbon monoxide, and nitrogen fuel economy and diminished need for repairs.oxides. Unleaded gasoline use should be en- Asia's vehicle population is projected to con-couraged through clean vehicle standards and tinue growing well into the next century. If noby making it cheaper than leaded gasoline at action is taken now, air quality is bound to dete-
1
CLEAN FUFELS FOR AsiA: TECHINCAL OP2ONS FOR MoviNG TowARDs UNIL.&DEL GASOuINE AND LOw-SULFUR DIESEL 2
riorate, exacting a high toll on human health and policymakers some valuable tools and sugges-possibly undermining many economic develop- tions for confronting the worsening air pollutionment gains. Based on lessons learned in other situation now, and ensuring a cleaner environ-parts of the world, this report offers Asia's ment in the future.
CHAPTER 1:INTRODUCTION
This report provides the methodology for improv- ides (NO.), and toxic substances such as fine par-ing air quality in large Asian cities through the ticles and lead, as well as contributing to second-use of clean fuels. This study is directed to ary by-products such as ozone.1 Reducing vehicu-decisionmakers whose policies have a direct im- lar pollution usually requires a comprehensivepact on the production and use of cleaner trans- strategy encompassing the following elements:port fuels. The objective of this report is to pro- * automobile demand management (incentivesvide a technical overview of the challenges and to reduce automobile use such as road tolls,opportunities for lowering vehicle emissions by parking restrictions, area licensing schemes,means of fuel modifications or substitutions. Is- mass transit availability, etc.);sues receiving particular attention are reducing * inspection and maintenance;and removing lead in gasoline and reducing * advanced vehicle technology; andsulfur in diesel fuel. * clean fuels.
This report focuses primarily on clean fuels. Itstartswith abriefsummaryoftheairpollutionprob-
BACKGROUND lem in selected Asian cities, followed by the chal-lenges and opportunities for lowering vehicle pol-
In 1995, the global motor vehicle population, in- lutionthroughgreateruseofcleanoralternativefuels.cluding passenger cars, trucks, buses, motorcycles, The remainder of the report explores some of theand three-wheeledvehicles (tuk-tuks orrickshaws) pollution control efforts underway in the region.exceeded 700 million for the first time in history.While most ofthese vehicles remain concentratedin the highly industrialized Organization for Eco- THE A1:R QUALITY SITUATION IN AsIAnomic Cooperation and Development (OECD)countries, an increasing number of urbanized ar- Over the course of the past two decades, there haseas in developing countries, especially in Asia, now been an explosive growth in many Asian coun-contain many motorized vehicles. Cities includ- tries' motor vehicle populations. As a result, se-ing Bangkok, Jakarta, and Seoul have some of the rious air pollution exposure problems caused bymost congested roads in the world. While these vehicle emissions are emerging. The section be-vehicles have brought many advantages, includ- low takes a brief look at nine Asian cities.ing increased mobility and flexibility for millionsof people and more jobs, and enhanced many Bangkok, Thailandquality-of-life aspects, the benefits have been par-tially offset by excess pollution and adverse ef- Eleven years of air quality monitoring indicatefects on human health and the environment. that the air pollutants of greatest concern in
Motorvehicles emit large quantities of carbon Bangkok are suspended particulate matter (SPM),monoxide (CO), hydrocarbons (HC), nitrogen ox- especially respirable particulate matter (PM10)2,
3
CLEAN FuELs FOR Asi4: TECHANC4L OPToAs FOR MOVING TowARDs UNLEADED GASOLINE AJYD Low-SULFUR DIESPL 4
CO, and lead, caused mostly by the transport sec- estimated to be responsible for approximately 50tor. Current SPM levels in Bangkok's air, espe- percent of PM10 emissions. Using the methodol-cially alongcongestedroads, far exceed Thailand's ogy developed by the California Air Resourcesprimary ambient SPM air quality standard. In Board, the Hong Kong Environmental Protec-1993, curbside 24-hour average concentrations tion Agency estimates that particulates from die-exceeded this standard on 143 out of 277 mea- sel vehicles alone cause approximately 290 pre-surement days. Mobile sources continue to be the mature deaths from lung cancer each year.Bangkok population's biggest source of exposure.
Kuala Lumpur, MalaysiaBeijing, China
Based on available 1992 data, it was concludedIn spite of a relatively small vehicle population, thatthe air pollution problem is relatively seriousair pollution problems caused by motor vehicles in comparison with accepted air quality guide-have started to emerge in major Chinese cities, lines.3 Annual and daily PMIO averages regularlyespecially Beijing. The number of automobiles exceeded guidelines, as did CO and ozone. Fol-in Beijing is almost 10 percent of the total in all low-up studies in 1994 continued to show seri-of China (19 million), and many Chinese-made ous problems, as particulates routinely exceededvehicles still use 20-year old designs, resulting guideline limits and appeared to be worsening.in CO and HC emissions rates that are 10-20 NO2 and particulate matter were the most perva-times the levels emitted by modem engines. Ac- sive air pollutants, and motor vehicles were againcording to an air quality survey, motor vehicles found to be the main source of air pollution.contribute about half of the total CO, HC, andNOX emissions coming from all pollutant sources. Manila, the PhilippinesLead is another pollutant of concern; concentra-tions of lead in Beijing are 1-1.5 p.g/m3, and have InMetro-Manila, airqualitydataareavailable, andreached 14-25 gg/m3 in extreme cases. measured concentrations of PMIO routinely ex-
ceeded acceptable levels by a factor of more thanHo Chi Minh City, Vietnam three. Measured total suspended particulates (TSP)
exceeded acceptable levels by even larger percent-Although available air quality dataare limited, the ages. Lead concentrations also exceeded Govern-Institute of Hygiene and Public Health conducted ment standards.4 Monitoring indicates that botha monitoring study in 1993. Results showed that CO and NO2 occasionally exceed standards. Mea-particulates, or dust, are a very serious problem surement for sulfur dioxide (SO2 ) and total oxi-at present, and that CO and nitrogen dioxide dants indicated concentrations, at present, were(NO 2 ) also exceeded current Vietnamese stan- within acceptable standards. Motor vehicles weredards. The study demonstrated that although found to contribute over 40 percent of PM10.5
many sources certainly contribute to these prob-lems, vehicle emissions seem to dominate. Jakarta, Indonesia
Hong Kong, China During the ten-year period between 1981 and1991, Jakarta's population doubled; there was
Particulates are Hong Kong's most serious pol- also a tremendous rise in the number of vehicles,lution problem at present, and motor vehicles are from approximately 900,000 to 1,700,000, mak-
5 CH4APER 1: INlRODUCI7ON
ing Jakarta's growth rate one of the highest in motor vehicles in the past decade, which can bedeveloping countries. These changes are reflected seen in increases in the use of gasoline (150 per-in the city's poor air quality. Overall, traffic and cent), motor diesel (175 percent), kerosene (250industry are Jakarta's main sources of air pollu- percent), and fuel oil (580 percent) duringtion. TSP emissions are estimated at 96,733 tons 1980-93. Air pollution measurements show thatper year, PMI0 emissions total 41,369 tons per particulate pollution is the most significant prob-year, and NOX emissions are calculated at 43,031 lem in the Kathmandu Valley. Total TSP emis-tons per year. Annual TSP averages in the most sions per year amount to 16,500 tons. PM10 emis-polluted areas are 5-6 times the national air qual- sions are 4,700 tons per year. WHO guidelinesity guidelineand varied from 180 to 600 .ig/m3. for TSP and PMIO are often substantially ex-Motor vehicles were found to contribute 40 per- ceeded. TSP concentrations have been measuredcent or more to PM10.6 at above 800 1Lg/m3 (WHO TSP guidelines are
150-230 jig/M3). Visibility in the Valley has beenMumbai, India reduced substantially, which has impacted tour-
ism, one of Nepal's major sources of revenue.8
Greater Mumbai's population grew 38 percent Motor vehicles and scattered small brick manu-between 1971 and 1981, and another 20 percent facturers were found to be the largest source ofby 1991, reaching 9.9 million. The expansion of human exposure to air pollution.industry, increased production, and a 103 percentincrease in the number of motor vehicles has ledto a severe air pollution problem. Diesel trucks CONCLUSIONSand three-wheel vehicles contribute significantlyto air pollution. The annual TSP concentration As the above examples illustrate, many majorincreased from 180 ,ug/m3to approximately 270 Asian cities' current air quality levels alreadyjig/m3 between 1981 and 1990, an increase of reflect serious air pollution, with the transportalmost 50 percent. Total annual emissions of TSP sector contributing about 50 percent of PMIO.and PM, are estimated at 32,000 and 16,000 tons, Because the vehicle populations in most ofrespectively, per year. World Health Organiza- these cities continue to grow, often at rates ex-tion (WHO) air quality guidelines and national ceeding 10 percent per year, future air pollutionguidelines for TSP are frequently exceeded in problems will be even more serious unless ag-Mumbai. Of the population, 97 percent lives in gressive control efforts are undertaken. Fortu-areas where the WHO guideline is exceeded. nately, several countries in the region have de-Measures to reduce air pollution in Mumbai must veloped significant pollution control efforts,focus on the most important source-traffic- which are the subject of chapter 5.which contributes about 50 percent of PM10 .7
Kathmandu, Nepal ENDNOTES
Kathmandu Valley's population grew 44 percent 1. See appendix A for a detailed review of ad-between 1980 and 1990. In 1992, its population verse health affects associated with vehicularwas estimated at 1,060,000, of which 54 percent air pollution.was urban. The growth in population has been 2. PMI0 refers to particles in the size range of 10accompanied by a doubling in the number of microns or less. All of these particles are con-
CL4N FUms FOR ASI: TECHMCAL OPnoms FOR MOnNG TowARDs UNEADsD GAsoUAE AAD Low-SusFuR DiEsE 6
sidered respirable and therefore, from the pub- 5. Nagpal, Tanvi and Jitendra J. Shah, eds. 1997.lic health perspective, more important than Urban Air Quality Management Strategy inlarger particles. Asia: Metro Manila Report. World Bank
3. Japan International Cooperation Agency. Technical Paper No. 380. Washington, D.C.August 1993. "Air Quality Management Study 6. Nagpal, Tanvi and Jitendra J. Shah, eds. 1997.For Kelang Valley Region." Urban Air Quality Management Strategy in
4. The World Health Organization is sponsoring Asia: Jakarta Report. World Bank Technicala study regarding "The Impact Of Vehicular Paper No. 379. Washington, D.C.Emissions On Vulnerable Populations In Metro 7. Nagpal, Tanvi and Jitendra J. Shah, eds. 1997.Manila"; preliminary results indicate that 10 Urban Air Quality Management Strategy inpercent of school children (ages 6-14 years) Asia: Greater Mumbai Report. World Bankhave blood lead levels of 20 micrograms per Technical Paper No. 381. Washington, D.C.deciliter or higher. This is twice the level of 8. Nagpal, Tanvi and Jitendra J. Shah, eds. 1997.concern identified in the umbilical cord study. Urban Air Quality Management Strategy inAll ofthe street childvendors tested (ages 6-15) Asia: Kathmandu Valley Report. World Bankhad blood lead levels above 10 and many had Technical Paper No. 378. Washington, D.C.levels over 30, an alarming statistic.
CHAPTER 2:
GASOLINE
In most developing countries, gasoline consump- duce overall vehicle emissions. It will concludetion contributes substantially to overall vehicle with recommendations for decisionmakers onemissions. The most critical issue is whether or how to advance the use of cleaner gasoline.not to reduce or eliminate the use of lead-basedadditives. Not many years ago, almost all gaso-line used contained lead (as an octane booster), THE BENEFITS OF REDUCING LEAD INoften in concentrations greater than 0.4 grams GASOLNEper liter. Since the early 1970s, there has been asteady movement toward reducing lead in gaso- In many ways, lead is an extremely useful mate-line and, increasingly, completely eliminating rial. It resists corrosion and weathering, is plen-lead. Countries as diverse as Austria, Brazil, Ja- tiful in readily accessible areas, and is easilypan, Thailand, and the United States have com- melted down for use. Because of these charac-pletely eliminated lead from gasoline (see appen- teristics, it has been widely used by humans fordix D for a list ofinternational automo-tive emissions and fuel Figure 21: Unleaded Gasoline Jigsaw Puzzle-Issues to Address,standards). In addition, Pieces to Put Together(in 1996) over 85 per-cent of all new carsworldwide will require Rcfiner Valve
the exclusive use of un- Public Modifications Rcession in
leaded gasoline to pro- Information O ) ( Vehi
tect their emissionscontrol systems (cata-lytic converters). Thissection of the report GFaelPricing ,lasied Distribktionwill review the reasons Policy G l Workfor the shift to unleadedgasoline (figure 2.1);address some of the ar-guments against the useof unleaded gasoline; New Vehicle
and finally summarize Octane Substitutes Emissions HealthEffectsStandardsother fuel characteris- -__________
tics used in reformu-lated gasolines to re-
7
CV FUELs FOR ASIw. TECHmC4L OP27OvS FOR MOrVNG TOWARDS UM.EADED GASOLINE AND Low-Su uFuR DIESEL 8
centuries, in plumbing, printing, hunting, build- more strongly to gasoline lead than to lead in theing, and more recently as electrical insulation, ra- air alone."2 Because of this close relationship,diationshielding,andinpaintsandbatteries.Lead's reducing gasoline's lead has been demonstratedinertness, which makes it a useful material, how- in the United States to significantly reduce healthever, may also lead to its relatively long environ- risks in urban areas. For example, based on datamental residence time, as indicated in table 2.1.1 collected in more than 60 U. S. cities by the Cen-
ters for Disease Control (CDC) (commonlyReduced Lead Health Risks known as the NHANES II study), the decline in
mean blood lead levels, computed by six-monthGasoline lead affects human health through sev- intervals, almost parallels the declining amountseral media, the most important of which is air. It of lead used in gasoline during 1976-80.3is generally recognized that over 90 percent of After a careful review of the NHANES II data,atmospheric lead concentrations in most urban CDC's Center For Environmental Health (Dr.areas using leaded gasoline are attributable to Vernon Houk) explained,gasoline lead emissions. Beyond this, however, 'ThisreductionwasreaL Itwas not due to chance,gasoline lead increases the amount of lead in- laboratory error, nor sampling of age, sex, race,gested through the digestive system. This is es- urban versus rural areas, income levels, or geo-pecially true of children who not only ingest this graphic regions. Themostsignificantenvironmen-lead through the normal food chain, but also play tal change during this time was the reduced amountin lead-contaminated streets and yards. It is not ofleadused in the production of gasoline ... (Thesesurprising that "both average blood lead levels data) clearly demonstrates that as we have re-and cases of lead poisoning in children correlate moved lead from gasoline, we have also removed
lead from ourselves and our children."4
In the past, leaded gasoline was cited as thereason for elevated blood lead levels every sum-
Table 2. 1: Environmental Residence mer in the United States. This was correlated toTimes For Various Pollutants increased use of automobiles during those
months. Automotive emissions are also the rea-Pollutant Situation Time Remaining (%) son why lead levels in the front yards of urban
2,4,5-T soil several 50 homes are two to three times greater than in the(herbicide) weeks back yards.MCPA soil several 50 In Europe, the Joint Research Center in Ispra,(herbicide) days Italy, completed a study designed to determine(hersicide)mdays the relationship between gasoline lead and hu-
(pesticide) man uptake.' The study replaced standard gaso-line lead with a variant having a different isoto-
Oil sea water 45 70 pic ratio, in order to follow the pathway ofweeks gasoline lead through the northern Italian region
Lead soil 70-200 90 of Piedmont, where the study was conducted. Theyears study reached the following conclusions:
Source: Royal Commission on Environmental 1. Gasoline lead is responsible for about 90 per-Pollution. April 1983. "Lead in the cent of airborne lead in Turin and about 60Environment' Ninth Report. percent of airborne lead in rural areas.
9 CHAPTER 2: GASOLINE
Box 2.1: What We Know About Lead Exposure, Past and PresentBecause of lead's growing number of uses and long also impair overall fuel efficiency by not allowing theresidence time, human lead exposure has been increas- use of up-to-date motor vehicle technology and moreing for many generations, and will probably continue efficient pollution reduction techniques.4'5 In adults,to accumulate in the future. It is now estimated that blood lead is related to blood pressure increase and tomodem man's lead exposure is 100 times greater than cardiovascular disease, particularly strokes, heart at-background or "natural" levels.I Studies of annual arc- tacks, and premature death. The monetary benefits oftic ice layers in Greenland also indicate the rise in lead reducing adult illnesses would be substantial and wouldlevels over the earth's surface. At this point in history, probably outweigh the costs.6
lead has been dispersed so widely that "it is doubtful In spite of these concerns, much of the discussionwhether any part of the earth's surface or any form of regarding removal of lead from gasoline has focusedlife remains uncontaminated by anthropogenic lead."2 almost exclusively on costs and difficulties, and littleMore recent evidence continues to show "unambigu- on the benefits. The purpose of this section (and appen-ous evidence of the gasoline-related sources of lead in dix A) is to summarize some of thesepotentialbenefits.aged Greenland snow and ice.""
One of the modem world's major uses of lead is in Sources:gasoline. In 1921 it was discovered that the additionof lead to gasoline raised octane levels. This was de- 1. Granjean, Phillippe, M.D., Odense University. Maysirable because higher octane gasolines allow higher 1983. "Health Aspects of Gasoline Lead Additives,"compression ratio engines with concomitant improve- presented at Conference Lead In Petrol.ments in thermal efficiency and fuel economy. How- 2. Royal Commission on Environmental Pollution, Aprilever, the addition of lead to gasoline caused a whole 1983. "Lead In The Enviromnent," Ninth Reportseries of problems for automotive designers, includ- 3. Lobinski, Boutron, Candelone, Hong, Szpunar-ing troublesome combustion chamber deposits onpis- Lobinska, and Adams. 1994. "Present Century Snowtons, spark plugs, and valves, and increased piston ring Core Record of Organolead Pollution in Greenland,"wear and blow-by rates. Environmental Science and Technology:
More importantly, as discussed in appendix A, evi- (28)1467-1471.dence has been accumulating that children in cities 4. Lovei, Magda. August 1996. "Phasing Out Leadare suffering adverse health consequences when lead from Gasoline: World-Wide Experience and Policyadded to gasoline is emitted from vehicles. In addi- Implications," Environment Department Paper No.tion, lead deposits within engine combustion cham- 40, The World Bank: Washington, DC.bers lead to higher emissions of hydrocarbons, which 5. Faiz, Asif, Christopher S. Weaver, and Michaeldirectly and indirectly harm health and well-being. Walsh. 1996. "Air Pollution from Motor Vehicles:Furthermore, the use of lead precludes the use of cata- Standards and Technologies for Controlling Emis-lytic converters, that have been demonstrated to sub- sions." The World Bank: Washington, DC.stantially reduce hydrocarbons and other noxious gases 6. Wijetilleke, Kariyawasam. "Cost-Benefit Analysisin vehicle exhaust. Ironically, by precluding the use of Mitigating Transport Pollution." World Bankof these advanced technologies, leaded gasoline may draft report.
2. Gasoline lead seems to contribute the finest Dr. Facchetti, noted that the relationship betweenairborne lead particles. airborne lead and blood lead is relatively equal
3. The percent of gasoline-supplied lead in blood between Europe and the United States-an in-was 24-27 percent in Turin; 12-21 percent in crease of 1 microgram of lead per cubic meter ofthe nearby countryside; and 11-19 percent in ambient lead results in an increase of about 1-2the remotest countryside. micrograms per milliliter of blood lead.6 Further-Assessing the study, the institute's director, more, the Ispra experiment probably underesti-
CLEANv FUELs FOR ASIA: TEcHImcAL OP.7novs FOR MOVING TowARDs UNLEADED GAsOu[NE AND LOW -SULFUR DIESEL 10
mated the overall impact of gasoline lead on ists money by reducing the need to continuouslyblood lead because: replace spark plugs, mufflers, and other automo-1. Only about 90 percent of the local gasoline bile hardware exposed to gasoline and its com-
contained the test isotope. bustion products.' Lead scavengers are highly2. The study only measured local effects and corrosive and reactive; several surveys conducted
could not account for lead emitted and blown when leaded gasoline was widely available in thein from vehicles from other areas. United States and Canada demonstrated that mo-
3. When the experiment ended, gasoline-related torists using lead-free gasoline spent much lessblood levels had not yet reached equilibrium; on exhaust system and ignition servicing than mo-blood lead levels were still rising. torists using leaded gasoline.9 As a general prin-In adults, blood lead is related to blood pres- cipal, spark plug change intervals are usually
sure increases arnd cardiovascular disease, par- doubled by the use of unleaded gasoline, and atticularly strokes, heart attacks, and premature leastoneexhaustsystem and exhaust silencer (muf-death. The monetary benefits of reducing adult fler) replacement during the life of a motor ve-illnesses affected by airborne lead would be sub- hicleis eliminated. Lead-free gasoline is also linkedstantial, and would probably outweigh the costs tocostadvantagesregardingcarburetorservicing,of reducing the lead (figure 2.2).7 but this has been more difficult to quantify.
Another significant advantage associated withReduced Vehicle Maintenance lead-freegasoline is alengthened interval between
oil changes. Unleadedfuel has been demonstratedOne of the greatest benefits of eliminating lead to significantly reduce engine rusting and pistonfrom gasoline would be the reduction in health ring wear, and to a lesser degree, sludge and var-risks, but there would be additional benefits. For nish deposits and cam and lifter wear."' Becauseexample, lead-free gasoline would save motor- of this, oil change intervals in U.S. cars using un-
Figure 2.2: Economic Benefits of Reducing Lead Exposure
7000 - US$6,937
6000 U * * Infant Mortality5000 * l M Earnings Loss
o 4000 --3000 1 microgram/ deciliter
E- 2000 reduction, for one year's0> 2000 . . > | cohort of U.S. children,: 1000 j- equals US$5,307 per IQ poin
Source: Schwartz, Joel. 1983. "Health Effects of Gasoline Lead Emissions," USEPA, Washington, DC.
11 CHAPZXR 2: GASsoam
leaded fuel have become at least twice as long ashad previously been the case. Intervals of 10,000 Table 2.2: Additional Savings frommiles are not uncommon in new cars. Increased Leaded Versus Unleaded Gasolineoil change intervals cannot be attributed solely tolead removal (as is indicated by some increases in Process Leaded Unleadedvehicles using leaded gasoline), but lead removal Gasoline Gasolineappears to be a contributing factor. This is signifi- spark plug changes every year ever othercant not only because of the reduced cost to the yearmotorist, but also because of oil savings over the oil &ilter changes twice per once pervehicle's life, and the reduced pollution poten- year yeartial of the used oil. Perhaps more significant inreducing engine wear are the additive packages muffler replacements twice per 5 once perthat are added to unleaded fuel for lubricity, asyrs yearwell as changes in valve ring material (table 2.2). exhaust pipe replacements once per 5 none
The Environment Protection Agency (Canada) yrsstudied-reductions in maintenance costs attribut- Source: Moule, M.G. 1981. "The Benefits of Unleadedable to lead-free and unleaded gasoline. An Aus- Petrol," Institution on Engineers Transportationtralian review reported those results and found Conferencethem to be significant.1 Expressed as 1980 Ca-nadian cents per liter, the results of the studiesconcluded (table 2.3): Table 2.3: Cost Savings from
A car consuming 10 liters of unleaded fuel Maintenance Reductions with Lead-freeper 100 kilometers would experience mainte- Gasoline (1980 Canadian cents per liter)nance savings averaging about Can$3 8 per year,or Can$0.024 per liter of gasoline.12 Company Year Cost
Savings
Pollution Reduction by Emissions Converters Wagner (Amerian Oil Co.) 1971 1.4Gray &Azhari (Amercan Oil Co.) 1972 2.1
The U.S. Environmental Protection Agency Pahnke & Bettoney (DuPont) 1972 0.3(USEPA) studied the impact of leaded gasoline Adams (Ethyl Corp.) 1972 0.4on the performance of catalytic converters in1984.1' Twenty-nine in-use automobiles with Environment Canada 1979 1.2three-way catalytic converter systems were Source: Mowle, M.G. 1981. "The Benefits of Unleadedmisfueled with leaded gasoline in order to quan- Petrol," Institution of Engineers Transportatontify the emissions effects. (For a review of con- Conference.trols on gasoline-fueled vehicles, see appendix
B.) The vehicles used between four and twelvetanks of leaded gasoline (average lead content results of the program indicated that vehicle emis-1.0 grams per gallon). Four different test pro- sions are primarily affected by the amount of leadgrams were conducted, with different misfueling passing through the engine, and secondarily byrates and mileage accumulation schedules. The the rate of misfueling. In addition, lead in gaso-U.S. Federal Test Procedure (FTP) and several line not only affects the performance of the cata-short tests were conducted at various stages. The lyst but poisons it as well.
CLE.p.. FuELs FOR .42X: RCTMCAL OPuONS FOR AdIoY TowAws UM1DE G.S4amw .wN Low-SuuR DlEsFL 12
Based on the data collected, it was possible to IMPLEMENTATION CONSTRAINTS ONdevelop quantitative relationships between lead UNLEADED GASOLINEconsumption and HC, CO, and NOX emissions.Emissions levels for each of the 29 vehicles in- While the problems (health, economic, and en-volved in the USEPA program were normalized vironmental) associated with leaded gasolineto the levels which existed prior to any lead con- have been outlined above, it is important to alsotamination,'4 then plotted as a function of the to- outline potential hazards associated with unleadedtal amount of lead consumed. Normalization gasoline. Lead is added to gasoline because it ismade it possible to eliminate the influence of dif- a low-cost octane enhancer. If lead is not addedferent emissions standards. Regression equations to gasoline the refinery must either modify itswere then derived, relating HC, CO, and NOX processes to raise the octane level, or add alter-emissions respectively to the grams of lead con- native octane-enhancing additives, such as MMT,sumed by each vehicle (figure 2.3). ethanol MTBE, or ETBE.
As figure 2.3 indicates, FTP emissions of HC,CO, andNOX generally increasedsteadilywith con- Refinery Modification Options to Producetinued misfueling. HC emissions increased the Unleaded Gasolinemost rapidly on a percentage basis, followed byGO, and to a lesser extent, NO.. Reasonably good Refinery investments are generally capital-inten-correlations exist for the relationship between to- sive. The selection of technology to mitigate ortal lead consumed and emissions increases of each eliminate adverse environmental impacts by fuelpollutant, especially for HC, one of the pollut- reformulation is a complex process. Addressingants most affected. In the case of HC, approxi- specific clean fuel reformulation characteristicsmately 90 percent of the variability in emissions for each petroleum product (if addressed indi-can be explained by the lead exposure. vidually) may add substantially to costs, com-
Figure 2.4 comparesthe environmental costof catalytic convertercars using unleaded Figure 2.3: Impact of Lead on Catalytic Converer-Equipped Carsgasoline versus non- Normalized Emissionscatalytic converter cars 6burning leaded gaso- v NMHC v
line. The initial extra 5 * co v
cost of the catalytic 4 * NOx WVconverter can be recov- -ered within four years 3 *or less, depending on 2the actual emissions re-duction and mainte- 1
nance, and associated 0health impact and other 0 50 100 160 200cost assumptions for Grams Of Lead
the non-catalyst cars. Source: Michael, R Bruce. 'Misfueling Emissions ofThree-Way Catalyst Vehicles," 1984.
13 CHAPIR 2: GASOLINE
pared to an integratedprogram encompassing Figure 2.4: The Environmental Costs of Catalytic Converter Carsgasoline, diesel oil, and Using Unleaded Gasoline Versus Non-Catalytic Converter Carsresidual fuel oil. Other Using Leaded Gasoline.externalities may re-quire a program to be B0-.fragmented. 700.Catalytic Converter
Modifications andadditions to existing 3 00 .. YJthoutCatalytic Cornerter refineries to meet emerg- 40,
ing environmentally-friendly gasoline speci- S 200 1 5 0 5 r 0 5 *
fications could range 1 -over a wide spectrum:* introducingchanges 0 1 2 3 4 5 6 7 S 9 10 11 12 13 14 15
in operating condi-tions in naphtha re- Source: Authors' estimates.
formers (althoughone may wish tolimit the total amount of aromatics); lead levels, the preferred option was to increase
* changingthecrudeoilsuppliedto the refinery; the octane number by more severe reforming of* modifying the fractionation process; and naphtha to compensate for octane lost by elimi-
introducing new processing facilities such as nating lead. This increased the aromatics (espe-alkylation, isomerization, fluid catalytic crack- cially benzene) concentrations in gasoline. As theing, hydrocracking, and oxygenate production adverse health impacts of these hydrocarbonsfacilities. began to be known, USEPA imposed limitationsThe strategy used will need to be project-spe- resulting in the need for additional investments
cific and linked to desired objectives. A multi- to eliminate the problem created by more severelypronged program including reduced or eliminated reformulated naphtha.lead, limited benzene and aromatic levels, Reid The costs of even a modest gasoline reformu-vapor pressure control, and front-end octane im- lation program will be substantial. Therefore, itprovement could include all of the process op- is important to tailor the program to meet speci-tions listed above. A more modest program might fied environmental objectives. Furthermore, careneed only a few of those options. needs to be taken to ensure that investments do
Aside from removinglead, limiting aromaticsand benzene must be fac- Box 2.2: Can Unleaded Gasoline be Used inPre-Catalytictored into any gasoline Converter Vehicles?reformulation program.As seen in the United Yes, for most cars:States in the early 1970s, * Valve recession has not been observed under real-world conditions.when restrictions were * Lead substitutes (sodium, sulfur) available if needed.first imposed on gasoline * No other impediments identified.
CLEAN FuEIS FOR ASA: TECHNICAL OPIIONS FOR MOVNG TOwARDS UMNEADED GAsoLJNE AND Low-SbuFUR DIESEL 14
not produce undesirable secondary problems, and high-octane hydrocarbons such as benzene, tolu-do not become a constraint to expanding the re- ene, xylene, other aromatics, and olefins. Paraf-formulation program as gasoline markets expand. fin isomerization is also used to convert straight-
chain paraffins (relatively low-octane) toValve Seat Recession higher-octane branched paraffins. Alkylation
combines light olefins with isobutane to produceAs engine technology advanced during the leaded higher molecular weight branched paraffins.gasoline era, motor vehicle designers used lead's Motor fuel alkylate is the gasoline blending com-friction-reducing properties to serve as a lubri- ponent of choice: it contains no sulfur, no ben-cant between exhaust valves and their seats, en- zene, and negligible olefins and aromatics; withabling them to use a lower-grade metal for the a high blending octane and a low RVP. Increasedvalve seats. Leaded fuel shielded the valve seats quantities of light hydrocarbons, such as butane,from excessive wear, or valve seat recession, are also blended. Use of high-octane oxygenatedwhich can occur at high speeds in engines with- blending agents such as ethanol, methanol (without hardened valve seats. This protective func- co-solvent alcohols), and especially methyl ter-tion is the reason why USEPA limited gasoline tiary-butyl ether (MTBE), as well as other agents,lead content to 0.1 grams per gallon, rather than has increased greatly. In addition, the antiknockbanning its use entirely in 1985. However, the additive methylcyclopentadienyl manganeseactual incidence of valve seat recession is mi- tricarbonyl (MMT) is permitted in leaded andnuscule;"5 the only vehicles even appearing to be unleaded gasoline in the United States, and avulnerable travel consistently at very high loads health testing program is being developed to as-and speeds, and even in these vehicles, additives sess MMT' s and oxygenates' effects on health.other than lead have been shown to protect valve MMT is also permitted in both leaded and un-seats. There is no technical argument to retain leaded fuel in Canada.16
any lead in gasoline, if the refining capacity ex- Some of these solutions have created or ag-ists to provide the required octane in some other gravated environmental problems of their own.manner. For example, although Thailand com- For example, the increased use of benzene andpletely eliminated the sale of leaded fuel on Janu- other aromatics (which tend to increase benzeneary 1, 1996, there has been no evidence of valve emissions in the exhaust) have led to concern overrecession problems in existing vehicles. However, human exposure to benzene, which is carcino-it should be noted that in some countries (e.g., genic. The xylenes, other alkyl aromatics, andthose that manufacture cars without catalytic con- olefins producemuch more ozonethan mostotherverters, or that import cars from these manufac- hydrocarbons. Increaseduseof lighlt hydrocarbonsturers) lack of information concerning these is- in gasoline produces a higher Reid vapor pres-sues may pose a constraint to lead phaseout. sure (RVP), and increased evaporative emissions.
Most of these lead substitutes are not a seri-Potential Health Risks Associated with Lead ous concern if the switch to lead-free gasoline isSubstitutes in Non-Catalytic Converter Vehicles combined with the introduction of catalytic con-
verters. As indicated in appendix B, catalyticRefineries use a number of techniques to replace converters tend to be especially effective on manythe octane formerly contributed by lead. As noted of the more reactive or toxic hydrocarbons. How-above, increased catalytic cracking and reform- ever, in order to maximize the health benefits ofing are used to increase the concentrations of unleaded gasoline use in vehicles without cata-
15 CH.4PIER 2: GASOLINE
lytic converters, it is prudent to assure that ac- Ion (since 1985). In Europe, the maximum leadceptable alternatives are used. content of leaded gasoline is 0.15 gramsperliter.
Strategies to Reduce or Elininate Health Lead substitutes. Blending small percentages ofRisks Associated with Lead,Substitutes oxygenated compounds such as ethanol, metha-
nol, tertiary butyl alcohol (TBA), and MTBE andLow-lead gasoline as a transition fuel. Vehicles other ethers with gasoline has the effect of im-equipped with catalytic converters require un- proving the antiknock performance. Thus, theleaded gasoline so as not to destroy the converter amount of lead can be reduced or even elimi-with lead deposits. Vehicles without catalytic nated, without substituting potentially hazardousconverters can use unleaded gasoline but do not aromatic compounds.require it. Because reducing or eliminating gaso- Exhaust HC and CO emissions are reducedline lead is desirable for public health reasons, by the use of oxygenates, but NO xemissions mayone transition strategy that may be used while be increased slightly by leaner air-fuel mixtures.catalytic converter technology is being phased The U.S. Auto/Oil study recently tested the ef-in is to continue to market fuel with a minimal fects of adding 10 percent ethanol (3.5 percentlead content. oxygen by weight) and adding 15 percent MTBE
The octane boost from lead does not increase (2.7 percent oxygen by weight) to industry-av-linearly with lead concentration. The first 0.1 erage gasoline. For newer gasoline vehicles, thegram per liter of lead additive gives the greatest ethanol addition results showed a net decrease inoctane boost, and subsequent lead concentration non-methane hydrocarbons (NMHC) (5.9 per-increases give progressively smaller returns. This cent) and CO (13.4 percent), and a net increasemeans that two units of low-lead gasoline will in NO emissions (5.1 percent). The MTBE ad-produce lower lead emissions than one unit of dition results showed net decreases in NMHC (7.0high-lead gasoline of the same octane value, in a percent) and CO (9.3 percent), and a net increasemotor vehicle without a catalytic converter. Ifoctane capacity is limited, the quickest and mosteconomical way to reduce lead emissions maybe to reduce the gasoline supply's lead content Box 2.3: Colorado's Success Storyby as much as possible, rather than encouragingnon-catalytic converter-equipped cars to use un- The success of one program in Colorado (Unitedleaded fuel. This also helps to reserve supplies States) lead the U.S. Congress to mandate the use ofof unleaded gasoline (often feasible to produce oxygenated fuels (minimum 2.7 percent oxygen by
and distribute onyilmweight) in areas with serious wintertime CO prob-and distribute only in limited quantities) for cata- lems. Colorado initiated a program to require thelytic converter-equipped vehicles truly requiring addition of oxygenates to gasoline during winterit. Reducing the permitted lead content will also months when high ambient CO tends to occur. Thereduce the refining cost difference between mandatory oxygenrequirementforthe winter of 1988leaded and unleaded gasoline. If this is reflected (January-March) was 1.5 percent by weight, equiva-in retail prices, it will reduce the temptation for lent to about 8 percent MTBE. For the followingowners of catalytic converter-equipped vehicles years, the minimum oxygen content required was 2
percent by weight (equivalent to 11 percent VTBE).to misfuel with leaded gasoline. In the United These oxygen requirements were estimated to re-States, as noted earlier, the lead content of leaded duce CO exhaust emissions by 24-34 percent ingasoline has been limited to 0.1 grams per gal- vehicles already fitted with 3-way catalyst systems.
CLEAN FUELs FOR AsIA: TECHINCAL OnIONS FOR MOwNG TowAw.s UATzADED GASOLINE AND Low-S uFuR DIESEL 1 6
in NO emissions (3.6 percent). unregulated emissions. As part of a comprehen-xAmong oxygenates, ethers have lower blend- sive policy to reduce vehicle emissions, fuel re-
ing RVP than alcohols such as ethanol. Reduc- formulation could not only offset any increaseding the RVP of gasoline is one of the most cost- risks associated with introducing unleaded gaso-effective means of controlling HC emissions. line, but would complement the elimination ofCorrosion, phase separation on contact with wa- lead health risks. This would result in an overallter, and materials compatibility, other problems reduction of the toxic and ozone-forming poten-sometimes experienced with alcohol fuels, are tial of gasoline, and gasoline vehicle emissions.much less serious for ethers. For this reason, The potential for reformulating gasoline toMTBE and other ethers are strongly preferred as reduce pollutant emissions attracted considerableoxygenated blending agents by many fuel mar- attention in the United States, as pressure to shiftketers as well as for air-quality purposes. The to alternative fuels increased during the middlecosts of using ethers are also relatively moderate and late 1980s. This effort led to a major(approximately US$0.0 1-0.03 per liter at present cooperative research program between the oil andprices), so these substitutes can be a cost-effec- automobile industries. A similar effort in Europetive approach as well. followed during the early 1990s. Consequently,
To summarize, it is possible to substitute cer- a great deal has been learned about the potentialtain oxygenates in place of lead to produce un- to modify gasolines to significantly improve airleaded gasoline with maximum health benefits, quality. An additional advantage of fuelno lead, and no increase in other toxic com- reformulation is that it can reduce emissions frompounds. The case of Hong Kong, China (chapter all vehicles on the road, much as reducing lead5) demonstrates how unleaded gasoline can have ingasoline reduqes lead emissions from allvirtually the same aromatic content as leaded ve lcles.. '
gasoline, in part due to the use of oxygenates."7 The most significant potential emissions re-ductions that have been identified for gasoline
Health effects of MTBE. During the winters of reformulation have been achieved by making the1993 and 1994, a number of U.S. cities using following changes:oxygenated gasoline (as required by the 1990 * reducing volatility (to reduce evaporativeClean Air Act) reported cases of people suffer- emissions);ing from severe nausea, headaches, and other * reducing sulfur (to improve catalyst effi-symptoms. These cases were apparently linked ciency); andto the exposure to MTBE fumes or its combus- * adding oxygenated blend stocks (with a cor-tion derivatives. Following an intense public out- responding reduction in the high-octane aro-cry over the use of oxygenated gasoline in Mil- matic hydrocarbons which might otherwise bewaukee, Wisconsin, the state ordered a study of required).the health effects. The first phase has been com-pleted and the results to date do not support health Lowering volatility: potential benefits of improv-linkages with MTBE (box 2.4). ing various fuel parameters. Fuel volatility, as
measured by Reid vapor pressure (RVP), has aReformulated gasoline. Beyond substituting marked effect on evaporative emissions fromoxygenates that are less hazardous than lead, ad- gasoline vehicles with and without evaporativeditional gasoline modifications are possible. Re- emissions controls. Tests on vehicles withoutformulating gasoline reduces both regulated and evaporative emissions controls showed that in-
17 CHAPIER 2: GAsouNE
Box 2.4: The Effects of Oxygenated Gasoline: Wisconsin, Maine, and the U.S.Environmental Protection Agency
Wisconsin dents may have actually been due to colds or influ-* Ambient air monitoring in Milwaukee detected re- enza andnotRFG exposure; and therefore, otherfac-
formulated gasoline components. tors (e.g., viruses) may have influenced these ad-* Levels found were not unusually high and did not verse health effects.
exceed any health guidelines.* As in other studies, refueling a vehicle at a station Awareness of Reformulated Fuels
without stage II vapor recovery equipment resulted - Individuals in Milwaukee and greater Wisconsinin the highest exposure potential. who purchased RFG since November 1994 were
* Symptom prevalence in Milwaukee differed signifi- more likely to report specific symptoms than indi-cantly from both Chicago, Illinois, and the remain- viduals who had not purchased RFG since that dateder of Wisconsin. or were not aware of the type of gasoline they pur-
* In Milwaukee, people were more likely to report chased.unusual symptoms if they had had a cold or influ- * Since all gasoline purchased in Milwaukee wasenza, smoked cigarettes, or were aware of purchas- RFG, this suggests that knowledge of RFG, includ-ing RFG since November 1994. ing possible awareness of potential negative effects
* Symptom prevalence in Chicago (an area required of reformulated gasoline in Milwaukee and greaterto use RFG) was no different from that in greater Wisconsin, may have heightened the perception ofWisconsin (an area not required to use RFG). current health status and led to the assumption that
* This finding suggests that factors other than RFG any health symptoms experienced were unusual anduse significantly contributed to differences in symp- attributable to gasoline exposure.tom prevalence between Milwaukee and the other * This fmding is consistent with those in chamber teststwo areas studied. where individuals noted RFG had a different odor
* Individual symptoms and symptom patterns attrib- than traditional gasoline.uted to exposure to reformulated gasoline are non-specific, and similarto those experienced with com- Mainemon acute and chronic illnesses, such as colds, * Complaints reported in January-February 1995.influenza, and allergies. Typical symptoms reported were non-specific diz-
* Since every symptom was statistically more preva- ziness, lightheadedness, and respiratory symptoms.lent in Milwaukee than the other two areas (includ- * After an organized effort to ban the use of RFG wasing symptoms not associated with gasoline or chenii- initiated, the Maine Bureau of Health began receiv-cal solvent exposure), it suggests that other factors, ing unsolicited health surveys from York County,in addition to the introduction of RFG in that city, Maine. These health surveys were distributed by ancontributed to the survey responses. organization called "Oxy Busters." Subsequently,
the Bureau of Health received 48 surveys reportingRespiratory F'actors complaints linked to RFG, including odors, head-
* All three sample areas experienced the same rate of aches, breathing problems, sneezing, and other con-winter colds and influenza during the 1994-95 sea- cems. These surveys were tabulated and analyzed.son (55-60 percent). In response to published newspaper reports, the Bu-
* Havinghad acold orinfluenzawas the strongestpre- reau of Health also received several letters and nu-dictorofunusual symptoms attributedto gasolineuse merous telephone calls describing health problems.amongtheMilwaukeerespondents,butwasnotapre- To date, the vast majority of complaints have origi-dictor for such symptoms in Chicago or greater Wis- nated in York County.consin.
* The most plausible explanation for this finding isthat many symptoms reported by Milwaukee resi- (Continued next page)
CLEv FVIs FOR ASIA: TECHNICAL OP2ONS FOR MO VING TowARDs UNLEADED GASOLINE AND LOW-SULFUR DIESEL 18
Box 2.4: The Effects of Oxygenated Gasoline: Wisconsin, Maine, and the U.S.Environmental Protection Agency (continued)* This report was written to provide not only an over- formation to recommend against banning MTBE
view and evaluation of specific health concerns that RFG because both regular gasoline and ozone rep-have been linked to RFG, but also to place those resent significant public health hazards and envi-concerns specifically in context of Maine. To ac- ronmental risks.complish this, the health effects of gasoline with- * In fact, the use of MTBE RFG, in combination without 11 percent MTBE, and the health effects of other Stage II vapor recovery mechanisms at service sta-air toxins in Maine and the nation were weighed. tions, could be expected to achieve some positive
* In addition, the introduction of MTBE RFG, during health impacts. Significant NO.reductions are re-the late fall and early winter, occurred when expo- quired in RFG Stage II beginning in the year 2000.sure to other factors having adverse health impacts MTBE health effects have been reviewed by the(influenza and cold viruses, indoor air toxins, se- National Academy of Science and Health Effectsvere cold, and dry air) would be maximized. Institute in 1996, with generally similar findings.
* Headaches, skin irritation, and respiratory problemssuch as sneezing and shortness of breath all in- The U.S. Environmental Protection Agencycreased during this season. * Gasoline vapors and vehicle exhaust contain vola-
* The healthproblems attributed to RFG are very simi- tile organic compounds (VOCs) and nitrogen ox-lar to those raised by citizens in other parts of the ides (NO.) that react in the atmosphere in the pres-United States. ence of sunlight and heat to produce ozone, a major
* The investigation of health effects in Alaska ap- component of smog.pears to be inconclusive and has not been confinned * Motorvehicles also release toxic emissions, includingby similar studies done in New Jersey and New benzene, a known human carcinogen. RFG containsYork. less ingredients contributing to these harmful forms
* The presence of MTBE in groundwater was raised of air pollution Consequently, RFGreduces the U.S.as a significant environmental health and contamnina- public's exposure to ozone and certain air toxins.tion issue by persons questioning the use of MTBE RFG contains oxygen additives (oxygenates) suchRFG in Maine. as MTBE and ethanol. Although used in some fuels
* Review of the available literature, evaluation of in- as octane enhancers since the late 1970s, oxygen-statesourcesofraformation, anddiscussionswithother ates were first widely used in a oxygenated fuel pro-states, particularly Colorado, confmns the fact that gram begun in 1992 in 39 urban areas.MTBE has been found in groundwater in Maine and * This program was required by the 1990 Clean Airelsewhere inthe United States (see theUSEPAstudy). Act in cities with high CO pollution.
* MTBE has been detected in Maine groundwater (and * Oxygenates increase the combustion efficiency ofoccasionally in drinking water) for about a decade, gasoline, thereby reducing motor vehicle CO emis-at levels exceeding the current health-based stan- sions. CO can also affect healthy individuals bydard of 50 parts per billion. At present, MTBE in impairing physical capacity, visual perception,drinking water is not thought to pose a significant manual dexterity, learning functions, and ability tohealth hazard. perform complex tasks.
* Furthermore, contamination levels should be de- To date, research suggests that the oxygenates usedcreasing as a problem with leaking underground in reformulated gasoline pose no greater a healthstorage tanks is addressed. risk than the standard gasoline RFG replaces,
* Becausepeoplehave suggested the presently unsub- while helping decrease vehicle emissions. Studiesstantiated possibility of significant airbome MTBE are ongoing, however.contamination of groundwater, increased surveil-lance for MTBE in groundwater is reconimended. Source: Summary of USEPA, January 19, 1995,
* The Health Effects Task Force identified a suffi- "Health Risk Perspectives on Fuel Oxygenates Withcient quantity of available high-quality research in- MTBE."
19 CHAP7ER 2: GAsoLINE
creasing the fuel RVP from 9 pounds per square proximately US$0.0038 per liter, assuming crudeinch (psi) (62 kilopascals) to approximately 12 psi oil at US$20 per barrel. These costs were largely(82 kPa)roughly doubled evaporative emissions."8 offset by credits for improved fuel economy and
The effect is even greater in evaporation-con- reduced fuel loss through evaporation, leaving atrolled vehicles. When fuel RVP was increased lower net cost to the consumer of approximatelyfrom 9 psi (62 kPa) to 12 psi (81 kPa) RVP fuel, US$0.0012 per liter.USEPA found average diurnal emissions (evapo-rative emissions from a vehicle due to heating Oxygenates. Blending small percentages of oxy-and cooling during the day) in vehicles with genated compounds such as ethanol, methanol,evaporative controls to increase more than 5 tertiary butyl alcohol, and MTBE with gasolinetimes. Also, the average hot-soak emissions enables more complete combustion. Oxygenates(evaporative emissions from a vehicle after it has reduce the fuel's volumetric energy content, whilebeen driven and parked; in the United States, hot- improving antiknock performance. Oxygenatessoak emissions are measured for one hour) in- thus make possible a potential reduction in leadcreased by 25-100 percent. " The large increase and harmful aromatic compounds. Assuming noin diurnal emissions from controlled vehicles is change in the settings of the fuel metering sys-due to saturation of the charcoal canister, which tem, adding oxygenates will reduce exhaust COallows subsequent vapors to escape into the air. and HC emissions. These reductions are becom-
Vehicle refueling emissions are also strongly ing less and less important due to recent modelsaffected by fuel volatility. In a comparative test that do not overfuel the engine, and better adap-on the same vehicle, fuel with 11.5 psi (79 kPa) tive learning fuel management systems.RVP produced 30 percent greater refueling emis-sionsthan gasoline with 10 psi (64 kPa) RVP (1.45 Other fuel variables: Sulfur. Lowering sulfurversus 1.89 grams per liter dispensed).2 0 In re- in gasoline lowers CO, HC, and NOX emissionssponse to data such as these, USEPA established from catalytic converter-equipped cars. As notednationwide summertime RVP limits for gasoline. by the Auto/Oil study, "The regression analysis
An important advantage of gasoline volatility showed that the sulfur effect (lowered emissions)controls is that they can affect emissions from was significant for HC on all ten cars, CO onvehicles already in use, and from the gasoline five cars, and NO- on eight cars. There were nodistribution system. Unlike new-vehicle emis- instances of a statistically significant increase insions standards, it is not necessary to wait for the emissions."21 To the extent that oxygenates aremotor vehicle fleet to turn over before they take sulfur-free, their addition would tend to lowereffect. The emissions benefits and cost-effective- gasoline sulfur levels. The study indicated thatness of lower volatility are greatest where a few NOX would go down by about 3 percent per 100of the vehicles in use are equipped with evapora- ppm sulfur reduction. Recently, the Canadiantive controls. Even when evaporative controls are Government has determined that sulfur causes at-commonly used, as in the United States, control- mospheric formation of fine particles and thatling volatility may still be beneficial to prevent sulfur reduction would yield 90 percent of thein-use volatility levels from exceeding those for health benefits expected from its proposed re-which controls were designed. formulations.
In 1987, USEPA estimated that the long-termrefining costs of meeting a 9 psi (62 kPa) RVP Other fuel variables. Results of the Auto/Oillimit throughout the United States would be ap- study demonstrated that "NOX emissions were
CLEAN FuELs FoR AsI: TECHNICAL OPuONs FOR MOVING TowARDs UNLEADED GAsoarE AND LOW-SuLFUR DIESEL 20
lowered by reducingolefins, raised when T9. Box 2.5: Impact of Oxygenate Usedwas reduced; and onlymarginally increased MTBE: Canbeaddedto gasolineup to 2.7percentwithoutany significantincreasewhen aromatics were in NO . Two opposing effects appear to take place with addition of oxygenates.lowered."22 In general, 1. Enleanment, which tends to raise NOX.reducing aromatics and 2. Lower flame temperatures, which tend to reduce NOX.T caused statistically With MTBE levels below the equivalent of 2.7 percent oxygen, the lower
90 y flame temperature effect seems to prevail.significant reductionsin exhaust mass Ethanol: Can be added to gasoline at levels as high as 2.1 percent oxygen with-NMHC and CO emis- out significantly increasing NO. levels; above that point levels could increasesions. Reducing olefins (e.g., USEPA test data on over 100 cars indicates that oxygen levels of 2.7 per-increases exhaust mass cent or more could increase NO, emissions by 3-4 percent). The Auto Oil AirNMHC emiss ions . Quality Improvement Research Program (Auto/Oil) concluded that there was a
N co emissions. statistically significant increase (of about 5 percent) in NO with the addition ofHowever, "the ozone 10 percent ethanol (3.5 percent oxygen).forming potential" ofthe total vehicle emis- ETBE: Appears to be an attractive source of oxygenates. However, not. enoughsions was reduced.2 3 data exists regarding its NOx impact to come to a reasonable conclusion about it.
Regarding toxins, The Auto/Oil study revealed an approximately 6 percent increase in NO,, but thethe reduction of aro- I results were not statistically significant.
matics from 45 percentto 20 percent causedthe following: determining cost effectiveness. USEPA studied1. 42 percent reduction in benzene but a 23 per- these two integral parts: results derived from re-
cent increase in formaldehyde, finery modeling performed by Turner, Mason, and2. 20 percent increase in acetaldehyde and about Company (for theAuto-Oi/Economics group) and
a 10 percent increase in 1,3-Butadiene, and Bonner & Moore Management Science (for3. 31 percent reduction in 1,3-Butadiene, but in- USEPA). Survey results presented by the Cali-
significant impacts on other toxins. fornia Air Resources Board (CARB) were also fig-Reducing olefins from 20 percent to 5 percent ured into the study.
resulted in a 31 percent reduction in 1,3-Butadi- The total manufacturing cost of producingene but had an insignificant impact on other reformulated gasoline is the sum of the capitaltoxics. Lowering the T90 from 360°F to 280°F recovery cost and the operating cost. An exampleresulted in statistically significant reductions in of the individual fuel component costs and thebenzene, 1 ,3-Butadiene (37 percent), formalde- associated incremental percent reduction in VOChyde (27 percent), and acetaldehyde (23 percent). emissions (as compared to U.S. industry average
for 1990) is shown in table 2.4.Cost-effectiveness. Itisdifficulttoestimatethecosts USEPA proposed a range of VOC standardsand cost-effectivenessoffuelmodification, because and NOx standards based on particular combina-fuels'characteristicsdifferwidelyfromonerefiner tions of fuel component controls which reduceto another. Individual fuel component control VOC (and VOC plus NO) emissions at a cost ofcosts, and the effects of changes in one fuel com- less than US$5,000 and less than US$10,000 perponent versus another are two integral parts in ton, respectively. USEPA believes these ranges
21 CHAPIER 2: GAsoLiNE
to represent the upperlimit of costs that will Table 2.4: Component Control Costs and VOC Emissionsbe incurred by many Reductionsozone non-attainmentareas while achieving Component Control Level Incremental Cost Cumulative VOCattainment. (c/gallon) Reduction (%)
Estimates of the Oxygen 2.0 Wt% 1.67-3.36* 9.0costs and cost effec-tiveness of California Benzene 1.0 vol % 0.69 9.0RFG continue to come RVP 8.1 psi 0.57 17.6down. While develop- RVP 7.4 psi 1.67 25.3ing regulations, CARBestimated costs to be Sulfur 160 ppm 0.35-0.57 26.4US$0. 12-0.17 per gal- Oxygen 2.7 Wt % 0.59-1.18 *
lon. Recently, a Olefins 5.0 vol % 1.81-2.44 30.2USEPA analysisplaced the costs at Sulfur 50 ppm 1.45-1.86 31.2US$0.08-0.11 per gal- Aromafics 20% 0.61-0.98 31.4lon (US$0.02-0.03 per Based on MTBE.liter). This analysis es-timated the cost effec- Source: Based on discussions with USEPA.tiveness of the Califor- _ _______nia RFG to beUS$4,100-5,100 perton of VOC and NO control; Federal Phase 1 ers for the two-stroke vehicles, would deter adul-RFG was estimated to cost US$3,100 per ton of teration of gasoline and lubricating oils.VOC control.24
CONCLUSIONS REGARDING CLEANERLUBRICANTS FOR Two-STRoKE ENGINES GASOLINE
Thereis avisible"blue"orwhitesmokeinthe ex- 1. A growing body of data on lead's adversehaust of a two-stroke engine, due to the all-loss health effects, especially in young children,system of lubrication. This is further exacerbated indicates there may be no "safe" level. Re-by excessive use of lubrication, especially if the duced lead in gasoline has been shown to re-lubricant or gasoline is adulterated, or used in a duce the risk of behavioral problems, loweredpoorly-maintained engine. The use of modem IQs, and decreased ability to concentrate.synthetic smokeless lubricants is recommended Adult health is also affected by blood leadfor two-stroke, engines (especially three-wheel- which increases the risk of high blood pres-ers) in urban areas. The environmental benefits sure and cardiovascular diseases.far outweight the small extra cost. A government 2. Lead scavengers that accompany leaded gaso-requirement mandating the dispensing of quality line have been identified as human carcino-lubricants, along with gasoline at authorized deal- gens; eliminating lead in gasoline will reduce
CLEAN FUELS FOR ASIA: TECHxrCAL OPnoNs FOR MOVTIG TowARDs UNLEADED GASOUNE ND L OW-SULFUR DIESEL 22
this cancer risk. purchase of cheaper leaded fuel, increasing the3. Studies in both Europe and the United States risk of damaging the catalytic converter.
show that gasoline lead is responsible for about 9. Reformulating gasoline by modifying param-90 percent of airborne lead and that 1 micro- eters such as volatility, oxygenates, sulfur lev-gram per cubic meter of ambient lead will cause els, and HC mix can reduce HC, CO, and toxica 1-2 microgram per deciliter increase in blood emissions significantly.lead levels. This is in addition to the lead bur- 10. Using oxygenates such as MTBE in cold tem-den which may be associated with food, drink- perature environments clearly reduces CO, buting water, and other sources; this burden can has raised concerns regarding adverse healthvary dramatically from country to country. effects in certain susceptible individuals. Stud-
4. The availability of lead-free gasoline can fa- ies to date by USEPA and several U.S. statescilitate extensive reductions in other major have failed to identify a serious problem, butmotor vehicle pollutants, hydrocarbons, CO, additional studies are ongoing.NOX, aldehydes, and polynuclear aromatic hy-drocarbons (PAHs), by allowing the use ofcatalytic converters. ENDNOTES
5. Motor vehicle emissions of HC, CO, and NOxcause or contribute to a wide range of adverse 1. Royal Commission on Environmental Pollu-impacts on public health and general well-be- tion. April 1983. "Lead In The Environment,"ing. Those impacts include increased angina Ninth Report.attacks in individuals suffering from angina 2. Schwartz, Joel. April 6, 1983. "Health Effectspectoris, greatersusceptibilitytorespiratoryin- of Gasoline Lead Emissions," U.S. Environ-fection, more respiratory problems in school mental Protection Agency, Washington, DC.children, increased airway resistance in asth- 3. Annest, J. Lee. 1983. "Trends In Blood Leadmatics, eye irritation, impaired crop growth, Levels of the United States Populations," Leaddead lakes, and forest destruction. Emissions Versus Health.reductions can occur simultaneously with re- 4. U.S. Court of Appeals, No. 82-2282, Smallductions in fuel consumption and vehicle main- Refiner Lead Phase-Down Task Force, et. al.tenance. Studies in Canada support reduced v. USEPA, April 22, 1983.maintenance costs, as a result of using un- 5. Facchetti May 10-11,1983. "The Isotopic Leadleaded gasoline, of about Can$0.024 per liter. Experiment,"; "Isotopic Lead Experiment, Sta-
6. The best strategy for eliminating lead in gaso- tus Report," Facchetti and Geiss, Commissionline is to eliminate its use over a specific time of the European Communities, 1982.period, as several countries have done. 6. Facchetti. May 10-11, 1983. "The Isotopic
7. Tax policies that price unleaded fuel substan- Lead Experiment."tially lower than leaded fuel have been found 7. For a compelling analysis of the health im-to be very effective in stimulating the sales of pacts of leaded gasoline, see Lovei, Magda.unleaded fuel. Hong Kong and Singapore have August 1996. "Phasing Out Lead from Gaso-adopted such policies. line: World-Wide Experiences and Policy Im-
8. Countries concerned about limited supplies of plications," Environment Department Paperunleaded gasoline may wish to maintain a No. 40, The World Bank, Washington, DC.higher price for unleaded gasoline. This strat- 8. Gray and Azhari. "Saving Maintenance Dol-egy, however, tends to favor the continued lars With Lead-Free Fuel," SAE # 720014.
23 CHAP7ER 2: GASOuiNE
9. Hinton et al. "Gasoline Lead Additive And Emissions from Modem European VehiclesCost Effects of Potential 1975-1976 Emission and their Control," SAE Paper No. 880315,Control Systems," SAE # 730014. SAE International: Warrendale, Pennsylvania.
10. Hinton et al. "A Study of Lengthened Engine 19. Office of Mobile Sources. 1987. DraftRegula-Oil-Change Intervals," Pless, SAE # 740139. tory Impact Analysis: Control of Gasoline
11. Mowle, M.G. 1981. "The Benefits of Un- Volatility andEvaporative Hydrocarbon Emis-leaded Petrol," Institution of Engineers Trans- sions From New Motor Vehicles. U.S. Envi-portation Conference. ronmental Protection Agency: Washington, DC.
12. Mowle, M.G. 1981, op. cit. 20. Braddock, J.N. 1988. "Factors Influencing13. Michael, R. Bruce, USEPA. October 8-11, the Composition and Quantity of Passenger
1984. "Misfueling Emissions of Three-Way Car Refueling Emissions: Part II," SAE Pa-Catalyst Vehicles," presented at the Society per No. 880712, SAE International:of Automotive Engineers, Fuels and Lubri- Warrendale, Pennsylvania.cants Meeting, SAE Paper #841354. 21. Auto/Oil Air Quality Improvement Research
14. (Emissions)/(Emissions with no lead). Program. February 1991. "Effects Of Fuel15. Weaver, C.S. 1986. "The Effects of Low- Sulfur Levels On Mass Exhaust Emissions,"
Lead and Unleaded Fuels on Gasoline En- Technical Bulletin No. 2.gines," SAE Paper No. 860090, SAE Interna- 22. Auto/Oil Air Quality Improvement Researchtional: Warrendale, Pennsylvania. Program. December 1990. "Initial Mass Ex-
16. The Canadian government has recently an- haust Emissions Results From Reformulatednounced its intention to ban the use of MMT in Gasolines," Technical Bulletin No. 1.unleaded gasoline because of concerns regard- 23. Colucci and Wise. June 7,1992. "Auto/Oil Airing its potential impact on catalyst performance Quality Improvement Research Program-and oxygen sensors and onboard diagnostics. What Is It and What Has It Learned?" presented
17. Ha, Kong. 1994. Information on Hong Kong's at XXIV Fisita Congress, London, England.Unleaded Gasoline Program. Environmental 24. Atkinson, Dr. R. Dwight. May 1993. "TheProtection Agency, Hong Kong, China. Case For California Reformulated Gasoline-
18. McArragher, J.S. et al. 1988. "Evaporative Adoption By the Northeast."
CHAPTER 3:DIESEL FUEL
The quality and composition of diesel fuel can review of controls on diesel-fueled vehicles, seehave important impacts on pollutant emissions. appendix C.)Diesel-powered vehicles are an important partof commercial vehicle fleets throughout theworld. They also produce large amounts of SULFUR
particulate matter emissions from unburned fueland lubricating oil, and from sulfur in the fuel. Diesel emissions contain sulfur in particulate andDiesel particulate emissions are very small and gaseous form, and thus any reduction in sulfurthus have a maximum health impact. Because has dual advantages. Recent evaluations carrieddiesel combustion produces very high flame out in Europe show the benefits of reduced sul-temperatures, high amounts of nitrogen oxides fur in diesel fuel for lowering particulates. For(NO) are produced. NOX contributes to example, preliminary data released from the Autolphotochemical smog and, through secondary Oil study showed that lowering the diesel fuelatmospheric transformations, to particulate sulfur level from 2000 particles per million (ppm)aerosols. Improved engine designs and, very to 500 ppm reduced overall particulate from light-recently, add-on devices such as oxidation duty diesels by 2.4 percent, and from heavy-dutycatalysts or particulate filters have achieved diesels by 13 percent.' The relationship betweenconsiderable success in reducing particulate particulates and sulfur level was found to be lin-matter emissions. Traps that rely on fuel additive ear; for every 100 ppm reduction in sulfur, therecatalysts such as cerium for semi-continuous is a 0.16 percent reduction in particulate fromregeneration have also been successful in light-duty vehicles and a 0.87 percent reductionreducing emissions. However, even with these from heavy-duty vehicles.advances, cleaner diesel vehicle particulate USEPA has also established a clear relation-emissions remain much higher than from ship between sulfur in diesel fuel and particulatecomparable gasoline-fueled vehicles. (For a emissions.2 The direct sulfate emissions factor
(grams per mile) is calculated as follows:DSULV = 13.6 * (1.0 + WATER) * FDNSTY *
SWGHTD * DCNVRT/FEBox 3.1: Fuel Variables Found to Have a DSULV: direct sulfate emissions factor for a classSignificant Inpact on Pollutant Emissions and model year of vehicles.
DCNVRT: fraction of sulfur in the fuel that is1. Sulfur content and the fraction of aromatic hy- converted directly to sulfate (2.0 percent).
drocarbons contained in the fuel. FDNSTY: density of diesel fuel (7.11 pounds per2. Volatility of the diesel fuel (85 or 90 percent dis- gallon).
tilled temperatures).3. Use of fuel additives. FE: fuel economy for the class and model year
of the vehicles.
25
CL FuVIs FOR Asu: TsCJIMCAL OPI7ovS FOR MOvING TowARDs UNLEADED GASOUNE AND Low-SULFUR DIESEL 26
SWGHTD: weight percent of sulfur in diesel fuel. content and composition. These were further re-WATER: weight ratio of seven water molecules vised in January 1992 to the classifications sum-
to sulfate, 7 * 18/96 = 1.3 1. marizedintable3.1. Figure 3.1 illustrates theben-13.6: units conversion factor = (453.59 * 3)/100 efits produced by using very low-sulfur diesel fuel
where 453.59 = number of grams in a pound, on urban buses in Finland.3
3 = weight ratio of SO4 to sulfur, and the divi- Certain precious metal catalysts can oxidizesion by 100 is to correct for the weight per- SO2 to sulfurtrioxide (SO3), which combines withcent of sulfur. water in the exhaustto form sulfuric acid. The rateThe gaseous sulfur emissions factor is calcu- of conversion with the catalyst depends on the
lated as follows: temperature, presence of contaminants (e.g., sul-SO 2 EF.=9.07 * FDNSTY * SWGHTD * (1- fur), and oxygen content of the exhaust and on
CNVRT)/FE the activity of the catalyst. Generally, catalyst for-SO2EF = the sulfur emissions factor of a vehicle mulations that are most effective in oxidizing hy-
of a given class and model year. drocarbons and CO are also most effective at oxi-9.07: units conversion factor = (453.59 * 2)/100 dizing S02. The presence of sulfur in diesel fuel
where453.59 =numberofgrams in apound 2= thus limits the overall usefulness of emissionsweightratio of SO2 tosulfur, and the divi-sionby IOGisto con- Table 3.1: Environmental Classiftcations for Swedenvert for the weight Fuel Characteristic Urban Diesel 1 Urban Diesel 2 Standardpercentof sulfur.Clearly, improving Maximum Sulfur (%) 0.001 0.005 0.2
diesel fuel quality re- Maximum Aromatics (%) 5 20duces diesel emissions Maximum PAH (%) 0.02 0.1and increases the pros-pectsforadvancedafter- Distiliation:treatment technology. IBP (min) 0 C 180 180Sweden and Finland 10 percent (min) - - 180have shown that very 285 295low-sulfur diesel fuel is 95 percent (max)feasible and beneficial. Density (kg/m3) 800-820 800-820Both countries have in- Cetane Number 50 47 ##troduced the use ofvery Tax Rate ($/m3)@ 126 165 199low-sulfur fuel (lessthan 0.005 percent by Notes:weight), resulting in In addition to the urban grades, one summer and three winter standard grades are specified.
substantially reduced *95 percent distllaton varies with grade: Summer 370; Winter 340
sulfur emissions. # Density varies with grade: Summer 820-860 kg/m3; Winter 800-845 (-26 C); Winter 800-840Sweden introduced (-32 and -38 C grades)
environmental classifi- #W 45-49
cations for diesel fuel inJationuafory diese 199 with t @ 1994 tax rates exclude added value tax.January 1991, wb th taxrelief for both sulfur Source: The Swedish Environmental Protection Agency (1996).
27 CHAPIER 3: DIESeL FuEL
Figure 3.1: Emissions from Buses in Finland
NOx (G/kWh) Particulate (G/kWh)
16 0.414 NOx12 Particulate
100D
8 0.264 0.12
0 0~~~
Note: OB = Old Bus; MB = Modem Bus; NF = Normal Fuel; CF = City Diesel; CAT = Oxidation CatalystsSource: Mikkonen, Seppo, and Neste Oy. June 5, 1993. "Reformulated Fuels Reduce Automotive Emissions,"
Finnish Air Pollution Prevention Vews.
catalysts or catalytic trap-oxidizers for reducing horsepower per hour, this is equivalent to 0.85environmental impact. grams per horsepower-hour. For comparison, the
Atmospheric SO2 oxidizes to formn sulfate par- average rate of primary or directly emitted par-ticles much the way it does in the precious metal ticulate emissions from heavy-duty diesel enginescatalyst. Thepresence ofthe catalystmerely speeds in use was about 0.8 grams per horsepower-hour.up areactionwhichwould occur anyway (although Aside from its particulate-forming tendencies,this can have a significant effect on human expo- SO2 is recognized as a hazardous pollutant in itssure to reaction prod-ucts). According toanalysis by CaliforniaAir Resources Board Box 3.2: Options to Reduce the Sulfur Content of Diesel Fuelstaff roughly 1.2 poundsof secondary particulate * In the crude state, increase the proportion of low-sulfur crude oil.is formed per pound of * Reduce the cut point of diesel fractions from both primary distillation as wellSO2 emitted inthe South as from the fractionation of secondary processing streams to 350-3600C.
Coast Air Basin. For a Improve fractionation efficiency to eliminate inter-stream overlaps during frac-tionation of diesel oils.
diesel engine burning * Hydro-treat straight-run diesel and thermally cracked diesel and/or hydrofine;fuel of 0.29 percent by reduce proportions of FCC oil blended into final product diesel oil.weight of sulfur at 0.42 * Install hydrocrackers that would enable production of very low-sulfur satu-pounds of fuel per rated diesel with high cetane numbers.
CL&N FUEIs FOR Asw: TEcHNcAL OPr7oNS FOR MoVING TOwARDs UN&EADED GASOLNE AND LOW-S ULFUR DIESEL 28
own right. The health and welfare effects of SO2 AROMATIC HYDROCARBON CONTENTin diesel vehicle emissions are probably muchgreater than that of an equal quantity emitted from Aromatic hydrocarbons are com poundsa utility stack or industrial boiler, since motor ve- containing one or more benzene-like ringhicle exhaust is emitted close to ground level near structures. They are distinguished from paraffinsroads, buildings, and people. and naphthenes, the other major hydrocarbon
A study documenting health and non-health constituents of diesel fuel, which lack suchair pollution darnages from various fuels in Asia structures. Aromatic hydrocarbons are denser,found diesel to have the highest social costs per have poorer self-ignition qualities, and produceton of fuel. Impact varied across cities and coun- more soot in burning. Ordinarily, "straight run"tries; however, the analysis suggest that aggres- diesel fuel produced by simple distillation ofsive policies are needed to encourage the use of crude oil is fairly low in aromatic hydrocarbons.cleaner fuels (especially low-sulfur diesel).4 However, catalytic cracking of residual oil to
increase gasoline and diesel production resultsin increased aromatics content. A typical straight
VOLATILITY run diesel might contain 20-25 percent aromaticsby volume, while a diesel blended from
Diesel fuel consists of a mixture of hydrocarbons catalytically cracked stocks could have 40-50having different molecular weights and boiling percent aromatics.points.5 As a result, some of it boils away on heat- Aromatic hydrocarbons have poor self-igni-ing, while the remainder's boiling point increases. tion qualities, so diesel fuels containing a highThis fact is used to characterize the range of hy- fraction of aromatics tend to have low cetanedrocarbons in the fuel in the form of a "distilla- numbers. Typical cetane values for straight runtion curve," specifying the temperature at which diesels are in the range of 50-5 5; those for highlyvarious percentages of the hydrocarbons have aromatic diesel fuels are typically 40-45, and mayboiled away. A low T1o is associated with a sig- be even lower. This produces delays in startingnificant content of relatively volatile hydrocar- vehicles when the engine is cold, and increasesbons. Fuels with this characteristic tend to ex- combustion noise, HC, and NOX.hibit somewhat higher HC emissions than others. Increased aromatics content is also correlatedA relatively high T90 is considered to be associ- with higher particulate emissions. Aromatic hy-ated with higher particulate emissions. drocarbons have a greater tendency to form soot
In a Dutch study, the test fuels were composed while burning, and the poorer combustion qual-of two clearly different sets-T8 5 and T90, be- ity also appears to increase particulate solubletween which sulfur content varied independently. organic fraction (SOF) emissions. Increased aro-A highly significant effect of T85 90 was found, matic content may also be correlated with in-in addition to a significant sulfur effect and a creased SOF mutagenicity, possibly due to in-probably significant aromatics content effect. A creased polycyclic nuclear aromatics (PNA) andtypical effect ofa2 0°C change in T85is 0.05 grams nitro-PNA emissions. There is also some evi-per kWh at present particulate levels. As men- dence that more highly aromatic fuels have ationed earlier, this may be related to generally greater tendency to form deposits on fuel injec-higher T85 or T90, which in the test fuels went up tors and other critical components. Such depos-to 350-360°C. Commercial diesel fuels in Eu- its can interfere with proper fuel/air mixing,rope show values up to about 370°C. greatly increasing PM and HC emissions.
29 CHJAPTER 3: DIEsEL FUEL
OTHER FUEL PRO]PERTIES inhibit soot formation during the combustion pro-cess, and thus greatly reduce visible smoke emis-
Other fuel properties may also have an effect on sions. Their effects on the particulate SOF areemissions. Fuel density, for instance, may affect not fully documented, but one study of a bariumthe mass of fuel injected into the combustion additive has shown a significant increase in thechamber, and thus the air/fuel ratio. This is be- polynuclear aromatic hydrocarbons (PAH) con-cause fuel injection pumps meter fuel by volume, tent and SOF mutagenicity.not by mass, and a denser fuel contains a greater Particulate sulfate emissions are greatly in-mass in the same volume. Fuel viscosity can also creased with these additives, since they readilyaffect the fuel injection characteristics, and thus form stable solid metal sulfates which are emit-the mixing rate. The fuel's corrosiveness, clean- ted in the exhaust. Thus, the overall effect of re-liness, and lubricating properties can all affect ducing soot and increasing metal sulfate emis-the fuel injection equipment-possibly contrib- sions may be either an increase or decrease inuting to excessive in-use emissions if the equip- the total particulate mass, depending on the sootment wears out prematurely. Reducing fuel den- emissions level at the beginning, and the amountsity is an effective means of reducing fine of additive used.particulate emissions.
Detergent additives (often combined with a cet-ane enhancer) help to prevent and remove coke
FUEL ADDITIVES deposits on fuel injector tips and other vulnerablelocations. By maintaining new engine injection
Several generic types of diesel fuel additives, and mixing characteristics, these deposits can helpincluding cetane enhancers, smoke suppressants, to decrease in-use PM and HC emissions. A studyand detergent additives, can also have a signifi- for the California Air Resources Board (CARB)cant impact on emissions. In recent years some estimated that fuel injector problems of trucks inadditive research has been directed specifically use cause PM emissions that are 50 percent higherat emissions reduction. than those from new vehicles. A significant frac-
Cetane enhancers are used to improve diesel tion of this PM emissions excess is unquestion-fuel's self-ignition qualities. These compounds ably due to fuel injector deposits.are generally added to reduce combustion noiseand ignition delays, both adverse impacts of higharomatic fuels. Cetane enhancers also appear to CoNcLusIoNs REGARDING CLEAN DIESEL FUELreduce the aromatic hydrocarbons' adverse im-pacts on HC and PM emissions. However, PM 1. There is a clear worldwide trend toward loweremissions are somewhat higher than what would levels of sulfur in diesel fuel. At a minimum,result from the use of a higher quality fuel. These this would reduce particulate emissions fromfindings are not universal. A Dutch study detected diesel vehicles, and in turn, health impacts.no significant effect of ashless cetane-enhancers Recent European studies indicate that for ev-on NOX or particulates. ery 100 ppm sulfur reduction, there is a 0.16
percent reduction in particulates from light-Smoke-suppressing additives are organic com- duty vehicles, and a 0.87 percent reductionpounds of calcium, barium, or sometimes mag- from heavy-duty vehicles.nesium. Added to diesel fuel, these compounds 2. Other diesel fuel properties such as volatility,
CBANv Fus FoR ASI: TECHPMCAL OP7ONs FoR MOnNG TowARDs UNmADED GASOLINE AD Low-SULFUR DIESEL 30
density, aromaticcontent,andadditives canhave 2. U.S. Environmental Protection Agency. Feb-positive or negative effects on diesel vehicle ruary 1995. "Draft Users Guide To Part 5: Aemissions. Increasingthecetane numberofthe Program For Calculating Particle Emissionsfuel usually has beneficial effects on emissions. From Motor Vehicles."
3. In addition to the adoption of mandatory lim- 3. Mikkonen, Seppo and Neste Oy. June 5, 1993.its, studies show that tax policies can be very "Reformulated Fuels Reduce Automotiveeffective in encouraging the introduction and Emissions," Finnish Air Pollution Preventionuse of low-polluting diesel fuels. News.
4. Maddison et al. 1997. "Air Pollution and So-cial Costs of Fuels," The World Bank (forth-
ENDNOTES coming).5. TI is the temperature at which 10 percent of
1. The Auto/Oil Programme, informal briefing, the fuel evaporates; T90 is the temperature atBrussels, March 21, 1995. which 90 percent of the fuel evaporates.
CHAPTER 4:ALTERNATIVE FUELS
The possibility of substituting cleaner-burning al- Alternative fuels include the following:ternatives for gasoline has drawn increasing at- * methanol (derived from natural gas, coal, ortention over the last decade. Motives for these biomass);substitutions include conservation of oil products * ethanol (derived from grain);and energy security, as well as reducing or elimi- * biodiesel (derivedfrom vegetableorotheroils);nating pollutant emissions. Some alternative fu- * compressed natural gas (CNG, mainly com-els offer large, cost-effective reductions in pol- posed of methane),lutant emissions. Alternative fuels' air quality * liquefied petroleum gas (LPG, composed ofclaims must be evaluated carefully, because in propane and butane);many cases similar or even greater emissions re- * electricity;ductions can be obtained with a conventional fuel * hydrogen; andby using a more advanced emissions control sys- * synthetic liquid fuels derived from hydroge-tem. Which approach is more cost-effective de- nation of coal, and various fuel blends such aspends on the relative costs of the conventional gasohol.and the alternative fuel.'
Table 4.1: Properties of Conventional and Alternative Fuels
Fuel Type Diesel Gasoline Methanol Ethanol Propane Methane
Energy content (LHV) (MJAkg) 42.5 44.0 20.0 26.9 46.4 50.0
Liquid density (kg/1) 0.84-0.88 0.72-0.78 .792 .785 .51 .4225
Liquid energy density (MJA) 36.55 33.0 15.84 21.12 23.66 21.13
Gas energy density (MJ/I)
- @ atmospheric -- 0.093 0.036
-@ 200 bar - - 7.47Boiling point, OC 140-360 37-205 65 79 -42.15 -161.6
Research octane no. -25 92-98 106 107 112 120
Motor octane no. -- 80-90 92 89 97 120
Cetane no. 45-55 0-5 5 5 -2 0
Source: Derived from analysis prepapred by Chris Weaver. A. Faiz, and Michael Walsh, November 1996. "Air Pollution fromMotor Vehicles: Standards and Technologies for Controlling Emissions.'
31
CLE,N FuELs FOR ASIA: TEmcN OP27ONS FOR MOVING TowARDs UNIEADRD GAsoUNE AND LOW-SULFuR DiESEL 32
NATURAL GAS Natural gas engines can be grouped into threemain types by combustion system-stoichiomet-
Natural gas (85-99 percent methane) has many ric, lean-bum, and dual-fuel diesel.desirable qualities as a spark-ignition engine fuel. Most NGVs now in operation have stoichio-Clean-burning, cheap, and abundant in many metric engines that have been converted fromparts of the world, natural gas already plays a gasoline engines. These engines are either bi-fuelsignificant role in Argentina, Canada, Italy, New (able to operate on natural gas or gasoline) orZealand, Russia, and the United States. Recent dedicated to natural gas. In the latter case, theadvances in natural gas vehicle and engine tech- engine can be optimized for natural gas by in-nology in a number of countries have combined creasing the compression ratio and making otherto boost natural gas' visibility and market poten- changes, although this is not usually done in ret-tial as a vehicle fuel. Other advances include new rofitting situations because of the cost. Nearlystorage cylinder technologies, international stan- all present light-duty NGVs use stoichiometricdardization, and new factory-manufactured natu- engines with or without three-way emissions cata-ral gas vehicles (NGVs). These have helped en- lysts. A few heavy-duty natural gas vehicles alsohance the market potential of natural gas. use stoichiometric engines.
Nearly all NGVs now in operation have beenretrofitted from gasoline models. Natural gas' Lean-burn engines use an air-fuel mixture withphysical properties make these conversions rela- significantly more air than is required to burn alltively easy. A typical conversion costs about of the fuel. The extra air dilutes the mixture andUS$1,500-4,000 per vehicle, due mostly to the reduces the flame temperature, reducing engine-on-board fuel storage system's cost. Current fuel out nitrogen oxide (NO) emissions and exhaustprices mean that many high-use vehicles could temperatures. Reduced heat losses and variousrecover this cost in a few years due to fuel cost thermodynamic advantages make lean-bum en-savings. gines approximately 10-20 percent more efficient
In recent years, several thousand new, factory- than stoichiometric engines. Without turbocha-built light-duty NGVs have been produced in the rging, however, a lean-burn engine's power out-United States, mostly by the Chrysler Corpora- put is less than that of a stoichiometric engine.tion. Ford has announced plans to begin limited Turbocharging reverses the situation because leanproduction of an optimized natural gas passen- mixtures knock less readily. Therefore, lean-bumger car in 1996. The Chrysler and Ford vehicles engines can be designed for higher levels of turbo-incorporate fuel metering and emissions control charger boost than stoichiometric engines, thussystems similar to those in modern fuel-injected achieving higher power output. These engines'gasoline vehicles. These vehicles are the cleanest lower temperatures also contribute to engine lifenon-electric motor vehicles ever made-easily and reliability. For these reasons, most heavy-meeting California's stringent ultra-low vehicle duty natural gas engines have a lean-bum design.emissions standards. Their incremental cost in This category includes a rapidly-growing num-their present, limited-volume production, range ber of heavy-duty lean-bum engines developedabout US$4,000-5,500 more than gasoline ve- and marketed specifically for vehicular use.hicles, or about 20 percent of the selling price.Estimates claim that under mass production the Dual-fuel diesel engines are a special type of lean-incremental cost would drop to around bum engine in which the air-gas mixture in theUS$1,500-2,500 per vehicle. cylinder is ignitednotby asparkplugbutby injec-
33 CHAP=ER 4: ALJERmnAJTE FURTs
tion of a small amount of diesel fuel that self-ig- in emissions-critical applications, such as urbannites. Most diesel engines can readily be converted transit buses and delivery trucks. These enginesto dual-fuel operation, retaining the option to run incorporate low-NO, technology used in station-on 100 percent diesel fuel if natural gas is not ary natural gas engines, and typically an oxida-available. Because of the flexibility this allows, tion catalyst. They are capable of achieving verythe dual-fuel approach has been popular for low NOx, particulate, and other emissions levelsheavy-duty retrofit applications. Current dual- (less than 2.0 grams per BBP-hr NO, and 0.03fuel engine systems tend to have very high HC grams per BHP-hr particulate) with high effi-and CO emissions due to the production of mix- ciency, high power output, and most likely, longertures too lean to burn at light loads. However, life. Three such engines have recently been cer-developments such as timed gaseous fuel injec- tified in California: the Cummins L 10 engine fortion systems, promise to overcome this problem. transit buses, and the Hercules 5.61 and 3.71 en-
Sincenaturalgasismostlymethane,NGVshave gines for school buses and medium trucks.lower non-methane hydrocarbon (NM1C) emis- Natural gas costs vary greatly from countrysions than gasoline vehicles, but higher methane to country, and even within countries, due to in-emissions. When the fuel system is sealed, there frastructure and transport costs. Where gas isare no evaporative or running-loss emissions, and available by pipeline from the field, its price isrefueling emissions are negligible. Cold-start emis- normally set by competition with residual fuelsions from NGVs are also low since cold-start oil or coal. Market-clearing price under theseenrichment is not required, reducing both NMHC conditions is typically about US$3.00 per mil-and CO emissions. NGVs are normally calibrated lion BTU (equivalent to about $0.41 per gallonwith somewhat leaner fuel-air ratios than gaso- of diesel fuel). Natural gas compression costs canline vehicles, which also reduces CO emissions. add another US$0.50-2.00 per million BTU,Given equal energy efficiency, carbon dioxide depending on the facility's size and the natural(CO2) emissions from NGVs are lower than from gas supply pressure.gasoline vehicles, since natural gas has a lower Liquefied natural gas (LNG) costs vary con-carbon content per unit of energy. In addition, siderably, depending on specific contract termsthe high octane value of natural gas (120 or more) (there is no effective "spot" LNG market). Small-makes it possible to attain increased efficiency scale natural gas liquefaction costs about US$2.00by increasing the compression ratio. Optimized per million BTU, normally making ituneconomicheavy-duty NGV engines may approach diesel compared to CNG. Where low-cost remote gas isefficiency levels. NOx emissions from uncon- available, LNG production can be quite economic.trolled NGVs may be higher or lower than com- Typical 1987 costs for LNG delivered to Japanparable gasoline vehicles, depending on the en- were about US$3.20-3.50 per million BTU. Ter-gine technology, but they are typically somewhat minal receipt and transportation would probablylower. Light-duty NGVs equipped with modern add about US$0.50 to the wholesale cost.electronic fuel control systems and three-waycatalytic converters have achieved NO emissionsmore than 75 percent below the California ultra- LIQUEFIED PETROLEUM GAS
low vehicle emissions standards.In the last several years, a number of heavy- Liquefied petroleum gas (LPG) is already widely
duty engine manufacturers have developed die- used as a vehicle fuel in Canada, the Netherlands,sel-derived lean-burn natural gas engines for use and the United States. As a spark-ignition en-
CLEs.FunsFORASIA: TEcIHcA OPnONSsFORMOVING TowARDs UNLEADED GASOLINEAND LOw-SULFUR DIESEL 34
gine fuel, it has many of the same advantages as lean-combustion characteristics, low flame tem-natural gas, with the additional advantage of be- perature (leading to low NOX emissions), and lowing easier to transport. A major disadvantage is photochemical reactivity. Methanol's majorits limited supply, which would rule out any large- drawbacks are its cost and price volatility. Therescale conversion to LPG fuel. As with natural is little prospect for methanol to become price-gas, nearly all LPG vehicles presently in opera- competitive with conventional fuels unless worldtion are retrofitted gasoline vehicles. The costs oil prices increase greatly.of converting from gasoline to LPG are consid- With a fairly high octane number of 112 anderably less than those of converting to natural excellent lean-combustion properties, methanolgas, due primarily to the fuel tanks' lower cost. is a good fuel for lean-bum Otto-cycle engines.A light-duty vehicle typically costs about Its lean combustion limits are similar to those ofUS$800-1,500 to convert. As with natural gas, natural gas, while its low energy density resultsthe conversion cost for high-use vehicles usually in a flame temperature lower than hydrocarboncan be recovered within a few years through fuels, and thus lower NOX emissions.lower fuel costs. Engine technology for LPG Light-duty vehicles using M85 tend to havevehicles is very similar to that for NGVs, with NOx and CO emissions similar to gasoline ve-the exception that LPG is seldom used in dual- hicles. The total mass of tailpipe non-methanefuel diesel applications. organic gas (NMOG) emissions tends to be simi-
LPG has many of the same emissions charac- lar to (or higher than) gasoline vehicles, butteristics as natural gas. The two fuels are similar, NMOG's lower ozone reactivity results in simi-except that LPG is primarily propane (or a pro- lar or somewhat lower ozone impacts. Formal-pane/butane mixture), rather than methane, which dehyde emissions (a primary combustion prod-affects the composition of exhaust volatile or- uct of methanol) tend to be significantly higherganic compound (VOC) emissions. LPG is pro- than those from gasoline or other alternative fuelduced in the extraction of heavier liquids from vehicles. However, other toxic air emissions (es-natural gas, and as a by-product in petroleum re- pecially benzene) tend to be lower, while form-fining. Presently, LPG supply exceeds demand aldehyde emissions have been controlled success-in most petroleum-refining countries, which fully by emissions catalysts.keeps the price low relative to other hydrocar- Heavy-duty methanol engines are capable ofbons. Wholesale prices for consumer-grade pro- much lower NOX and particulate emissions thanpane in the United States have been about similar heavy-duty bus diesel engines, while en-US$0.25-0.30 per gallon for several years, or gine-out NMOG and formaldehyde emissionsabout 30 percent less than the wholesale cost of tend to be higher. However, these emissions havediesel on an energy basis. Depending on the lo- been controlled successfully by emissions cata-cation, however, the additional costs of storing lyst converters.and transporting LPG may offset this advantage. Methanol can be produced from natural gas,
coal, orbiomass. At current and foreseeable prices,the most economical methanol feedstock is natu-
METHANOL ral gas, especially where found in remote regionswhere natural gas has no ready market. The cur-
Widely promoted in the United States as a "clean rent world market considers methanol a commod-fuel," methanol has many desirable combustion ity chemical, rather than a fuel; world methanoland emissions characteristics, including good production capacity is limited and projected to
35 CHAPIER 4: ALmERAIA4Tv FuEIs
be tight through the 1990s and beyond. Metha- Emissions from ethanol-fueled engines are notnol is a feedstock in the production of MTBE, well characterized but are believed to be high inand anticipated increased demand for MTBE for unburned ethanol, acetaldehyde, and other alde-reformulated gasoline will place strong pressures hydes. Thesecanbe controlledwith emissionscata-on price and supply in the foreseeable future. lysts. Uncontrolled NOX emissions are somewhat
The world market price of methanol has fluc- higher than with methanol, but still lower thantuated dramatically in the last decade, from gasoline engines. Cold-starting ethanol engines isUS$0.25 per gallon in the early 1 980s to not a serious problem in the warm Brazilian cli-US$0.60-0.70 in the late 1980s. The lower price mate but would be a concern in colder countries.reflected a glut, while the higher value reflected a Ethanol is produced primarily by fermentingtemporary shortage. Recent estimates of the long- starch from grains or sugar (from sugar cane). Asterm supply price of methanol for the next de- a result, fuel ethanol production directly competescade are US$0.43-0.59 per gallon. This would be with food production in most countries. Ethanol'sequal to US$0.90-1.23 on an energy-equivalent resulting high price-US$1.00-1.60 per gallon inbasis (compared to present spot gasoline prices the United States in the last few years (equivalenton the order of US$0.70 per gallon). In addition to US$1.56-2.50 per gallon of gasoline on an en-to new methanol supply capacity, any large-scale ergy basis), has effectively ruled out its use as avehicular use of methanol would require substan- motor fuel except in Brazil and the United States,tial investments in fuel storage, transportation, where it is heavily subsidized. Brazil'sProoalcooland dispensing facilities, which would further program, promotingtheuse offuel ethanol in motorincrease the delivered cost of the fuel. vehicles, has attracted worldwide attention as the
most successful alternative fuel implementationprogram. Despite the availability of a large and
ETHANOL, inexpensive biomass resource, this program stilldepends on massive government subsidies.
Ethanol has attracted considerable attention as amotor fuel due to the success of the BrazilianProoalcool program. However, despite this BIODIESELprogram's technical success, the high cost of pro-ducing ethanol (compared to hydrocarbon fuels) Biodiesel is produced by reacting vegetable ormeans that heavy subsidies are required. animal fats with methanol or ethanol to produce a
Ethanol, the second lowest of the alcohols in lower-viscosity fuel similar in physical charac-molecular weight, resembles methanol in most teristics to diesel. Such fuels can be used as is orcombustion and physical properties. The major blended with diesel. Engines running on puredifference is ethanol's higher volumetric energy biodiesel tend to have lower black smoke and COcontent. Fuel-grade ethanol, as produced in Bra- emissions but higher NOX emissions, and possi-zil, contains several percent by weight of water. bly higher particulate emissions. These differencesIn addition, pure (anhydrous) ethanol is used as a are not very large. Other advantages of biodieselblend stock for gasoline both in Brazil and the include a high cetane number, very low sulfurUnited States. By blending 22 percent anhydrous content, and the fact that it is a renewable resource.ethanol with gasoline to produce gasohol, Brazil Disadvantages include high cost (US$1.50-3.50has been able to completely eliminate the need per gallon before taxes), reduced energy densityfor lead as an octane enhancer. resulting in lower engine power output, and a low
CIEAN FuEsFOR ASIA: TECHNCAL OPONSFORMOVING TowARDs UNAiD&D GASOLINE AND Low-S LFURDIESEL 36
flash point, which may be hazardous. Biodiesel's of convertingvegetableoils tobiodiesel is approxi-effects on engine performance and emissions over mately US$0.50 per gallon. Thus, the total biodiesellong-term use are not well documented. fuel cost is about US$2.50-3.50 per gallon. This
Although there are no published field test data is substantially higher than conventional diesel,on engine emissions or performance and dura- which currently costs about US$0.75 per gallonbility forvehicles using blended orneatbiodiesel, before taxes. If waste vegetable oil is used, thethere are some reports on short-term effects mea- cost of biodiesel may be reduced to roughlysured in the laboratory. The general consensus is US$1.50 per gallon. Since the heating value forthat blended or neat biodiesel has the potential to biodiesel is less than diesel, more fuel must bereduce CO emissions (although these are already burned to provide the same work output as die-low), smoke opacity, and measured HC emis- sel fuel, adding to biodiesel's cost disadvantage.sions. However, studies show an increase in NO.emissions from biodiesel fuel, compared to die-sel fuel under normal engine conditions. This is HYDROGEN
partly due to biodiesel's higher cetane number,which causes a shorter ignition delay and higher Hydrogenmaybe the cleanest-burning motor fuel,peak cylinder pressure (some may also be due to although many of its properties make it difficultthe fuel's nitrogen content). Reduction in smoke to use in motor vehicles. Hydrogen's potential toemissions is believed to be due to better com- reduce exhaust emissions stems from the absencebustion of the short-chain hydrocarbons found of carbon atoms in its molecular structure. Thein biodiesel, as well as the oxygen content's ef- only pollutant produced from hydrogen combus-fect. Other data also show that mixing oxygen- tion is NOX (lubricating oil may still contributeates with biodiesel indicates a reduction in HC small amounts of HC, CO, and particulates).emissions when biodiesel is used. However, the Hydrogen combustion also produces no directorganic acids and oxygenated compounds found CO2 emissions. Indirect CO2 emissions dependin biodiesel may affect the response of the flame on the nature of the energy source used to pro-ionization detector, thus understating the actual duce the hydrogen. In the long-term event of dras-HC emissions. The behavior of these compounds tic measures to reduce CO2 emissions (to helpwith respect to adsorption and desorption on the reduce the effects of global warming), hydrogensurfaces of the gas sampling system is not known. fuel produced from renewable energy sourcesMore studies are needed to understand the or- would be a possible solution.ganic constituents in the exhaust gases from Hydrogen can be stored on-board a vehicle asbiodiesel-powered engines before firm conclu- a compressed gas, liquid, or in chemical storagesions can be drawn regarding HC emissions. as metal hydrides. Hydrogen can also be manu-Controversy exists concerning the effect of factured on-board the vehicle by reforming natu-biodiesel on particulate matter emissions. ral gas, methanol, or other fuels, or by the reac-
Biodiesel's cost is the principal barrier, mak- tion of water with sponge iron.ing it less attractive as a diesel substitute. Vegetableoils used in making biodiesel cost aboutUS$2.00-3.00 per gallon. If the credit for glycerol THE ECONOMICS OF ALTERNATIVE FuELs(a by-product of the biodiesel transesterificationprocess, and a chemical feedstock for many in- Alternative transport fuel economics depend ondustrial processes) is taken into account, the cost the cost of production and the additional costs of
37 CHAPT7R 4: ALIERNAVE FuELs
storage, distribution, and end-use. Production costs taxis, and delivery trucks-with high annualare a function of abundance or scarcity of the mileage and restricted range) became competi-resources from which the fuel is produced, and tive. At US$20-30 per barrel, CNG fast-fill andthe technology required to extract those resources. propane-fueled low mileage vehicles would beThe additional costs of storage, distribution, and competitive. Methanol from natural gas becomesend vehicle use are also important. Gasoline, die- competitive above US$50 per barrel of crude oil,sel fuel made from heavy oils, and natural gas while synthetic gasoline and diesel fuel do notrequire relatively minor changes to existing dis- become competitive until the price of crude oiltribution and end-use systems, while CNG and reaches US$70 per barrel. For CNG-fueled ve-alcohol fuels require larger modifications. hicles, the high cost of fuel transport in tube trail-
Organization of Economic Cooperation and ers suggests that CNG would be competitive atDevelopment (OECD) estimates ofthe costs (pro- the crude oil prices indicated above only if fill-duction, distribution, and end-use) of alternative ing stations are located near a natural gas pipe-fuels are shown in table 4.2. These estimates are line or distribution network.based on 1987 costs and technology. AccordingtoOECD's International Energy Agency, CNG andVeryHeavy Oil (VHO)products couldbe economi- CLIMATE CHANGEcally competitive with conventional gasoline at1987 prices. Methanol and synthetic gasoline Climate change, or the "greenhouse effect," is amade from natural gas were close to competi- major stimulus for switching to alternative fuels.tive, under optimistic assumptions about gas This change in climate occurs when certain gasesprices. Methanol from coal or biomass, and etha- allow sunlight to penetrate to the earth but par-nol from biomass wereestimated to have a cost
at least twice that of Table 4.2: Comparative Costs of Alternative Fuels (1987)gasoline (IEA, 1990). ___________________________
AWorld Bank study Fuel Overall Cost (1987 US$ per barrel-gasoline energy(Moreno and Bailey, equivalent)1989) found that at Crude oil (assumed price) 18crude oil prices ofcrUde$1 l perires of Conventional Gasoline 27US$10 per barrel orlower (1988 prices), al- Compressed Natural Gas 20-46ternative fuels were Very Heavy Oil Products 21-34generallyuncompetitive. Methanol (from gas) 30-67At US$10-20 per bar- Methasol (f om gas) 3-61rel, custom-built pro- Synthetic Gasoline (from gas) 43-61pane-fueled high mile- Diesel (from gas) 69age vehicles and Methanol (from coal) 63-109retrofitted vehicles us- Methanol (fom biomass) 64-126ing CNG trickle-fill re-fueling (mostly appli- Ethanol (from biomass) 66-101cable to captive vehicle Source: Internatonal Energy Agency. 1990. "Substitute Fuels for Road Transport: Afleets-urban buses, Technology Assessment." OECD, Paris.
CLaAN FuEis FOR AsL4: TEcHmcA OPnoNs FOR MOVING TowARDs UNLEADED GASOUNE AND Low-SULFUR DIESEL 38
Table 4.3: Costs of Conventional and Alternative Fuels in the United States.
Gasoline (a) Methanol (b) Ethanol (c) LPG (c) CNG(d) LNG(e) Hydrogen
Wholesale 0.51-0.68 0.32-0.42 1.29-1.45 0.25-0.45 0.25-0.50 0.40-0.55 0.25($/galg)
Wholesale 0.41-0.54 0.56-0.74 1.70-1.91 0.29-0.53 0.26-0.52 0.53-0.72 0.85($/thermh)
Retail ($/gal) 0.97-1.32 0.80-0.92 n/a (i) 0.95-1.10 0.40-0.90 n/a 9.60-16.00
Retail 0.78-1.06 1.41-1.62 n/a 1.12-1.29 0.41-0.93 n/a 33.10-55.17($/therm)
(a) Gasoline wholesale and retail prices - Oil & Gas Journal, December 21, 1992, page 114.
(b) Methanol wholesale prices -Oxy-Fuel News, October 5, 1992, page 9.
Methanol retail prices - current California retail prices.
(c) Ethanol and LPG wholesale prices - Oxy-Fuel News, October 5, 1992, pp. 8-9. LPG retail prices - current California retail prices
(d) Wholesale and retail prices - Industry estimates
(e) LNG wholesale prices - Industry estimates
(f) Hydrogen retail prices are based on quotes from industrial gas suppliers.
(g) natural gas and hydrogen are priced in dollars per 100 ft3
(h) Therm -100,000 Btu
(i) n/a = not currently available at retail outlets
Source: Derived from analysis prepared by Chris Weaver, A. Faiz, and Michael Walsh, November 1996. *Air Pollution fromMotor Vehicles: Standards and Technologies For Controlling Emissions."
tially trap the planet's radiated infrared heat in sively warmer "heat trap." This phenomenon isthe atmosphere. Some of this warming is natural commonly referred to as "global warming."and necessary. Over the past century, however, Various human activities contribute to climatehuman activities have increased atmospheric con- change. Recent estimates indicate that by far thecentrations of naturally occurring water vapor, largest contributor (about 50 percent) is energyC02, methane, and other infrared-absorbing consumption, mostly from the burning of fossil(greenhouse) gases, and added new and very pow- fuels. The release of chlorofluorocarbons (CFCs),erful infrared-absorbing gases to the mixture. the second largest contributor to global warm-Even more disturbing, in recent decades the at- ing, accounts for approximately another 20 per-mosphere has begun to change at dramatically cent. CFCs are known to deplete the stratosphericaccelerated rates as a result of human activities. ozone layer; these stable and long-lived chemi-According to a growing scientific consensus, if cals are also extremely potent greenhouse gases.current emissions trends continue, the buildup of Deforestation and agricultural activities (espe-infrared-absorbing gases is likely to turn earth's cially rice production, cattle raising, and the usenatural atmospheric greenhouse into a progres- of nitrogen fertilizers) each contribute about
39 CHAPmER 4: ALVAnE Fuis
13-14 percent to global warming. mass-based fuels could reduce substantiallyAs greenhouse gases accumulate in the atmo- transportation's contribution to global warming.
sphere, they amplify the earth's natural greenhouseeffect, profoundly and perhaps irreversibly threat-ening humankind and the natural environment. ELECTRIC VEHICLESWhile most scientists agree on global warming'soverall features, considerable uncertainties still Environmental concerns have prompted the usesurround its timing, magnitude, and regional of electric vehicles (EV) in the United States andimpacts. The global climate system is complex, around the world. UNDP estimates that theand interactions between the atmosphere and the emerging and rapidly-growing EV market willoceans are still imperfectly understood. go from virtually zero in 1996 to US$2.5 billion
Two recent events have heightened this by 2000.5 In the United States, California hasconcern. In late November 1995, the Inter- mandated the target of 10 percent of its sales ofgovernmental Panel for Climate Change (IPCC) cars and light-duty trucks being zero emissionsWorking Group 1 concluded that "the balance of (almost certainly electric) by 2003.6 Many com-evidence suggests that there is a discernible panies have developed or are developing electrichuman influence on global climate." 2 More vehicles, some of which (particularly small ve-recently, a provisional report issued by the British hicles such as electric bicycles and motorcycles)Meteorological Office and the University of East can be used in the developing world.Anglia concluded that the earth's average surface Introducing electric vehicles in the develop-temperature climbed to a record high in 1995.3 ing world is sometimes advocated as an opportu-In spite of commitments by most industrialized nity to move to environmentally sustainable trans-countries to stabilize or reduce CO2 emissions, portation. There are several encouragingvery little progress has occurred in the examples in Asia. A demonstration fleet of elec-transportation sector. Recent strategies such as tric vehicles is already operating in Kathmandu,mandatory increases in fuel economy or Nepal.7 Electric three-wheelers ("tuk-tuks") aresubstantial increases in fuel taxes have proven being manufactured in Thailand.8 Electric mo-disappointing. Biofuels, giving off dramatically torcycles have been developed in Taiwan.9
lower CO2 emissions, are therefore emerging as USAID has been promoting electric vehicle tech-one of the more attractive and less painful nology in India.'" Similar projects have beenapproaches to lowering greenhouse gas proposed for Bangladesh.emissions. EV's life-cycle environmental characteristics
One seminal study released in late 1991 as- depend on the fuel used to produce the electric-sessed greenhouse gas emissions from a variety ity. Electric power based on hydropower or natu-of potential fuels; some of the results are sum- ral gas results in significantly reduced emissions.marized in figure 4.1.4 This study con'cluded that Some other fuels (especially coal) may actually'in considering total fuel cycle CO2 emissions (in- produce an increase in overall emissions if usedcluding not only direct vehicle emissions, but fuel to charge EV batteries, but still have the positiveproduction and distribution, feedstock produc- effect of localizing emissions."tion and distribution, and vehicle materials and EV technology is presently considered too ex-assembly), methanol and ethanol produced from pensive, although its promoters have expressedwood are among the two most attractive fuels ambitions for commercialization in both indus-available, exceeded only by solar power. Bio- trialized and developing countries.7 1
2 High costs
.
Figure 4.1: Greenhouse Gas Emissions from Fuels
8~~~~~~~~~at a ,, As e . ............................. ................................... ,...................................................... .
o Feed ProdJDist.
* Fwl ProdJDist
Vehide Bnissions
C. Af.
Source: U.S. Departme,t of Energy, 1991.
41 CHAPTER 4: AL7ERN4iThE FURLS
and short range (miles per charge) have limited ENDNOTESthe mass appeal of EVs. New developments inelectric battery technology are critical to 1. Derived from analysis prepared by Chrisprogress.1 3 Weaver. Faiz, A, C. Weaver and NMP. Walsh,
Along with battery-powered EVs, other op- November 1996. "Air Pollution From Motortions such as fuel cell technology, which con- Vehicles: Standards and Technologies For Con-verts fuel energy directly into electricity without trolling Emissions." Sacramento, CA: Engine,combustion,1 4 appear very promising but are even Fuel, and Emission Engineering, Incorporated.more expensive at present. EVtechnology's po- 2. U.S. Environmental Protection Agency.tential to reduce greenhouse gas emissions has Spring 1997. Inside the Greenhouse, USEPAbeen recognized in the Global Environmental State and Local Climate Change Program, p.Facility's new Transport Sector Operational 1. Washington, DC.Programme."5 3. Airey, M.J., M. Hulme, and T.C. Johns. 1996.
"Evaluation of Simulations of Terrestrial Pre-cipitation by the U.K. Met. Office Hadley
FACTORS INFLUENCING LARGE-SCALE USE OF Centre Model," Geophysical Research Letters,ALTERNATIVE FUELS 23(13): 1657-60.
4. Delucchi, Mark. Emissions of Greenhouse1 . Introducing alternative fuels requires changes Gases from the Use of Transportation Fuels
in distribution, marketingp and end-use systems. and Electricity, Volume 1, ANL/ESD/TM-22.2. Apart from the economics, inadequate fuel Argonne National Laboratory, Department of
supply or unreliable distribution systems could Energy, 1991.adversely affect consumer acceptance of al- 5. 7he Financial Times, April 8, 1997.ternative transportation fuels. 6. CALSTART News, http://www.calstart.org/
3. Experience with the use of ethanol in Brazil news/newsnotes/96032903.html.and CNG in New Zealand suggests that the 7. Faiz, A., C. Weaver, and M. Walsh. 1996. "Airmain factors influencing large-scale introduc- Pollution From Motor Vehicles: Standards andtion of CNG and alcohol fuels are price com- Technologies for Controlling Emissions."petitiveness, feedstock availability and cost Washington, DC: World Bank.(e.g., sugar cane for ethanol or natural gas for 8. Communication with the World Bank Resi-CNG), fuel safety and quality standards, a re- dent Mission in Bangkok, April 1997.liable distribution system, and the vehicles' 9. Chen, Hsiung-Wen. "Development of the Elec-technical quality (driveability, durability, and tric Motorcycle in Taiwan." Presentation atsafety). the World Bank. Environmental Protection
4. Brazil's use of ethanol and New Zealand's use Agency: Taiwan (China).of CNG demonstrate that it is possible to de- 10. USAID India and Energy Technology Inno-velop a large alternative fuels market within a vation Project. January 1997. "Electric Vehiclereasonable time frame if the financial incen- Investment Opportunities in India."tives are favorable, and efforts are made to 11. OECD/IEA. 1993. "Cars and Climateovercome industry and consumer uncertainty. Change". p. 94-95.In both instances, substantial subsidies had to 12. Sperling, D. Winter 1994-95. "Gearing upbe offered to private motorists to persuade for electric cars," Issues in Science and Tech-them to switch to alternative fuels. nology, p. 33-41.
CLEAN FuELs FOR ASA: TECHNICAL OP77ONS FOR MOvNG TOwARDs UNEADED GASOLINE AND Low-SULFUR DIESEL 42
13. Aragane,J.March1997. "OverviewofAdvanced tion Systems". Presentation at the STAPBatteries Technologies forEV Applications in Workshop on Transportation, Nairobi, Kenya.Japan" Tokyo, Japan: Lithium BatteryEnergy 15. STAP/GEF. March 14-15, 1997. "Report onStorage Technology Research Association the STAP Workshop on Options for Mitigat-
14. Williams, R. March 14, 1997. "Opportuni- ing Greenhouse Gas Emissions from theties for Electric Drive Vehicles in Coping with Transport Sector," p. 6-7.the Multiple Problems Posed by Transporta-
CHAPTER 5:IMPLEMENTING A CLEAN FUELS PROGRAM
Implementing a clean fuels program can take ample, all stations might be required to providemany forms, including strict government man- at least one grade of unleaded gasoline by a de-dates, fiscal incentives, or some combination of fined date. Refinements of this approach mightthe two. Mandates can focus on fuel quality, ve- limit this to only stations pumping a certain vol-hicle fuel requirements, or ifuel pump nozzles. ume of fuels. Another approach would requireSome of the more common approaches are sum- all regular-grade fuel of a certain octane to bemarized below (figure 5.1). unleaded, while allowing the premium grade to
remain leaded. Bangkok chose this approach forits clean fuel program by requiring all gasoline
IMPROVING FUEL QUALITY to be unleaded by 1996.
Perhaps the simplest and most direct approach isto rule that some or all grades of fuel meet spe- VEHICLE FUEL REQUIREMENTS
cific characteristics by a certain date. For ex-Another approach requires that all new vehiclesfrom a specified date onward only be allowed touse fuels meeting certain characteristics (e.g.,
Figure 5.1: Implementing a Clean Fuels unleaded gasoline). This approach has beenProgram implemented in Singapore, where all new cars
are required to operate on unleaded gasoline. Thisaddresses any concerns about valve seat reces-sion and soft valve seats, and eliminates lead
uel Pump emissions from these vehicles. For detailed in-Nozzle formation regarding international fuel emissions
standards, see appendix D.
Clean-/ Taxes for Vehicle Fuel\Clean Fuels Fuels Requirements FUEL PUMP NOZZLE CHARACTERISTICS
As noted earlier, vehicles equipped with catalyticconverters require unleaded gasoline to ensure
Fuel that these systems are not destroyed. When leadedQuality gasoline is cheaper than unleaded, the chances
of misfueling are high. To prevent such vehiclesfrom being deliberately or inadvertently fueledwith leaded gasoline, cars with catalytic convert-
43
CAN FusL FOR ASA: TEccAL OPnoNs FOR MoVN TowARDs UNEADED GAsoLNE AND Lo w-SUUR DiESEL 44
ers canbe equipped withfiller inlet restrictors or Figure 5.2: Elements of a Comprehensive Vehicle Pollutiondesign changes that do Control Strategynot allow leaded fuelnozzles to fit. While Athis is by no means a VEHICLEfail-safe approach, it is ECHNOLOGY
definitely a step in theright direction.
XAPPROPRIATE\ / TRAFFICADOPTING CLEAN M DTA MANAGEMENT
FUEL TAX INCENTIVES MNG
Rather than directlymandating unleaded CLEANgasoline or low-sulfur FUELS
diesel fuel, or in addi-tion to this step, many Igovernments have in-troduced tax policies intended to give the cleaner translated into strategies that lower emissions perfuel a lower market price than the dirtier fuel. kilometer driven and reduce actual driving. BothTheoretically, public demand will then assure the approaches can be used to lessen future air pol-cleaner fuel's availability and use. This strategy lution damage in Asian cities.can be used in the absence of a sales mandate or Generally, a motor vehicle pollution controlas a complement to accelerate clean fuel's mar- program's goal is to reduce vehicle emissions toket penetration. Hong Kong provides one of the a degree necessary to achieve healthy air as rap-most successful examples of this incentive. idly as possible. This should be accomplished
Experience shows that fuel pricing must play a within practical technological, economic, andkey role in any strategy to encourage cleaner fu- socially feasible limits. This goal generally re-els. For example, in the United States during the quires a comprehensive strategy encompass-1970s and early 1980s, leaded gasoline was con- ing new vehicle emissions standards, cleanersistently less expensivethanunleaded As a result, fuels, vehicle maintenance, and traffic andin spite of fuel nozzle size restrictions and vehicle demand management and constraints. Thesefuel filler inlet restrictions, many people destroyed emissions reduction goals should be achieved intheir catalytic converters by using leaded fuel. the least costly manner. Exhaust and evapora-
tive motor vehicle emissions standards should bebased on a realistic cost-benefit analysis, keep-
VEHICLE POLLUTION CONTROL EFFORTS ing in view proposed countermeasures' techni-UNDERWAY IN AsIA cal and administrative feasibility.
A great deal has been learned about reducing ve- The following technological approaches' mayhicle emissions, and this knowledge has been be used to achieve desired emissions standards:
45 CHAPTER 5: IMPLEMENN7NG A CLEAN FUELs PROGRAM
* fitting new vehicles withi emissions control air quality problem, as the traffic volume is thedevices and requiring such devices to be ret- same. However, the peak hours may be longer;rofitted to existing vehicles; thus the longer averaging time (8-hour) may pro-
* modifying fuels or requiring the use of alter- duce stable or increasing results. The high val-native fuels in certain vehicles; and ues observed for the 8-hour averages are about
* traffic and demand management and policy 20 mg/m3 . Similarly, curbside 8-hour averageinstruments. concentrations of CO are close to and sometimesHowever, many of these measures' potential exceed Thai standards (20 mg/m3 ). Concentra-
benefits will be lost if they are not buttressed by tions as high as 25 mg/m3 have been recorded.regulatory and economic instruments that assure A U. S. Agency for International Developmentthat vehicle owners, manufacturers, and fuel sup- (USAID) study (1990) attempted to rank envi-pliers have sufficient incentives to achieve the ronmental health risks to Bangkok's 5.5 milliondesired goals. A key element of the overall residents. It was estimated that 270,000 peoplestrategy, therefore, must be effective enforce- are at moderate risk for health effects associatedment to ensure adequate compliance with with CO (angina in people with chronic cardio-standards. vascular disease), and 1.3 million people at mild
Several jurisdictions in Asia have successfully risk (inability to concentrate and headaches forimplemented some or all of these strategies. Spe- people in the general population).3
cific examples in Hong Kong, Singapore, South A World Bank study (1992) indicates that ifKorea, Taiwan, and Thailand illustrate some of Bangkok's ambient concentrations of SPM andthese efforts. lead were reduced by 20 percent from 1992 lev-
els, the midpoint estimates of the annual healthBangkok, Thailand benefits from less sickness would be US$1 to 1.6
billion. Benefits in terms of lower mortalityIn response to the serious air pollution threat, would amount to between US$300 million andThailand's Seventh Plan has placed a high prior- 1.5 billion. The study assigned various monetaryity on improving air quality. Definite targets have values to the estimated health risks found by thebeen set to control particulates (SPM), carbon USAID study, and estimated an economic ben-monoxide (CO), and lead in Bangkok. Based ona efit of US$10.7 million annually from CO re-careful review of available air quality data, it is duction in Bangkok.4
estimated that roadside emissions of particulates,CO, and lead must be reduced by 85 percent, 47 Bangkok's current program. A number ofpercent and 13 percent, respectively, if Bangkok measures have been adopted to mitigate air pol-is to achieve acceptable air quality.2 To date, there lution problems caused by the transport sector.is no evidence of an ozone or nitrogen dioxide These are aimed not only at controlling exhaust(NO2) problem. However, since certain hydrocar- gas emissions, but also at improving fuel andbons are known to be toxic, it is prudent to adopt engine specifications, implementing an in-usemeasures thatwill reduce these emissions as well. vehicle inspection and maintenance program,
One-hour concentrations of CO in congested improving public transport through mass transitstreets have been on the decline since 1992, but systems, and improving traffic conditions through8-hour averages have not similarly declined. This better traffic management.suggests that during peak traffic hours new cars The following measures have been introducedand emissions control technology may lessen the to reduce vehicle emissions:
CLEAN FUFLSFOR ASI: TECHNICAL OPTONSFORMMOnNG TowARDs UNLEADED GAsoLINE AND Low-S1AFuR DIEsL 46
1. Introducing unleaded gasoline at prices lower and rental vehicles) are subject to inspection dur-than leaded gasoline (effective May 1991). ing annual registration renewals. It is expected
2. Reducing the maximum allowable lead in that the LTD will soon require all in-use vehiclesgasoline from 0.4 to 0.15 grams per liter (ef- to be inspected. Private inspection centers are be-fective January 1, 1992). Ambient lead levels ing licensed. Vehicles in use for ten or more yearshave declined in recent years due to reduced are subjected to an annual inspection, while newerlead content in gasoline and the increased use vehicles will be subjected to inspection at differ-of unleaded gasoline. ent time periods, to be determined by the LTD.
3. Phasing out leaded gasoline entirely (January1, 1996). Future Plans. Further investigations underway
4. Reducing the sulfur content of diesel fuel sul- will introduce more stringent standards for mo-fur from 1.0 to 0.5 percent by weight (by April torcycles and light and heavy trucks, and lead to1992 in the Bangkok Metropolitan Area, and the further purchase of compressed natural gasnationwide after September 1992); and mak- (CNG) buses to reduce the smoke problem.ing the use of low-sulfur diesel fuel manda- As a comprehensive motor vehicle pollutiontory in Bangkok (since September 1993). control strategy has been introduced in Bangkok,
5 . Reducing the diesel fuel T90 from 370°C to the most critical data needs appear to be those re-35 7C (by April 1992 in the Bangkok Metropoli- lated to motorcycle and diesel vehicle particulatetan Area, and nationwide after September 1992). emissions factors. In addition, as the new air qual-
6. Requiring all new cars with engines larger than ity monitoring network is deployed it will be criti-1600 cubic centimeters to meet ECE R-83 cal to periodically update the air quality targets.standards (effective January 1993); and all carsrequired to comply after September 1993. Conclusions. Bangkok, like many other
7. Converting taxis and Tuk-Tuks to operate on megacities, has serious air pollution problemsliquefied petroleum gas (LPG). associated with energy use in the transport sec-
8. Introducing ECE R40 requirements for mo- tor. Several factors, including population growthtorcycles (effective August 1993), followed and rapid economic expansion, are fundamentalsoon afterward by ECE R40.01; the govern- issues that need to be addressed in any long-termment then decided on a third level of controls planning. Rapid industrialization and urbaniza-which began to be phased in during 1995. tion, coupled with a previous lack of land-use
9. Implementing ECE R49.01 standards for planning, have contributed to atmospheric pol-heavy-duty diesel engine vehicles. lution associated with the transport sector. This
l0.Reducing diesel fuel sulfur levels from the problem has been intensified by inadequate roadcurrent 0.5 percent by weight to 0.25 (by infrastructure for the rapidly growing vehicle1996), and 0.05 by the year 1999. population, and the lack of a mass transport sys-Currently, noise and emissions testing is man- tem to offer a viable substitute for private ve-
datory under the Land Transport Department's hicles. These factors tend to push people to rely(LTD) general vehicle inspection program. All more on their private vehicles (contributing tonew vehicles are subject to such inspection. Of congestion), rather than drive less.in-use vehicles, only those vehicles registered It is recognized that this problem can be alle-under the Land Transport Act (buses and heavy- viated through several measures: source reduc-duty trucks) and commercial vehicles registered tion through improvement of fuel quality, inspec-under the Motor Vehicles Act (taxis, Tuk-Tuks, tion and maintenance programs, vehicle standards,
47 CHAP [ER 5: IMPeLMENIING A CLEAN FunEs PROGRAM
and traffic and demand management (including works closely with the Registry of Vehicles toa good mass rapid transit system). A great deal implement this strategy.of policy work needs to be done to understand * During 1981-87, the lead content of gasolinetravel demand (demand-side management). was gradually reduced from 0.8 to 0.15 grams
per liter. Theuse of unleaded gasolinewas pro-Singapore moted in February 1990 through a differential
tax system that made unleaded gasoline S$0. 10In Singapore, motor vehicle emissions are a sig- cheaper per liter than leaded gasoline at thenificantsourceofairpollution. Thevehiclepopu- pump. All gasoline-driven vehicles registeredlation has been steadily increasing over the past for use in Singapore after July 1991 were re-decade as a consequence of rapid urbanization and quired to use unleaded gasoline. These mea-economic growth. At the beginning of 1993, the sures resulted in the greater use of unleadedmotor vehicle population stood at approximately gasoline. About 57 percent of all gasoline sold550,000. Singapore's Clean Fuels Program has in Singapore by the end of 1993 was unleaded.eight major components: land transport policy, * The sulfur content in diesel fuel was first lim-mobile source controls, traffic management mea- ited to 0.5 percent by weight, and has been re-sures, vehicle registration and licensing, a vehicle duced to 0.3 percent by weight since July 1996.quota system, the weekend car scheme, the area * Motor vehicle emissions standards have beenlicensing scheme, and public transportation. progressively tightened since 1984, and the
standards currently in force are the EuropeanSingapore's land transport policy strives to pro- Union Consolidated Emissions Directive 91/vide free-flowing traffic within the constraints of 441 and Japanese emissions standards (Articlelimited land. A four-pronged approach has been 31 of Safety Regulations for Road Vehicles)adopted to achieve this objective: (see appendix D).1. Minimizing the need to travel, through sys- * Since October 1992, motorcycles and scoot-
tematic town planning. ers have been required to comply with U.S.2. Building an extensive and comprehensive emissions standards before they can be regis-
network of roads and expressways, augmented tered for use in Singapore.by traffic management measures, to provide * SinceJanuary 1991, all dieselvehicleshavebeenquick accessibility to all parts of Singapore. required to comply with smoke standards stipu-
3. Promoting a viable and efficient public trans- lated in UN/ECE Regulation No. 24.03 beforeport system, integrating both the Mass Rapid they can be registered for use in Singapore.Transit (MRT) and bus services. * All in-use vehicles are required to undergo
4. Managing the number and operation of ve- periodic inspections to check their roadwor-hicles to prevent congestion on the road. thiness and idling exhaust emissions. Vehicles
that fail inspection are not allowed to renewMobile Source Controls. Singapore's strategy their road tax.to reduce pollution from motor vehicles is a two-pronged approach. The first is to improve en- Traffic Management Measures. Singapore, agines and fuel quality to reduce emissions; and city-state with a large population living on a smallthe second is to use traffic management measures land mass, is unique in many ways. Urbaniza-to control the vehicle population and fuel con- tion, industrialization, and infrastructural devel-sumption. The Pollution Control Department opment are still progressing in earnest, fueled by a
CiLsE FUFs FOR ASIA: TECHNICAL OPnoNs FOR MOVING TOwARDs ULEADED GASOUINE AND Low-SULFUR DIESEL 48
growing economy. This combination of factors any person wishing to register a motor vehicleshows apotential forserious environmental prob- must first obtain a vehicle entitlement in the ap-lems from both stationary and mobile sources, if propriate vehicle class, through monthly bidding.the sources are not managed or controlled prop- Successful bidders pay the lowest successful biderly. Theneedtomanagetrafficflowhasgivenrise price of the respective category in which theyto a unique set of traffic management measures. bid. A vehicle entitlement is valid for ten years
from the vehicle's registration date. On theVehicle Registration and Licensing. The ex- entitlement's expiration, if the owner wishes topense of owning and operating a vehicle in Sin- continue using the vehicle, the entitlement mustgapore has discouraged excessive growth in the be revalidated for another five or ten years byvehicle population. Car owners wishing to regis- paying a revalidation fee (pegged at 50 percentter their cars must pay a 45 percent import duty or 100 percent of the prevailing quota premium).on the car's open market value (OMV), a regis-tration fee of S$1,000 for a private car (S$5,000 Weekend Car Scheme. The weekend car schemefor a company-registered car), and an Additional was introduced in May 1991 to allow people toRegistration Fee of 150 percent of the OMV. own private cars without adding to traffic con-
In addition, car owners pay annual road taxes gestion during peak hours. Cars registered underbased on the vehicle's engine capacity. Road tax this scheme enjoy substantial tax concessions,on company-registered cars is twice as high as including a 70 percent reduction in road tax andfor privately-owned vehicles. Diesel vehicles are a registration tax rebate of up to S$15,000. Week-charged a tax six times greater than the road tax end cars are identified by their red license plates,on an equivalent gasoline vehicle. fixed in place with a tamper-evident seal. They
To encourage drivers to replace their old cars can only be driven between 7 p.m. and 7 a.m.with newer, more efficient models, a Preferen- during the week, after 3 p.m. on Saturdays, andtial Additional Registration Fee (PARF) system all day on Sundays and public holidays. Week-was introduced in 1975. Private car owners who end cars can be driven outside those hours butreplace their cars within ten years are given PARF owners must display a special day license. Eachbenefits that can be used to offset a new car reg- weekend car owner is given five free day licensesistration fee. For used cars registered on or after per year and can buy additional ones at S$20 each.November 1, 1990, PARF benefits vary accord-ing to the age of the vehicle at deregistration. The Area Licensing Scheme (ALS) was intro-For cars registered before November 1, 1990, a duced in June 1975 to reduce traffic congestion infixed PARF benefit is given upon deregistration the city during peak hours. At that time it only af-based on the car's engine capacity. To provide a fected passenger cars. The scheme has since beenhigher PARF benefit to car owners who deregister modifiedto include allvehicles except ambulances,their cars before ten years, all PARF-eligible cars fire engines, police vehicles, and public buses.registered on or after November 1990 receivehigher fees if the vehicle is newer. PublictransportationinSingaporeiswidelyavail-
ableandincludesamassrapidtransit(MRT)system,Vehicle Quota System. As high taxes alone were acomprehensivebusnetworkandoverl3,000taxis.not keeping vehicle population growth at an ac-ceptable rate, a vehicle quota system was intro- Conclusions. Aside from regulations on enginesduced to achieve that objective. Since May 1990, and fuel quality, traffic control measures have
49 CHArPER 5: IMPLEMEN2ING A CLEAN FUELS PROGRAM
significantly contributed to Singapore's air qual- starting April 1997.ity. Although the present measures appear ad- Encouraged by a price differential of HK$1equate, Singapore will continue to investigate per liter for unleaded gasoline as compared tomore improvements. Pilot studies of three elec- leaded, by 1997 unleaded gasoline representedtronic road pricing systems are being carried out 80 percent of total gasoline sales. The benzenein Singapore, and the most suitable system will content of unleaded gasoline is only 3.44 per-be selected for implementation in 1997. cent, virtually the same as leaded gasoline (regu-
lation requires it to be less than 5.0 percent).Hong Kong, China
Future Plans. An analysis of motor vehicle-re-Hong Kong's vehicle pollution control effort lated urban particulates indicates that 14 percentcontinues to focus on diesel particulate, currently come from buses, 33 percent from goods vehicles,the most serious pollution problem. Motor ve- 51 percent from diesel vehicles weighing underhicles are said to be responsible for approximately 4.0 tons, and the remaining 2 percent comes from50 percent of PMIO emissions (see appendix D). gasoline vehicles.
* As a matter of policy, Hong Kong is lookingCurrent Program. The sulfur level of diesel fuel for ways to reduce diesel vehicle mileage. Ahas been reduced to 0.2 percent by weight (as of government working group has been formedApril 1995), and there are plans to lower it to to study the technical feasibility of natural gas0.05 percent (April 1997). vehicles. The short-term focus is on LPG-fu-
Diesel vehicle emissions standards were also eled taxis, while other natural gas vehicles aretightened in April 1995. After that date, all new being investigated.passenger cars and taxis were required to com- * Advancement in new technologies, such asply with 1990 U.S. standards (PM = 0.12 grams electrical vehicles, are also being monitoredper kilometer, NO. = 0.63), European Union Step closely. The Government has waived the FirstI standards (93/59/EEC PM = 0.14, HC + NO, = Registration Tax (which can amount to as0.97), or Japanese standards (PM = 0.34, NO = much as 50 percent of a vehicle's price) tox0.72 for vehicles weighing less than 1.265 tons encourage the introduction of electrical ve-or 0.84 for those above). Similar requirements hicles into Hong Kong.will apply to all light and medium goods vehicles * The government plans to implement an in-and light buses. Emissions standards for small spection and maintenance program for dieseldiesel vehicles will be tightened to EURO 2 stan- vehicles in the near future.dards staring April 1998 (96/69/EMPM 0.08 and * Hong Kong also remains interested in the pos-0.10, HC + NOX = 0.7 and 0.9 for indirect injec- sibility of retrofitting buses with either emis-tion and direct injection engines, respectively). sions catalysts or diesel particulate filters.For goods vehicles and buses with a design weightof 4.0 tons or more, starting April 1997, either South Koreathe 1994 U.S. standards (PM = 0.13 grams perkWh, NOx = 8.04) or the EURO 2 standards (PM A series of recent amendments in the Air Qual-= 0.15; NOX = 7.0 for all engines) will apply. ity Control Law will gradually tighten South
The in-use smoke limit, now based on the EEC Korea's vehicle emissions standards, as summa-free acceleration test (72/306/EEC), was 60 HSU; rized in tables 5.1 and 5.2.in certification, the limit was lowered to 35 HSU Diesel fuel sulfur levels were reduced to a
CLE4 FU5Ls FOR ASIA: TEcHImcAL OP77ONS FOR MoI7NG TOwARDs UMNADED GASOLLINE AND LoW-SULFUR DIESEL 50
Table 5.1: South Korea: Emissions Standards For New Gasoline and LPG Vehicles
Vehicle Type Date Of Implementation Test CO NOx Exhaust HC Evap HC (gltest)
Small Size 1987 7/1 CVS-75g/km 8.0 1.5 2.1 4.0
Car* 2000 7/1 CVS-75 2.11 0.62 0.25 2.0
Passenger Car 1980 1/1 10-Mode 26.0 3.0 3.8
1984 7/1 10-Mode 18.0 2.5 2.8
1987 7/1 CVS-75 2.11 0.62 0.25 2.0
2000 1/1 CVS-75 2.11 0.25 0.16. 2.0
Light Duty 1987 7/1 CVS-75 6.21 1.43 0.50 2.0
Truck** 2000 1/1 CVS-75@ 2.11 0.62 0.25 2.0
2000 1/1 CVS-75@@ 6.21 1.43 0.50 2.0
Heavy Duty 1980 1/1 6-Mode 1.6% 2200 ppm 520 ppm
Vehicle 1987 7/1 U.S. Transient 15.5 10.7 1.3 4.0
19912/1 13 Mode 33.5 11.4 1.3
2000 2/1 13 Mode 33.5 5.5 1.4
Notes:
Less than 800 cc of Engine Displacement GVW < 3 tons
@ GVW < 2 Tons @@GVW Between 2 and 3 Tons
Source: Based on discussions with Kang Rae Cho, 1996.
maximum of 0.4 percent by weightbetween Feb- to motor vehicle pollution control. Building onruary 2, 1991 and December 31, 1992; to 0.2 its early adoptionof 1983 U.S. standards forlight-during January 1, 1993-December 31, 1995; and duty vehicles (starting July 1, 1990) it recently0.1 thereafter. Korea is also investigating pos- moved to 1987 U.S. requirements, including thesible improvements to their inspection and main- 0.2 grams of particulates per mile standard, as oftenance (I/M) program, including the possible ad- July 1, 1995. Heavy-duty diesel particulate stan-dition of the IM240 test procedure. dards almost as stringent as 1990 U. S. emissions
There is ongoing research in the use of diesel standards (6.0 grams per brake horsepower-hourparticulate filters. On-road testing of prototype NOX and 0.7 grams of particulate, using the U.S.systems in operating buses is presently under transient test procedure) became effective Julyevaluation. 1993. InJuly 1997, 1994 U.S. standards (5.0 NO.
and 0.25 particulates) will be adopted. CurrentlyTaiwan (China) diesel fuel contains 0.3 percent by weight of sul-
fur, and a proposal to reduce levels to 0.05 per-The Taiwan Environmental Protection Agency cent by 1997, is under consideration.(TEPA) has developed a comprehensive approach In December 1992, the Executive Yuan ap-
51 CHAP7ER 5: IAPLEMENi7NG A CLEAN FuFIs PROGRAM
Table 5.2: South Korea: Emissions Standards For New Diesel Vehicles
Vehicle Type Date of Implementation Test CO NOx HC PM Smoke
Passenger Car 1980 1/1 Full Load - - 50%
1984 7/1 6-Mode 980 ppm 1000/590* 670 50%
1988 1/1 6-Mode 980 850/450 670 - 50%
1993 1/1 CVS-75 2.11 0.62 0.25 0.12 -
1996 1/1 CVS-75 2.11 0.62 0.25 0.08
2000 1/1 CVS-75 2.11 0.62 0.25 0.05 -
Light Duty 1980 1/1 Full Load - - - - 50%
Truck** 1984 7/1 6-Mode 980 1000/590 670 - 50%
1988 1/1 6-Mode 980 850/460 670 - 50%
1993 1/1 6-Mode 980 750/350 670 - 40%
1996 1/1 CVS-75 6.21 1.43 0.5 0.31(0.16)@ -
Light Duty 2000 1/1 CVS-75 2.11 0.75 0.25 0.12Truck < 2 Tons
All Other Light 2000 1/11 CVS-75 6.21 1.00 0.5 0.16 -
Duty Trucks
Heavy Duty 1980 1/1 Full Load - - - - 50%
Vehicle 1984 7/1 6-Mode 980 1000/590 670 - 50%
1988 1/1 6-Mode 980 850/450 670 - 50%
1993 1/1 6-Mode 980 750/350 670 - 40%
1996 1/1 13-Mode 4.9 11.0 1.2 0.9 35%
2000 1/1 13 Mode 4.9 6.0 1.2 0.25 (.1@@) 25%
Notes:
* Direct Injection/Indirect Injecton GVVV < 3 tons
@ GVW < 2 Tons @@ City Bus Only
Source: Based on discussions with Kang Rae Cho, 1996.
proved increases of up to 1,700 percent for the in the new fine schedule, including airplanes,amount of fines to be levied on motorists who boats, and power water skis. The new fines tookviolate the Air Pollution Control Act. The new effect early in 1993.fine schedule raises the maximum motor vehicle Clearly, the most distinctive feature ofpollution fine from NT$138 to NT$2,357. All Taiwan's program is its motorcycle pollutionforms of motorized transportation are included control effort, which reflects just how much
CL.EAY FUELS FOR As: TECHNICAL OP7ONS FOR MOViNG TowARDs UNLEADED GASOLiNE AND LOw-SuLFUR DIESEL 52
motorcycles dominate the vehicle fleet, and the durability requirement will be raised to 20,000extent of the resulting emissions. kilometers. The market share for electric-pow-* The first standards for new motorcycles were im- ered motorcycles will be mandated at S per-
posed in 19848.8 grams per kilometer for CO, cent. In addition, TEPA will extend the peri-and 6.5 grams per kilometer for HC and NOX odic motorcycle I/M program.combined, using the ECE R40 test procedure.
* In 1991, the limits were reduced to 4.5 gramsof CO per kilometer, and 3.0 for HC and NOX COMPREHENSIVE PROGRAMS: THE UNITEDcombined. These requirements were phased STATES EXPERIENCEin over a two-year period, and by July 1993,were applied to all new motorcycles sold in Since 1970, the United States has adopted anTaiwan. As a result of these requirements, aggressive strategy to reduce auto emissions andfour-stroke motorcycle engines have been re- improve air quality. This strategy has manydesigned to use secondary air injection, and elements, including unleaded gasoline, tighterall new two-stroke motorcycles are now fit- standards for new vehicles, in-use vehicleted with catalytic converters. inspection and maintenance programs, and most
* Since 1992, electric motorcycles have been recently, reformulated and low-volatilityavailable; however, sales have been modest. gasoline. As a result, over the past 25 years, on-
* Motorcycle durability requirements were im- highway cars' emissions rates have declinedposedin 1991. All newmotorcycles arerequired dramatically. As newer vehicles equipped withto demonstrate the ability to meet emissions advanced emissions controls replaced older,standards for a minimum of 6,000 kilometers. more-polluting ones, there has been a clear
* Since 1991, all new motorcycles must be downward trend in emissions of all majorequipped with evaporative controls. pollutants. This is especially encouraging in light
* Inordertoreducethepollutionfrommotorcycles, of the continued rapid growth in vehicles andTEPA is actively promoting a motorcycle in- vehicle-miles traveled by cars during this samespection and maintenance (JIM) system. In the period. There were 50 million more cars on U.S.first phase (February-May 1993), TEPAtested highways in 1990 than in 1970. Had emissionsapproximately 113,000 motorcycles in Taipei per mile not been lowered, passenger cars in 1990City. Of these, 49 percent were clean, 21 per- would have emitted 65 percent more CO, HC,centweremarginal,and30percentfailed. and NOx than in 1970. In other words, as
* Between December 1993 and May 1994, ap- illustrated in table 5.3, passenger car CO wasproximately 142,000 motorcycles were in- reduced from 68 million metric tons to 27, insteadspected with 55 percent passing (up 6 percent of climbing to 112 tons.from theearlierprogram), and 27 percent failed Figure 5.3 illustrates auto emissions reductions(dropping 3 percent). The most common re- to date: 60 percent for CO; 70 percent for HC;pair for failing motorcycles was replacement and 46 percent for NOX. Lead emissions from allof the air filter, at an average cost of NT$20. highway vehicles have also been reduced dra-
* To further control motorcycle emissions, TEPA matically, and between 1970 and 1993, highwayhas drafted the Third Stage Emissions Regu- vehicle lead emissions declined from 171,960 tolation, to be implemented from 1998. The new 1,380 shorttons. This example best illustrates thatstandards will lower CO to 3.5 grams per kilo- a strong motor vehicle pollution control programmeter, and HC plus NOX to 2 grams, and the can be effective.
53 CHAP=ER 5: IMPLSMEN2NVG A CLEAIv FuEtS PROGRAM
CONCLUSIONS capabilities of a particular country or city-one size does not fit all.
As the above examples illustrate, substantial ef- * In virtually every serious effort to reduceforts to address motor vehicle pollution have been motor vehicle pollution, cleaner fuels, espe-made and are continuing throughout many Asian cially unleaded gasoline and lower-sulfur die-countries. Several conclusions can be drawn from sel fuel, have played a critical role.these efforts:* Therearemanycom-
prehensivemotorve- Table 5.3: Emissions Trends In The United States (1970-90):hicle pollution con- Passenger Cars (tons per year)trol programs in theAsiaregion. Carbon Monoxide Hydrocarbons Nitrogen Oxides
* A wide variety of 1970 Actual 67.9 8.87 4.36strategies have been 1990 Actual 26.9 2.65 2.34implemented andtailored to the par- 1990 Potential* 112.0 14.6 7.2ticular problems and *What would have occurred had pollubon controls not been required durng this perod.
Source: Based on the USEPA Mobile 5 Model.
Figure 5.3: Trends in Emissions from U.S. Cars (normalized to 1970 levels)
2001"-.ONMETHANE HYDROCARBONSi "ARBON MONOXIDE- NITROGEN OXIDES
150i VEHICLE MILES TRAVELLED
100 _
Sore ra .e based on. the :S:.A Mobile 5: Em:: sio:: Mod
... :::: :: . . . .::::::-::::::::::::: ::::::::::::-:::.::::::::::.::::: ::: ::::::::.:. :: 1.
1~~~~~~~~~~~~~~~~~~~~~~~~~~~.. ... .. . ....- - --.. 1 . ... ... ... ... ... ... ...5 0I v. .. ... .. ... 8--- 1 9 8 --- ----- -- ---- -... ... .... .... ...
sourceCreate base on th USEP Mobil 5 EmssionsModel
CL.EAN FuELs FOR AslA: TCIcHAL OP2ONS FOR MOVING TowARDs UJNADED GASOLINE AND LOW-SuLFUR DIESEL 54
ENDNOTES sources, to achieve the required overall emis-sions reduction.
1. See appendices B and C for a review of gaso- 3. U.S. Agency for International Development.line- and diesel-fueled vehicle pollution con- "Ranking Environmental Health Risks introl technologies, respectively. Bangkok, Thailand," Vols. 1 & 2, Working Pa-
2. These emissions, especially particulates, come per, 1990.from many sources in addition to mobile 4. E. Shin et. al. "Economic Valuation of thesources, which will need to be controlled as Urban Environment with Emphasis on Asiawell. It is assumed in this first order analysis and Non-Productivity Approaches," draft Pa-that the same percentage reduction will be per prepared for UNDP/World Bank/UNCHSneeded from all sources, including mobile Urban Management Program, 1992.
CHAPTER 6:
CONCLUSIONS AND RECOMMENDATIONS
In the last decade, Asian cities have undergone a (b)In every serious effort to reduce motor ve-tremendous growth in industrial output and hicle pollution, cleaner fuels-especially un-vehicle population. This growth has worsened air leaded gasoline and lower-sulfur diesel fuel-pollution in metropolitan areas, and unless have played a critical role.corrective actions are taken to improve the current 3. A growing body of data on lead's adverse ef-air quality situation, environmental damage and fects on health, especially in young children,human health impacts will undermine economic indicates there may be no "safe" level. Reducedgrowth. Motor vehicle pollution is a primary lead in gasoline has been shown to reducecontributor to air pollution in all the major cities children's risk of behavioral problems, lowerin Asia. There is considerable evidence that IQs, decreased ability to concentrate, and fortighter emissions standards in new cars, adults, blood pressure-related health issues.oxygenated and reformulated gasoline, and 4. Lead scavengers that accompany leaded gaso-alternative fuels will help reduce vehicular line have been identified as human carcino-emissions. Nevertheless, a number of obstacles gens; eliminating gasoline lead will also re-must be overcome before these changes can be duce this cancer risk.put into place on a large enough scale to make a 5. Studies in Europe and the United States showmeasurable difference in air quality. This report that gasoline lead is responsible for about 90provides technical options for implementing a percent of airborne lead, and that 1 microgramclean fuels program in Asia. per cubic meter of ambient lead causes a 1-2
microgram per milliliter increase in blood leadlevels. This is in addition to lead that may be
CONCLUSIONS found in food, drinking water, and othersources. This burden can vary significantly
1. Because motor vehicle populations in most from country to country.Asian cities continue to grow at rates often 6. Hydrocarbons (HC), carbon monoxide (CO),exceeding 10 percent per year, serious air pol- nitrogen oxides (NO.), and particulate matterlution problems can be expected in the future. cause or contribute to a wide range of adverse
2. Many Asian countries are making substantial impacts on public health and general well-be-efforts to address their motor vehicle pollu- ing, including increased angina attacks in vul-tion problems. Several conclusions can be nerable individuals; greater susceptibility todrawn from these efforts: respiratory infection; more respiratory prob-
(a) A wide variety of strategies are being imple- lems in school children; increased airway re-mented, often tailored to a particular city or sistance in asthmatics; and eye irritation. Fur-country's problems and capabilities. There is thermore, these emissions are known to impaira recognition that "one size does not fit all." crop growth and destroy lakes and forests. In
55
CLEAN FUELS FOR AsA: TECHNACAL OPn70NS FOR MO VING TowARDs UNLEADED GASOLINE AND Lo w-SuLFUR DIESeL 56
addition to their direct adverse health effects, vehicle emissions. Raising the cetane numberHC and NO contribute to the formation of appears to have positive impacts on emissions.photochemical smog and ozone, known to 13. Some alternative fuels, such as natural gas,cause many adverse effects. do offer the potential for large, cost-effective
7. A direct strategy to eliminate lead in gasoline reductions in pollutant emissions, in specificis to progressively ban the use of leaded gaso- cases. Air-quality claims for alternative fuels,line; several countries, including Thailand, however, must be carefully evaluated, becausehave adopted this strategy. in many cases similar or even greater emis-
8. Concerns have been raised regarding poten- sions reductions can be obtained with conven-tial valve seat recession in older vehicles with tional fuels and more advanced emissions con-"soft" valve seats if unleaded gasoline is used. trol systems. Which approach is the mostHowever, real-world evidence indicates that cost-effective depends on the conventional andthis is not a serious problem. alternative fuels' relative costs.
9. Tax policies that price unleaded fuel signifi-cantly below leaded fuel, as done in HongKong and Singapore, have also been found to RECOMMENDATIONSbe very effective in stimulating the sales ofunleaded fuel. 1. Encourage the use of lead-free gasoline and
10. While significantly reducing CO, the use of catalytic converters.oxygenates such as MTBE in cold tempera- 2.. Encourage tax policies that price unleadedture environments has raised concerns regard- gasoline lower than leaded fuel.ing adverse health effects in certain suscep- 3. Encourage gasoline reformulation by modi-tible individuals. Studies by USEPA and fying parameters such as volatility, oxygen-several U. S. states have failed thus far to iden- ates, sulfur levels, and hydrocarbon mix.tify a serious problem, although additional 4. Reduce the sulfur content of diesel fuels toresearch is ongoing. 0.05 percent by weight.
1 1. There is a clear worldwide trend toward lower 5. Promote an Inspection and Maintenance (I/levels of sulfur in diesel fuel. At a minimum, M) Program. Emissions reductions can occurthis reduces particulate emissions from diesel simultaneously with improvements in fuelvehicles. Recent European studies indicate that economy and reductions in vehicle mainte-for every 100 ppm reduction in sulfur, there nance costs. Reduced maintenance as a resultwill be a 0.16 percent reduction in particulate of using unleaded rather than leaded gasolinefrom light-duty vehicles and a 0.87 percent can save about Can$0.02 per liter.reduction from heavy-duty vehicles. Sulfur in 6. Encourage the use of alternative fuels includ-fuel also contributes to sulfur dioxide (SO2) ing methanol, ethanol, biodiesel, compressedin the atmosphere. natural gas, liquefied petroleum gas, electric-
12. Other diesel fuel properties such as volatil- ity, hydrogen, synthetic liquid fuels derivedity, aromatic content, and additives can also from hydrogenation of coal, and various fuelhave positive or negative effects on diesel blends, such as gasohol.
APPENDIX A: ADVERSE EFFECTS FROM
VEHICLE-RELATED POLLUTION
Cars, trucks, motorcycles, scooters, and buses pecially important because, "[O]f all the personsemit significant quantities of carbon monoxide in the community, the newbom child is the most(CO), hydrocarbons (HC), nitrogen oxides (NO.), prone to injury from overexposure to lead for sev-and fine particles (PM,,). Leaded gasoline, where eral reasons, and the damage that may be causedit is still used, is a significant source of lead in then will have the greatest long-term social andurban air. As a result of these emissions, many economic consequences." 4Another study whichmajor cities around the world are severely pol- monitored 249 children from birth to two years ofluted. This section will review some of the health age found that those with prenatal umbilical cordimpactsof these pollutants. blood lead levels at or above 10 micrograms per
deciliter consistently scored lower on standardintelligence tests than those at lower levels.5
LEAD A series of studies in the United Kingdomconfirmed these findings.6 Even after taking 15
During the last two decades, there has been an social factors into account, an IQ number deficitexplosion of knowledge about the adverse health of three was consistently found. While these sta-impacts of long-term exposure to low levels of tistics are not necessarily significant in any indi-ambient lead. 1 2 In response to this growing body vidual study (which is largely influenced by theof data, most industrialized countries, and sev- size of the sample, among other factors), the bodyeral developing countries, have introduced un- of data consistently shows such effects.leaded gasoline. Several countries have already Inaddition,Dr.Winneke(Germany)offeredfur-prohibited the use of leaded gasoline entirely. ther evidence that"neuropsychological effects are
Lead's toxic properties at high concentrations causally related to very low blood lead levels."'have been known since ancient times, as lead has Whiletheseeffectsmaynotbedominantinanypar-been mined and smelted for more than 40 centu- ticularinstance,theyareveryrealandpreventable.ries. Although precaution regarding lead's use has Several comprehensive studies regarding thebeen widespread for centuries, only recently has health impacts of lead have been conducted andlead's adverse impacts at very low levels been fully the major conclusions are summarized below.appreciated. Some of the most innovative workin this area was the 1979 report by Dr. Herbert The US National Academy of Sciences (1980)Needleman which showed that children with highlevels of lead accumulated in baby teeth experi- The U.S. National Academy of Sciences (NAS)enced more behavioral problems, lower lQs and study "Lead in The Human Environment" re-decreased ability to concentrate.3 More recent evi- ported, "[T]he evidence is convincing that expo-dence indicates that it is not only the length and sures to levels of lead commonly encountered inseverity of lead exposure that affects health dam- urban environments constitute a significant haz-age, but at what age exposure begins. This is es- ard of detrimental biological effects in children,
57
CEA.v FUEIs FOR ASIA: TECHNCAL OpDoNs FOR MoVING TowARDs UNLEADED GASOLINE AND Low-SUVEUR DIEML 58
especially those less than three years old. Some els. In its opinion, the Court stated that, "[T]heresmall fraction of this population experiences par- is compelling evidence that gasoline lead is a ma-ticularly intense exposures and is at severe risk." jor cause of lead poisoning in young children."Following that report, NAS recommended, "[A] In making this assessment, the Court found,serious effort should be made to reduce the "[R]ecent studies suggest that the recognizedbaseline level of exposure to lead for the general danger point of 30 micrograms per deciliter ispopulation of the United States."8 too high and that lead reduces intelligence at
blood lead levels as low as 10-15 microgramsThe U.S. Environmental Protection Agency per deciliter... [O]ther studies have correlated
blood lead levels of 10-15 micrograms per deci-The U.S. Environmental Protection Agency liter with altered brain activity." The Court con-(USEPA) summarized its results as follows: "The cluded that, "[T]he demonstrated connection be-majority of the comments emphatically rejected tween gasoline lead and blood lead, thethe proposition that lead was no longer a public demonstrated health effects of blood lead levelshealth problem. Sixty-four comments were re- of 30 micrograms per deciliter or above, and theceivedfromtheprofessionalhealthcommunityand significant risk of adverse health effects fromacademia. Sixtyoftheseopposedanylooseningof blood lead levels as low as 10-15 microgramsthe lead standard, and many suggested thattighter per deciliter, would justify USEPA in banningcontrolswouldbedesirable.Thirty-twocomments lead from gasoline entirely.""were received from local and state governments.All ofthesesupportedretentionofthecurrentstan- United Kingdom, The Royal Commission ondard to protect the citizen's health. Most of the Environmental Pollution (1983)commenters pointed to previous studies, as well astheirownexperiences,todemonstratethatleadhas In 1983, the Royal Commission reported thatan adverse effect on people at very low dosages, "[T]he safety margin between the blood lead con-and thatthe more the problem is studied the lower centrations in the general population and thosethe acceptable level of lead becomes. They con- at which adverse effects have been proven is toocludedthatprotectionofpublic health and welfare small.. .it would be prudent to take steps to in-demandsthatallreasonablestepsbetakentoelimi- crease the safety margin of the population as anate lead from the environment"9 In October 1982, whole." It continued that, "[M]easures should beUSEPA decided as aresultofthis reviewto reduce taken to reduce the anthropogenic dispersal ofthe amount of lead in gasoline even further. lead wherever possible... "12
Based on the growing body of data showing Most recently, British researchers reviewedthe adverse effects of lead, in 1985 USEPA re- every epidemiological study on lead and IQ pub-duced the maximum allowable lead content in lished since 1979 that examined over 100 chil-leaded gasoline to 0.1 grams per gallon. As part dren, and measured IQ as a function of blood orof that rulemaking, USEPA uncovered evidence tooth lead levels. Based on a meta-analysis of alllinking lead in the blood to high blood pressure. ' the data, they concluded that a doubling of body
lead burden from 10 to 20 micrograms per deci-The U.S. Court of Appeals (1983) liter in blood levels was associated with a mean
fall of about 1-2 IQ points."3
The U. S. Court of Appeals completed its review In summary, the available evidence indicatesof USEPA's decision to lower gasoline lead lev- that "[T]here is no known physiological function
59 APPENDixA
served by lead in mammalian rnetabolism. As far Because hemoglobin's affinity for CO is 200as cells are concerned, each molecule of lead has times greater than for oxygen, CO hinders oxygenthe potential to disrupt the chemical basis of transport from blood into tissues. Therefore, morenormal cellular function. For nerve cells, this blood mustbe pumped to deliver the same amountinterference is particularly destructive because of oxygen. Numerous studies in humans andcommunications between cells in the brain animals have demonstrated that individuals withdepends upon precisely controlled movements of weak hearts are placed under additional strain bysuch molecules such as calcium, sodium, the presence of excess CO in the blood. Inpotassium and chloride. Lead can interfere, on a particular, clinical health studies have shown amolecule by molecule basis, with these essential decrease in time to onset of angina pain in thoseelements."'4 individuals suffering from angina pectoris and
exposed to elevated levels of ambient CO.16
LEAD SCAVENGERSNITROGEN OXIDES
When lead additives were first discovered toimprove gasoline octane quality, they were also As a class of compounds, nitrogen oxides (NO.)found to cause many problems associated with are linked to a host of environmental concernsvehicles, especially significant deposits in the that negatively impact human health and welfare.combustion chamber and on spark plugs, causing Nitrogen dioxide (NO 2 ) has been linked withdurability problems. To relieve this, lead increased susceptibility to respiratory infection,scavengers were added with lead to gasoline to increased airway resistance in asthmatics, andencourage greater volatility in lead combustion decreased pulmonary function."' 18 It has beenby-products so they would be exhausted from the shown that even short-term NO2 exposure resultsvehicle. These scavengers are used today in in a wide range of respiratory problems in schoolleaded gasoline. Ultimately, such additives are children-coughs, runny noses, and sore throatslargely emitted from vehicles. This is important are among the most common."9 A French studybecause these lead scavengers, most notably by Dr. Orehek has shown that asthmatics areethylene dibromide, have been found to be especially sensitive to even one-hour exposures.2 0
carcinogenic in animals, and have been identified A small group of asthmatics were initiallyas potential human carcinogens by the National exposed to carbachol, a broncho-constrictorCancer Institute."5 Their removal, along with the representative of urban pollen, and then to NO ;2'removal of lead, should result in significant health some participants experienced adverse effects,benefits. such as increased airway resistance, at levels as
low as 0.1 parts per million for 1 hour.NOx also participates in the formation of the
CARBON MONOXIDE family of compounds known as photochemicaloxidants, and in acid deposition. Finally, as a
Carbon monoxide (CO)-an odorless, invisible result of secondary transformations in thegas, created when fuels containing carbon are atmosphere, NO emissions are converted toburned incompletely-poses a serious threat to nitrates, thereby increasing the accumulation ofhuman health. Persons afflicted with heart disease particulates in the air.2'and carrying fetuses are especially at risk.
CL.N Fums FoR As: TECHNICAL OPONS FOR A'oyING TowARDs UNk-ADEgD GASOL!NE AND LOW-SuLFUR DIESEL 60
PHOTOCHEMICAL OXIDANTS accidental death rates tend to rise and fall in nearlockstep with daily PM levels-but not with other
The most widespread air pollution problem in pollutants.2 5 Because the correlation held up attemperate climates is ozone, a photochemical even very low levels-in one city at just 23 per-oxidant resulting from the reaction of NOX and cent of the federal PM limit-these analyses sug-hydrocarbons in the presence of sunlight. Motor gested to the researchers that as many as 60,000vehicles are a major source of both of these pre- U.S. residents per year may die from breathingcursor pollutants. Ozone causes eye irritation, particulates at or below legally allowed levels.26
coughing, chest discomfort, headache, upper res- More recently, another study has emergedpiratory illness, increased asthma attacks, and re- showing a strong link between particulate airduced pulmonary function.2 2 pollution and mortality.2 7 The study is distinc-
USEPA has recently proposed to lower the tive in that it used a prospective cohort designcurrent ozone air quality standard from 0.12 parts that allowed for direct control of other individualper million (ppm) to 0.08 ppm.23 Furthermore, at- risk factors such as cigarette smoking or diet. Intainment of the standard would no longerbe based addition, the study was larger and represented aupon I-hour averages, but instead on 8-hour aver- greater geographic area than any previous study.ages. The proposed revised standard would pro- Air pollution data from 151 U.S. metropoli-vide protection for children and other populations tan areas were linked with individual risk factorsvulnerable to a wide range of ozone-induced in552,138 adultswhoresidedintheseareaswhenhealth effects, including decreased lung function were enrolled in this 1982 study. Deaths were(primarily in children active outdoors), increased ascertained through 1989. Sulfates and fine par-respiratory symptoms (particularly in highly sen- ticulate air pollution were associated with a dif-sitive individuals), hospital admissions and emer- ference of approximately 15-17 percent betweengency room visits for respiratory causes (among mortality risks in the most polluted cities, and inchildren and adults with pre-existing respiratory the least polluted cities. Even in cities meetingdiseases such as asthma), and inflammation and U. S. Federal Clean Air standards, the risk of deathpossible long-term damage of the lungs. is 2-8 percent higher than in the cleanest cities.
Ithas alsobeendemonstratedinnumerous stud- Certain particles appear to be especially haz-iesthatphotochemical pollutants seriously impair ardous. For example, diesel particles, because ofcertain crops' growth. For example, the Congres- their chemical composition and extremely smallsional Research Service (U.S. Library of Congress) size, have raised special health and environmentalfound that "[T]he short-run or immediate impacts concerns. Diesel PM consists mostly ofthree com-of ozone are evident in annual crop yield de- ponents: soot formed during combustion, heavycreases estimated at US$1.9 to US$4.3 billion."2 4 hydrocarbons condensed or adsorbed on the soot,
and sulfates. In older diesels, soot was typically40-80 percent of the total PM. Newer in-cylinder
PARTICULATES emissions controls have reduced the soot contri-butionto particulate emissions from modem emis-
A series of studies released in the last few years sions-controlled engines considerably. However,indicate that particulates (PM) may be the most much of the remaining particulate mass consistsserious urban air pollution problem. By correlat- of heavy hydrocarbons adsorbed or condenseding daily weather, air pollutants, and mortality in on the soot. This is referred to as the soluble or-six U. S. cities, scientists have discovered that non- ganic fraction (SOF) of the particulate matter.
61 APPENDIXXA
The SOF is derived from Ilbricating oil, un- To put the concerns with diesel NOX and PMburned fuel, and compounds formed during com- into perspective, one recent study attempted tobustion. The relative importance of each of these quantify thehealth benefits associatedwith reduc-sources varies from engine to engine. ing diesel PM and NOX.3' Based on a careful re-
The International Agency For Research on view of the available health information, the au-Cancer conducted a comprehensive assessment thors concluded that reducing one gram per mileof available health information on diesel PM in of PM or NOX over a 100,000-mile vehicle life-June 1988, and concluded that diesel PM is prob- time would produce benefits of US$11,432 andably carcinogenic to humans.2 8 US$1,175, respectively. Focusing specifically on
Other studies conducted at the Fraunhofer In- Los Angeles' 1992 heavy-duty vehicle fleet, thestitute in Germany have suggested that the diesel authors conclude that a 50 percent reduction inparticle itself, stripped of organic and other sur- NOX and PMIO emissions would be worthface materials, may also be carcinogenic. Studies US$9,200 and US$13,500 per vehicle. A 90 per-under the auspices of the Health Effects Institute cent reduction would have a value of US$16,600(}EI), ajointly funded industry-government pro- and US$24,300 per vehicle respectively. It isgram, recently verified this conclusion. An HEI important to emphasize that these amounts re-study reported that, "[R]esults, and recent find- flect only the health benefits. Studies indicate thatings from other laboratories, suggest that (1) the the economic benefits of reduced soiling andsmall respirable soot particles in diesel exhaust improved visibility are also significant.are primarily responsible for lung cancer devel-oping in rats exposed to high concentrations ofdiesel emissions, and (2) at high particle concen- PHysIcs AND CHEMISTRYtrations, the mutagenic compounds adsorbed onto OF PARTICULATE MATTER
the soot play a lesser role, if any, in tumor devel-opment in this species."29 This is quite signifi- Atmospheric particles originate from a variety ofcant, as it indicates that it is important to control sources and possess a range of morphological,the particles themselves, not just the organic chemical, physical, and thermodynamic proper-material sitting on the surface of the carbon. ties. Examples include combustion-generated par-
In a subsequent analysis, HEI raised questions ticles such as diesel soot or fly ash, photochemi-about this conclusion. The authors argue that be- cally produced particles such as those found incause the rats were exposed to very high concen- urban haze, salt particles formed from sea spray,trations over their full lifetimes, the observed and soil-like particles from resuspended dust. Par-effects are more likely the result of the impair- ticles are liquid or solid; others contain a solidment of the rat's ability to clear particles from its core surrounded by liquid. Atmospheric particleslungs, leading to inflammation and rapid cell pro- contain inorganic ions and elements, elementalliferation. The researchers noted that similar ef- carbon, organic compounds, and crustal com-fects did not occur in hamsters, and results with pounds. Some atmospheric particles are hygro-mice were mixed.30 scopic and contain particle-bound water. The
While further studies are carried out to deter- organic fraction is especially complex. Hundredsmine which diesel particle elements are most of organic compounds have been identified inhazardous, the prudent course of action would atmospheric aerosols, including alkanes, alkanoicseem to be to reduce both the organics and the and carboxylic acids, polycyclic aromatic hydro-particulate mass. carbons, and nitrated organic compounds. 32
CLEAN F,vs FOR AsA: TECHNICAL 0P2oNS FOR MOVIN3G TowARDs UNLEADED GASOLaNE AND Low-SULFUR DIEsEL 62
Particle diameters span more than four orders VOCs). Fugitive dust is a primary pollutant. Ma-of magnitude-from a few nanometers to one jor sources of particle emissions are classified ashundred micrometers. Combustion-generated par- major point sources, mobile sources, and areaticles, such as those from power generation, auto- sources; these are anthropogenic. Natural sourcesmobiles, and tobacco smoke, can be as small as also contribute to ambient concentrations.0.01 micrometers or as large as 1 micrometer. At- Fugitive dust is a major PM,, contributor atmospheric particles produced by photochemical nearly all sampling sites, although the averageprocesses range in diameter from 0.05 fugitive dust source contribution is highly vari-micrometers to 2 micrometers. Fly ash produced able between sampling sites in the same areas,by coal combustionrangesfrom O.l micrometersto and is also highly variable between seasons.50 micrometers or more. Wind-blown dust, Primary motor vehicle exhaust in the Unitedpollens, plant fragrnents, and cement dust are gen- States represents as much as 40 percent of aver-erally above 2 micrometers in diameter. age PM,, at many sampling sites. Vegetation
Recent measurements of the size distributions burning outdoors and residential wood burningof primary particles confirm USEPA conclusions are significant sources in residential areas. Fugi-that most fugitive dust emissions are particles tive dust from paved and unpaved roads, agri-larger than 2.5 micrometers, and that most emis- cultural operations, construction, and soil erosionsions from combustion sources are in sizes smaller constitute about 90 percent of nationwide primarythan 2.5 micrometers. As illustrated in figure A. 1, emissions in most countries. Fugitive dust con-diesel truck emissions are almost all less than 1.0 sists of geological material that is suspended intomicrometer in size; par-ticles in this size rangeare especially hazard- Figure A. 1: Size Distribution of Typical Particlesous when inhaled asthey are able to pen-etratetothedeepestpart 140% l above 10 micronsof the lung, where the .b10 microncritical gas exchange 120% - 2<10 microntakes place. / i / 711 micron
100% __,_________micron
SOURCES OF 80%SUSPENDEDPARTICLES 60% -
The ambient atmo- 40% -sphere contains bothprimary and secondary 20% -particles; the formerare emitted directly by 0% Die Fugitive Dustsources, and the latterare formed from gases Source: U.S. Environmental Protection Agency, April 1995. "PM Criteria Docu-
(SO 2 , NOx, NH3, ment" (Draft).
63 APPENDIX A
the atmosphere by natural wind and anthropo- CONCLUSIONS REGARDING
genic activities from sources such as paved and ADVERSE HEALTH EFECTS
unpaved roads, construction and demolition ofbuildings and roads, storage piles, wind erosion, Vehicle emissions of CO, HC, NO,, and fine PM re-and agricultural tilling. sultinavariety of adverse effects on health and the
Mobile sources are major emitters of primary environment Focusing solely on the health con-particles, NOX, and VOCs. They are also minor sequences of these pollutants, the World Healthemitters of SO2 and ammonia. On-road gasoline- Organization (WHO) recently published revisedand diesel-fueled motor vehicle engines are the air quality guidelines for Europe, which are sum-primary source of mobile source emissions in marized in table A. 1.most countries, and consequently, emissions es-timation methods are most highly developed forthese vehicles. Motor vehicle exhaust contains ENDNOTES
high concentrations of organic and elementalcarbon, but their ratios are very different from 1. Needleman, H. March/April 1980. "Leadthose found in wood combustion, elemental car- Exposure And Human Health: Recent Data Onbon being nearly equal to the organic carbon An Ancient Problem," Technology Review.abundance. 2. Office of Research and Development, U.S.
Environmental Protection Agency. December1977. "Air Quality Criteria For Lead."
OTHER ToxIcs 3. Needleman, H. et al. March 29, 1979. "Defi-cits In Psychological And Classroom Perfor-
The 1990 CleanAirAct directed USEPAto com- mance Of Children With Elevated Dentineplete a study of toxic air emissions associated Lead Levels," The New England Journal Ofwith motor vehicles and motor vehicle fuels. The Medicine. 300(13).study found that the aggregate risk in the United 4. Moore. January 24, 1980. "Exposure to LeadStates is 720 cancer cases. Gasoline and diesel In Childhood: The Persisting Effects," Nature.PM, which are considered to represent motor ve- 283(24).hicle polycyclic organic matter (POM), are 5. Yule, Lansdown, Millar and Urbanowicz.roughly equal contributors to the risk. The com- 1981. "The Relationship Between Blood Leadbined risk from gasoline and diesel PM was Concentrations, Intelligence and Attainment16-28 percent of the total, depending on the year in a School Population: a Pilot Study," Devel.,examined. Benzene is responsible for roughly 10 Med Child. Neurology, (23):567-576.percent of the total for all years. The aldehydes, 6. Needleman, 1989.predominately formaldehyde, were responsible 7. Comments at Conference, Lead In Petrol,for roughly 4 percent of the total for all years. Winneke, May 1983
A variety of studies have found that in metro- 8. U.S. National Academy of Sciences. 1980.politan areas mobile sources are possibly the most "Lead In The Human Environment". Wash-important air pollution source category, in terms ington, D.C.of contributions to health risks. For example, ac- 9. August 27, 1982. Federal Register. 47(167).cording to USEPA, mobile sources are respon- 10. Schwartz, J., H. Pitcher, R. Levin, B. Ostro,sible for almost 60 percent of air pollution-re- and A.L. Nichols. 1985. Costs andBenefits oflated cancer cases in the United States per year. Reducing Lead in Gasoline: Final Regulatory
CLEAN FUELs FOR ASIA: TECHNICAL OPTtONS FOR MOVING TowARDs UNLEADED GASoUNE AND Low-SULFUvR DIESEL 64
Impact Analysis,Report No. Table A.]: Summary of WHO-Recommended GuidelinesEPA-230-05-85--006, U. S. EPA, Compound Guideline Value Averaging Time
Washington, D.C. Ozone* 120 g/m3 (0.06 ppm) 8 hours
11. United States Courtof Appeals, No. 82- Nitrogen Dioxide 200 g/m3 (0.11 ppm) 1 hour
2282, Small Refiner Nitrogen Dioxide 40-50 g/m3 (0.021-0.026 ppm) Annual
Lead Phase-Down Carbon Monoxide 100 mg/m3 15 minutes
Task Force, et al. v.U.S. EPA, April 22, Carbon Monoxide 60 mg/m3 30 minutes1983. Carbon Monoxide 30 mg/m3 1 hour
12. Royal Commission Carbon Monoxide 10 mg/m3 8 hourson Environmental ParticulateMatter*
Pollution (U.K.)April 1983. "Lead In * Resulting from the photochemical reaction between hydrocarbons and nitrogen oxides.
The Environment," I No guideline values were set for particulate matter because there is no evident threshold for
Ninth Report. effects on morbidity and mortality.
13. Pocock S.J., et al, Source: WHO Regional Office for Europe, 1995. "Update and Revision of the Air
"EnvironmentalLead Quality Guidelines for Europe."
and Children's Intel-ligence: A System-aticReviewoftheEpidemiologicalEvidence", 20. Orehek, et al. February 1976. "Effect of Short-BMJ 1994, November 5; 309:1189-97. Term, Low-Level Nitrogen Dioxide Exposure
14. Silbergeld, Dr. Ellen. Autumn 1982. "Lead onBronchialSensitivityofAsthmaticPatients,"Poisoning," Toxic Substance ControlNewsletter. The JournalofClinicalInvestigations, Vol. 57.
15. Sigsby et al. "Automotive Emissions of Eth- 21. Atmospheric nitrate is essentially secondary,ylene Dibromide," Society of Automotive formed from reactions involving oxides ofEngineers, #820786. nitrogen to form nitric acid.
16. U.S. Environmental Protection Agency. 22. U.S. Environmental Protection Agency. AprilMarch 1990. "Air Quality Criteria For Car- 1978. "Air Quality Criteria For Ozone Andbon Monoxide" (External Review Draft). Other Photochemical Oxidants."
17. U. S. Environmental Protection Agency. June 23. December 1996. Federal Register.1980. "Air Quality Criteria For Nitrogen Ox- 24. Congressional Research Service, Library ofides" (Draft). Congress. May 1982. "Air Pollution Impacts
18. Ferris. May 1978. "Health Effects of Expo- On Agriculture And Forestry."sure To Low Levels of Regulated Air Pollut- 25. Dockery et al. December 9, 1993. "An Asso-ants, A Critical Review," Journal of The Air ciation Between Air Pollution And MortalityPollution Control Association. In Six U.S. Cities," The New England Jour-
19. Mostardi etal. September/October 1981. "The nal of Medicine.University Of Akron Study on Air Pollution 26. Schwartz, Dr. Joel. May 1991. "Air Pollu-and Human Health Effects," Archives of En- tion and Daily Mortality in Philadelphia," pre-vironmental Health. sented at the 1991 meeting of the American
65 APPENDixA
Lung Association, Anaheim, CA. Effects Institute Research Report No. 68.27. Pope at al. 1995. 30. The Health Effects Institute. 1995.28. International Agency For Research on Can- 31. Small, A. and C. Kazimi, Department of Eco-
cer uses the term "carcinogen" to denote an nomics, University of California-Irvine. Janu-agent that is capable of increasing the inci- ary 1995. "On The Costs of Air Pollution Fromdence of malignant tumors. Motor Vehicles," The Journal of Transport
29. Mauderly et al. October 1994. "Pulmonary Economics.Toxicity of Inhaled Diesel Exhaust and Car- 32. U.S. Environmental Protection Agency. Aprilbon Black in Chronically Exposed Rats," Health 1995. PM Criteria Document (Draft). April 199 5.
APPENDIX B: CONTROLS ON GASOLINE-
FUELED VEHICLES
Over the last decade, great progress has been gies involve the physics of combustion, changesachieved in the development of control technolo- in engine design, and exhaust treatment devices.gies that have dramatically reduced gasoline-fu-eled vehicle emissions, and the many adversehealth and environmental effects of these emis- COMBUSTION AND EMISSIONSsions. However, to maximize these benefits andutilize the best available technology-the emis- Hydrocarbon (HC) emissions include thousandssions catalyst-it is necessary to fuel catalyst- of chemical compounds, generally resulting fromequipped vehicles exclusively with unleaded incomplete fuel combustion. The amounts emit-gasoline, since lead poisons converter systems. ted are related to the air/fuel mixture inducted,The following section reviews the technologies peak temperatures and pressures in each cylin-available to reduce gasoline vehicle emissions, der (whether lead is added to the gasoline or not),and the important role that catalysts play in a and hard-to-define factors including combustionsuccessful long-term clean fuel strategy. chamber geometry.
Before emissions controls were mandated, en-gine crankcase fumes were vented directly into Nitrogen oxides (NO) are generally formedthe atmosphere. Crankcase emissions controls in- during conditions of high temperature and pres-volved closing the crankcase vent port, and were sure, and excess air (to supply oxygen). Peak tem-introduced in new automobiles in the early 1 960s. peratures and pressures are affected by a numberControlling these emissions is no longer consid- of engine design and operating variables as wellered a significant technical issue. as the concentrations of NOX in the exhaust.
Evaporative hydrocarbon (HC) emissions re-sult from fuel evaporation in the carburetor float Carbon monoxide (CO) results from incompletebowl and fuel evaporation in the gas tank. Con- combustion of carbon contained in the fuel. Itstrolling these emissions generally requires feed- concentration is generally governed by complexing the HC vapors back into the engine to be stoichiometry and equilibrium considerations.burned with the rest of the fuel. When the engine The only major engine design or operating vari-is not operating, vapors are stored either in the able that seems to affect its concentration is theengine crankcase, or in charcoal canisters which air/fuel mixture: the leaner the mixture or theabsorb these emissions to be burned off when more air per unit of fuel, the lower the CO emis-the engine is started. sions rate.
The most difficult emissions control problemis that of vehicle exhaust emissions. Fortunately, Lead compounds (and their associated scaven-progress has been made during the last decade in gers) are emitted by an automobile almost directlydeveloping control technologies that can dramati- in proportion to the amount of fuel used by acally reduce exhaust pollutants. These technolo- vehicle, and the concentration of lead in the fuel.
67
CLEANFUEs FORAsIA: TEHNImcAL OPuONSFOR4MOuNG TowARDs UA7s4DED GASOLuNE AN Low-SuLPuR DIESL 68
ENGINE DESIGN PARAMETERS dation of unburned hydrocarbons is greater, andoverall hydrocarbon emissions are reduced.
Certain engine design parameters can induce sig-nificant changes in emissions. Most notable Compression Ratio and Combustionamong these are the air/fuel ratio and mixture Chamberspreparation, ignition timing, and combustionchamber design and compression ratio. According to the fundamental laws of thermody-
namics, increases in compression ratio lead to im-Air/Fuel Ratio and Mixture Preparation proved thermal efficiency, and concurrently, in-
creased specific power and reduced specific fuelThe air/fuel ratio has a significant effect on all consumption. In actual applications, increases inthree major pollutants (CO, HC, and NO) from compression ratios tend to be limited by avail-gasoline engines. In fact, engine-out CO emis- able fuel octane quality. Over time, a balance issions are almost totally dependent on the air/fuel struck between increased fuel octane valuesratio, while HC and NOx emissions rates are (through refining modifications and fuel modifi-strongly influenced, depending on other engine cations, such as the addition of tetraethyl lead todesign parameters. CO emissions can be dramati- gasoline), and higher vehicle compression ratios.cally reduced by increasing the air/fuel ratio to Compression ratios can be linked to combus-the lean side of stoichiometric. HC emissions can tion chamber shapes, and in certain combinationsalso be reduced significantly by increasing the these parameters can have a significant impact onair/fuel ratio until flame speed becomes so slow emissions. Highersurfaceto volumeratioswill in-that pockets of unburned fuel are exhausted be- creasetheavailablequenchzoneandleadtohigherfore full combustion occurs or, in extreme cases, HC emissions; conversely, more compact shapes,if misfire occurs. Conversely, NO, emissions in- such as hemispherical or bent roof chambers, re-crease as air/fuel mixtures are enleaned up to the duceheatloss andincreasemaximumtemperatures.point of maximum or peak thermal efficiency. This tends to increase the formation of NOX whileBeyond this point, further enleanment can result reducing HC. Furthermore, combustion chamberin lower NOx emissions rates. material, and size and spark plug location can in-
fluence emissions. In general, because of its higherIgnition Timing thermal conductivity, aluminum engine heads lead
to lower combustion temperatures, and thereforeIgnition timing is the second most important en- lower NO rates, although at the expense of in-gine control variable affecting "engine-out" HC creasedHCemissions. Sincethelengthoftheflameand NOx from modem engines. When timing is path has a strong influence on engine detonationoptimized for fuel economy and performance, HC and fuel octane requirement, larger combustionand NOx emissions are also relatively high (ac- chambers that can lower HC emissions tend to betual values depending, of course, on other en- used only with lower compression ratios.gine design variables). As ignition timing is de-layed (retarded), peak combustion temperaturestend to be reduced, thereby lowering NOx and EMISSIONS CONTROL TECHNOLOGIESpeak thermal efficiency. By allowing combus-tion to continue after the exhaust port is opened Tighter emissions standards have required that(resulting in higher exhaust temperatures), oxi- more specific attention be given to the treatment
69 APPENDixB
of vehicle exhaust emissions. Commonly used nition systems can increase dilution tolerance. Thetechnologies to control exhaust emissions include latest technique for improving dilution tolerancerecirculation of exhaust gases, electronic control is to increase the air-fuel charge's burn rate orof engine performance, exhaust after-treatment flame speed. Dilution can then be increased untildevices, and advanced combustion techniques. the burn rate again becomes limiting. Several
State-of-the-art engine modification alone can- techniques have been used to increase burn ratenot reduce emissions to the same extent as can a including increased "swirl" and "squish," shorterthree-way catalyst. Compared to a carburetted en- flame paths, and multiple ignition sources.gine, an electronically controlled engine equippedwith a 3-way catalyst can reduce CO emissions Electronicsfrom a mean rate of 7.5 grams per kilometer to 1.5gramsperkilometer,HC emissions from 1.5 grams With so many interrelated engine design andper kilometer to 0.25 grams per kilometer; and operating variables playing an increasingly im-NO from 2.0 grams per kilometer to 0.25 grams portant role in the modern engine, the controlper kilometer. Electronic fuel injection and igni- system has become increasingly important. Sparktion systems (EFI) without a catalytic converter timing modifications must be closely coordinatedare effective in reducing CO and HC emissions with air/fuel ratio changes and amount of EGR,but have only a minor impact on NOX emissions.' lest significant fuel economy or performance
penalties result from emissions reductions, orExhaust Gas Recirculation NO emissions increase as CO decreases. In ad-
xdition, controls that can be more selective de-
Recirculating a portion of the exhaust gas back pending on engine load or speed have been foundinto the incoming air/fuel mixture is frequently beneficial in preventing adverse impacts.used as a technique to lower NOx. The dilution To meet these requirements, electronics haveof the incoming charge reduces peak cycle tem- begun to replace more traditional mechanicalperature by slowing flame speed and absorbing controls. The conventional combination of car-some combustion heat. buretor and distributed ignition systems can now
Charge dilution of homogeneous-charge en- be replaced by electronic fuel injection (EFI) andgines by excess air and/or by exhaust gas recircu- ignition to provide more precise control.2 Fur-lation (EGR) has been used for many years. The ther, electronic ignition timing control has beenuse of excess air alone results in relatively small shown to optimize timing under all engine con-NOxreductionsofabout35-40percent WhenEGR ditions, and has the added advantage of reducedis incorporated, substantially higher NO. reduc- maintenance and improved durability, comparedtions have been demonstrated However, exces- to mechanical systems. When both ignition tim-sive dilution can result in increased HC emissions, ing and EGR are electronically controlled, NOxdriveability problems, or fuel economy losses. emissions can be reduced with no fuel economy
Fuel consumption can be modified when EGR penalty, and in some cases, with an improvement.is utilized. Brake-specific fuel consumption andexhaust temperature decrease with increasing Exhaust After-Treatment DevicesEGR, because dilution with EGR decreases pump-ing work and heat transfer, and increases the ratio Emissions catalysts and thermal reactors, generi-ofspecific heats oftheburned gases. Improvements cally known as exhaust after-treatment devices,in mixture preparation, induction systems, and ig- were developed in order to achieve a quantum re-
CLEAN Fis FOR ASI: TECHIcAL OPzroNs FOR MOAING TowARDs U.EADH GASOINE AND Low-SLFUR DIESEL 70
duction in exhaust emissions beyond those attain- tion catalyst systems. As a result, three-way sys-able through engine design modifications. The tems have indirectly fostered improved air/fuelcatalyst comprises a ceramic support, a washcoat management systems such as advanced carbure-(usually aluminum oxide) to provide a very large tors, throttle body fuel injection, and electronicsurface area, and a surface layer of precious met- controls. Three-way catalyst systems are alsoals (platinum, rhodium, and palladium are the most sensitive to the use of leaded gasoline. Even ancommonly used) to perform the catalytic func- occasional tank of leaded gasoline will have ation. The catalyst is housed in a metal container small but permanent effect on the level of emit-forming part of the vehicle exhaust system. For ted pollutants.effective operation, the catalyst temperature must Thermal reactors are well-insulated vesselsexceed the light-off value (about 3000 °C), which with internal baffling to allow several passes oftakes 1-3 minutes in typical urban driving con- the exhaust gas to maintain high temperatures andditions.3 The cost of a catalytic converter and its extend the residence time, and therefore promoteaccompanying equipment is about US$250-750 oxidation of CO and HC emitted from the en-per automobile (1981 prices), equivalent to a gine. To maintain high temperatures, they are4-20 percent increase in vehicle cost.4 Over the often used in conjunction with exhaust port lin-life of a vehicle, these devices can reduce HC ers, which reduce heat losses. In spite of this, aemissions by an average of 87 percent, CO by 85 major problem with these systems is the diffi-percent, and NO. by 62 percent.5 culty in maintaining exhaust temperatures high
An oxidation catalyst is a device placed on the enough to promote combustion. Measures to in-tailpipe of a car. If the chemistry and thermody- crease exhaust temperatures such as retarded ig-namics are properly maintained, the device will nition, richer air/fuel ratios, or valve timing de-oxidize almost all the HC and CO in the exhaust lays result in increased fuel consumption.stream to carbon dioxide and water vapor. Start- Because of these problems, thermal reactors haveing in 1975, oxidation catalysts have been placed gradually disappeared.in more than 80 percent of all new cars sold inthe United States. In 1981, they have been placed Lean-Burnon 100 percent of new cars. A major impedimentto the use of catalysts is lead in gasoline. Cata- At one point, it was believed that combustionlyst systems are destroyed by the lead in vehicle advances, especially lean-burn, might ultimatelyexhaust. A unique advantage of catalysts is their allow the catalyst to be eliminated. Recent expe-ability to selectively eliminate some of the more rience, however, indicates that low HC and NOharmful compounds in vehicle exhaust such as levels are not attainable across the range of nor-aldehydes, reactive hydrocarbons, and poly- mal driving conditions through the use of ad-nuclear hydrocarbons. vanced combustion technology alone. At least an
Three-way catalysts are able to lower HC, CO oxidation catalyst is needed to control HC emis-and NOx levels simultaneously. Volvo first in- sions. Also, under higher speeds and higher loadtroduced them in the United States in 1977. They driving modes, such as those reflected in the re-became widely used when the U.S. NOX stan- cently established European extra urban drivingdard became more stringent (1.0 grams per mile) cycle, supplemental NOX control may also bein 1981. For three-way catalysts to work effec- needed. Recent European studies of high-speedtively, it is necessary to control air/fuel mixtures driving conditions demonstrate that three-waymuch more precisely than is needed for oxida- catalysts are necessary to minimize NOX emis-
71 APPEADIX B
sions. In addition, concerns regarding toxic pol- of unleaded gasoline and cleaner engine oils, re-lution are increasing, and lean-burn engines do sulting in overall reductions in lead pollution.not appear to be as effective as conventional Further, to optimize the effectiveness of thesecatalyst-equipped engines in lowering poly- systems, better air/fuel and spark managementnuclear organics and other noxious compounds systems have evolved, generating a much greaterfrom motorvehicle exhausts, unless they are also use of both electronics and fuel injection. In turn,equipped with catalytic converters. these advances increase the prospects of better
fuel efficiency and lower CO2 emissions.
EMIssIoNs CONTROL AND ENERGY
CONSERVATION COST OF EXHAUST EMIssIONS CONTROLS
Today there are many technologies to improve Implementing tighter emissions standards hasfuel economy and reduce significant exhaust three cost implications:emissions, such as advanced air/fuel management * Increased vehicle costs, including additionalsystems including fuel injection, spark timing or more advanced components;electronic controls, advanced choke systems, and * Increased or reduced vehicle maintenanceimproved transmissions. In fact, some advances costs; andwere made as a direct result of increasingly tighteremissions control requirements. Furthermore, inthe absence of tightening emissions requirementsthese advanced technologies almost certainlywould nothave been placed in automobiles. Oncethe technologies were introduced, fuel economyoften improved faster than when emissions re- BoxB. : US. Frel Efficiency Underquirements were less stringent. Emissions Standards (-1987)
Lead is added to gasoline because it is an in-Leadenise wad to gasoline bcause tluis anr in- In the United States, improved emissions standardsexpensive way to increase octane values for im- have coincided with improvements in fuel economy.
proved vehicle fuel efficiency. In fact, a halt to A sales-weighted fleet average of 14.9 miles per
adding lead in gasoline entails a small (less than gallon in 1967 increased to 27.3 miles per gallon in1 percent in the United States) fuel penalty at the 1987-an increase of 83 percent. Correcting forrefinery. However, the greatest potential impact, vehicle weight reductions, the improvements, com-
and the one that has generated the most serious pared with pre-controlled cars were about 47 per-cent. The introduction of unleaded fuel and cata-
debate, iS the impact on vehicle fuel efficiency- lytic converters in 1975 coincided with substantialdoes it improve or deteriorate? fuel economy gains. At a minimum, this demon-
In Europe, North America, and the Pacific strates that tight emissions standards are not an im-Rim, vehicle technology is being pushed harder pediment to fuel economy gains. Because someand harder to achieve low pollution levels, and technologies such as electronic controls, advanced
common elements are emerging. In every case spark management systems, or advanced air-fuelthe least-polluting vehicles are equipped with management systems are beneficial for both emis-
sions reductions and improved fuel efficiency, en-catalytic converters. As these systems are de- couraging use of these systems in response to tightstroyed by lead and by phosphorus in most en- emissions standards may actually have stimulatedgine oils, they inevitably foster the introduction some advances in fuel economy.
CLEAN FuELs FOR AswA. TECHNICAL OP27oNs FOR MOVING TowARDs UAEEADED GASO.LNE AMD LOW-SuLFUR DiEsFL 72
Greater or lesseramounts of fuel con- Table B.R: The Cost to Consumers of Various Emissions Controlsumed if emissions Technologies:control measures af-fect fuel consump- Technologies Price Increase Fuel ConsumpUontion one way or the (percenQ Increase (percent)other. Lean-bum engine with carburetor and 1.0 -2Estimated increases conventional ignition
in the cost of vehicles Pulsair and EGR 4.5 +3and changes in fuelacnsumptiongfor vain- Lean-bum engine with carburetor and 2.0 +1consumption for vari- programmed ignitionous low-emissions en-gines and exhaust treat- Recalibrated conventional engine with EFI 8.0 +2ment configurations Lean-bum engine and EFI 9.0 -7are given in table B. 1.6 Lean-bum engine oxidation catalyst 4.5 -3
In the United States,USEPA developed a Open loop 3-way catalyst carburetor 4.1 +2cost model to deter- Lean-bum engine-closed loop, EFI varable 15.0 -7mine estimates of the intake system-oxidation catalystinitial cost paid by con- Closed loop-EFI-3-way catalyst 13.0 +3sumers to comply with Baseline: small vehicle, 1.4 litre conventonal carburetor engine meeting ECE 15/04 standard.
U.S. emissions stan-dards. The cost esti- Source: Organizaton of Economic Cooperation and Development, 1998. "Transport and
Environment."mates were based on ananalysis of the retailprice equivalent ofeach component in the emissions control system Range Transboundary Air Pollution to discusscomponent used in gasoline-fueled vehicles. The methods for researching VOC emissions and con-list of emissions control components on each car trol strategies. As part of the development of awas obtained from the Application for Certifica- UN ECE protocol to control these emissions, ation submitted to USEPA by automobile manu- technical annex (dealing with mobile sources)facturers. Prices and price estimates were ob- was drafted in Switzerland on April 6, 1990. Thetained from three sources: (i) a study conducted major conclusion was that closed loop three-wayfor USEPA; (ii) a price survey of dealer parts catalyst technology is cleaner and more efficientdepartments; and (iii) direct request to the manu- than either engine modifications or lean-bum set-facturers for parts price information. Based on tings with open loop catalysts.the above sources, new automobile price in- Recognizing that there is no universalcreases resulting from tighter U. S. emissions stan- consensus regarding the cost and fuel economydards were estimated (table B.2). All emissions impacts of emissions regulations, it would stillstandards have been converted to the U.S. 1975 be fair to say that technology exists which cantest procedure (CV5-75) along with the U.S. com- lower emissions at a cost of approximately 3-5pliance program. percent of the overall cost of a vehicle with no
An international workgroup has been formed pollution controls, and with improved fuelunder the auspices of the Convention on Long economy (table B.3).
73 APPENDIX B
TECHNOLOGICALADVANCES ON THE iTable B.2: U.S. Automobile Emissions Standards (grams per
HORIZON mile) and Estimated Additional Cost (1968-96)7, 8
Vehicle emissions re- Model Year HCICOINOx (grams/mile) Initial cost increase (US$ 1981)duction technology is 1968-69 5.9/50.8/N.R. 30continually evolving.Future control elements 1970-71 3.9133.3/N.R. 50will include lower trace 1972 3.0/28.8/N.R. 70lead levels in unleaded 1973-74 3.0/28.0/3.1 100gasoline, more ad- 197576 1.5/15.0/3.1 150vanced emissions con-trol components, more 1977-79 1.5/15.012.0 175durable catalysts, better 1980 0.41/7.0/2.0 225airfuelmanagementsys- 1981 0.41/3.4/1.0 350tems, and electronics.California, still plagued 1990 (proposed 0.25/3.4/0.4 (by 1995/96) na.by severe smog condi- legislation) 0.125/3.4/0.2 (by 2003) n.a.tions in Los Angeles, N. R. = not required.continues itsworldwide ni. a. = not available.leadership in extendingpollution control re- Source:quirements. OECD [1988a]. Transport and Environment, Paris.
USEPA [1988]. Mobile Source Emission Standards Summary. Office of Air and Radiation,Technological i m - United States Environment Protection Agency, Washington, D.C.
provements for con-trolling HC and CO.The level of tailpipe Table B.3: Conclusion of UN ECE Protocol (1990)HC emissions frommodem vehicles is pri- Technology Option Emission Level* Cost* Fuel Consumption*marily a function of Uncontrolled 400 <100engine-out emissions, Engine Modifications 100 Base 100and the catalyst's over-all conversion effi- Lean Setting wiox. Cat 50 150-200 100ciency, both of which Closed Loop TWC 10 250-400 95are highly dependent Advanced Closed Loop 6 350-600 90the fuel and ignition Note: * Emissions are expressed as percent with engine modification option as 100.
systems functioning Source: European Conference of Ministers of Transport (1990).
properly. A fairly com-prehensive systemwhich tackles this problem has evolved. A sig- operating in a rich mode and the catalyst has notnificant portion of HC and CO emissions are gen- yet reached its light-off temperature. There areerated during cold starts, when the fuel system is many feasible technological improvements on the
CLEiN FUELS FOR ASIA: TECNICAL OP7ONS FOR MOPING TowARDs UMNEADED GAsoUNE AND Lo w-S UURDIESEL 74
horizon that are expected to control HC and CO CARB's new onboard diagnostics requirementemissions more stringently, not only reducing will enable the system to alert the driver whenemissions levels in new vehicles, but also emis- something is wrong with the emissions controlsions for vehicles in service. system and will help the mechanic to identify the
malfunctioning component.Increased use of fuel injection. The trend to- Improvements to the fuel control and ignitionward increased use of fuel injection has several systems, such as increasing the ability to main-distinct advantages over carburetion as a fuel con- tain a stoichiometric air/fuel ratio under all op-trol system, including more precise control of fuel erating conditions, and minimizing the occur-metering, better compatibility with digital elec- rence of spark plug misfire, will result in bettertronics, better fuel economy, and better cold-start overall catalyst conversion efficiency and lessfunction. Fuel metering precision is important in opportunity for catastrophic failure. These im-maintaining a stoichiometric air/fuel ratio for ef- provements, therefore, have a two-fold effect: (i)ficient three-way catalyst operation. Efficient limiting the extra engine-out emissions that wouldcatalyst operation, in turn, reduces the need for be generated by malfunctions, and (ii).helping todual-bed catalysts, air injection, and EGR. Bet- keep the catalyst in good working condition.ter driveability from fuel injection has been a mo- SeVeral alternative catalyst configurations willtivation to convert engines from carburetion to probably be used in the future to meet lower emis-fuel injection. In fact, it has been projected that sions standards. It is also likely that dual-bed cata-the percentage of new California light-duty ve- lysts will be phased out, and a warm-up catalysthicles with fuel-injectionwillreach95 percentby (preceding the thermal warm-up catalyst ortheearly 1990s, with 70 percent being multi-point. TWC) will be used for cold-start HC control. ToBecause of fuel injection systems' inherently avert thermal damage and lower the catalyst de-better fuel control, this trend is highly consistent terioration rate, this small catalyst will probablywith more stringent emissions standards. be bypassed at all times except during cold starts.
Fuel injection's compatibility with onboard Warm-up air injection could also be used with aelectronic controls enhances fuel metering pre- single-bed TWC for cold-start HC control. Ascision, and also gives manufacturers the ability HC standards are lowered, preheated catalyststo integrate fuel and emissions control systems will probably become more important for manyinto an overall engine management system. This cars' pollution control systems.permits early detection and diagnosis of malfunc-tions, automatic compensation for altitude, andto some degree, adjustments for normal wear. Two- AND TIREE-WHEELED VEHICLES:Carburetor choke valves, long considered a tar- SPECIAL CONCERNSget for maladjustment and tampering, are re-placed by more reliable cold-start enrichment Two- and three-wheeled vehicles, especially mo-systems in fuel-injected vehicles. torcycles and auto-rickshaws, constitute a large
Closed-loop feedback systems are critical to portionofmotorizedvehiclesindevelopingcoun-maintaining good fuel control. However, when tries, particularly in East and South Asia. Whilethey fail, emissions can increase significantly. In they are responsible for a relatively small fractionfact, CARB in-use surveillance data show that oftotal vehicle kilometers oftravel (VKT) in mostcomponent failure in a closed-loop system fre- countries, they often contribute substantially to airquently is associated with high emissions. pollution. This is especially true of motorcycles
75 APPENDIX B
and auto-rickshaws with two-stroke engines run- several additional advantages.ning on a mixture of gasoline and lubricating oil. Aldehydes are the most prevalent oxygenatedIthasbeen estimatedthatuncontrolledmotorcycles organic species in gasoline engine exhausts. Theyin industrialized countries emit 22 times as much tend to be highly photochemically reactive, andHC and 10 times as much CO as automobiles con- can cause serious eye irritation. One particulartrolled by U.S. 1978 levels.9 In Taiwan, HC emis- aldehyde-formaldehyde-has been found to besions from two-stroke engine motorcycles were carcinogenic in animal tests. These compounds13 times higher than emissions from new are effectively reduced by catalysts.four-stroke motorcycles, and over 10 times higherthanthe emissions from in-usepassengercars. CO Reactive hydrocarbons. Exhaust HC standardsemissions from two-stroke motorcycle engines are generally written in terms of total HCs. Cer-were similar to those from four-stroke engines.'° tain of these HCs, such as methane, are of less
Technologies available to control emissions environmental concern because they are chemi-from two- and three-wheeled vehicles are simi- cally stable and tend not to produce photochemi-lar to those available for other Otto cycle-pow- cal smog.2 However, since catalytic convertersered engines. Reducing the amount of lubricat- tend to selectively oxidize the more reactive HCs,ing oil in the fuel is one possible approach. a greater proportion of the HC species partici-Refining the fairly simple carburetors used would pating in the photochemical reactions leading tosignificantly reduce HC, CO, and smoke emis- smog will be reduced by catalysts.sions. Catalytic converters are also technologi-cally feasible for these engines." Polynuclear Aromatic Hydrocarbons (PAHs).
Many modern engines use a separated lubri- Emissions from this class of HCs are of particu-cation system which uses leaner fuel/oil ratios, lar interest because of their direct carcinogenicand therefore reduces smoke. Since 1986 mopeds effects on specific PAH compounds that havewith catalysts have been available in Austria and been detected in vehicle exhaust. Most notableSwitzerland. In Taiwan motorcycles have been among the PAHs is benzo(a)pyrene (BaP), a five-similarly equipped since 1992. ring aromatic that has been shown in a number
High smoke andunburnedHCs from two-stroke of experiments to be an animal carcinogen.engines are no longer technologically necessary. PAH emissions from gasoline-powered carsNew technology promises to resolve these con- are reduced substantially by controls designed tocerns. Direct cylinder electronic fuel injection, reduce HC and CO, and catalytic converters canelectronic computer control, and catalytic exhaust almost eliminate them.conversion are now common solutions. In addi-tion, advanced two-stroke engines, such as thosebeing developed by the U.S. firm Orbital indi- ENDNOTEScate that these engines can be even cleaner andmore fuel-efficient than four-stroke engines. 1. European Conference of Ministers of Trans-
port. 1990. Transport Policy and the Envi-ronment. Organization of Economic Coopera-
ADD1TIONALIHEALTH BENEFmS FROM CATALYSTS tion and Development: Paris.2. European Conference of Ministers of Trans-
In addition to significant improvements in CO, port. 1990. Transport Policy and the Envi-HC, and NOX emissions, emissions catalysts have ronment. Organization of Economic Coopera-
CLEAN FuEs FOR ASA. TECHNICAL OPONs FOR MoviNG TowARDs UNLEADED GASOLUNE AND Low-SFUR DIESEL 76
tion and Development: Paris. tal Protection Agency. 1988. Mobile Source3. European Conference of Ministers of Trans- EmissionsStandardsSummary. Washington, D.C.
port. 1990. Transport Policy and the Envi- 9. Organization of Economic Cooperation andronment. Organization of Economic Coopera- Development. 1988. Transport and Environ-tion and Development: Paris. ment, Paris.
4. Organization of Economic Cooperation and 10. Shen, S.-H., and K.-H. Huang, K-H. 1989.Development. 1988. Transport and Environ- "Taiwan Air Pollution Control Programme-ment, Paris. Impact of and Control Strategies for Trans-
5. French, H.F. 1990. "You Are What You portation-Induced Air Pollution." Bureau ofBreathe," World Watch. 3(3). Washington, Air Quality Protection and Noise Control, En-D.C. vironmental Protection Agency, Taiwan
6. European Conference of Ministers of Trans- (China).port. 1990. Transport Policy and the Envi- 1 1. Organization of Economic Cooperation andronment. Organization of Economic Coopera- Development. 1988. Transport and Environ-tion and Development: Paris. ment, Paris.
7. Organization of Economic Cooperation and 12. While not a direct health concern in the ur-Development. 1988. TransportandEnviron- ban environment, methane, one of the gasesment, Paris. accumulating in the upper atmosphere, is an
8. Office of AirandRadiation, U.S. Environmen- important potential greenhouse gas.
APPENDIX C: CONTROLS ON DIESEL-FUELED
VEHICLES
Diesel engine emissions are determined by the Common approaches to emissions control re-characteristics of the combustion process within quire a series of diesel engine modifications in-each cylinder. Primary engine parameters affect- cluding fuel injection, electronic engine controls,ing diesel emissions are the fuel injection sys- combustion chamber modifications, air handlingtem, engine control system, air intake port and characteristics, reduced oil consumption,combustion chamber design, and the air charg- turbocharging, injection retard, exhaust gas re-ing system. Actions to reduce lubricating oil con- circulation (EGR), and reduced heat rejectionsumption can also impact hydrocarbon (HC) and (ECMT 1990).particulate (PM) emissions. Beyond the engine Efficient combustion through improved mix-itself, exhaust aftertreatment systems such as trap ing of air and fuel results in lower HC and smokeoxidizers and catalytic converters can play a sig- emissions. Electronic control of fueling levels andnificant role. Finally, modifications to conven- timing, combined with high-pressure fuel injec-tional fuels, or alternative fuels, can substantially tion systems, can be quite beneficial.lower or raise emissions. The following sections Turbocharging increases NOX emissions but re-will review the status of each technology area, as duces particulates. Charge cooling (cooling thechapter 5 summarized the fuel impacts. intake air after the turbochargers) directly reduces
Except for PM, exhaust emissions (particu- NOX emissions by reducing peak cycle tempera-larly HC and carbon monoxide) from diesel en- tures and pressures. Injection retard is the mostgines are quite low compared to gasoline engines; effective way of reducing NO° emissions, buttherefore much of the attention to diesel exhaust increases fuel consumption, smoke, and HC emis-emissions has focused on PM and nitrogen oxide sions, particularly under light loading. EGR can(NOx) emissions. PM from diesel exhaust con- significantly reduce NOx but may double particu-sists of soot, condensed HCs, sulfur-based com- late emissions. Effective control of lubricatingpounds, and other oil-derived material. Smoke oil through engine design prevents it from enter-is the immediately visible portion of particulate ing the engine piston rings, valve guides or tur-emissions, and its opacity depends on the num- bochargers, and has been shown to reduce HCber and size of carbon particles present. The main emissions by about 50 percent (ECMT 1990).cause of black smoke is poor maintenance of air In order to achieve low levels of particulatefilters or fuel injectors. Fuel quality can also af- emissions, manufacturers have also developedfect smoke emissions, through fuel density, aro- exhaust treatment devices that are added to cleanmatic content, and certain distillation character- up the exhaust after it leaves the engine. Severalistics (T. J. Russell, 1989, ECMT, 1990). devices are being evaluated. One is a
Most the techniques for reducing PM and HC flow-through catalytic converter designed to op-emissions from diesel engines also improve com- erate on low-sulfur fuel. This may reduce thebustion efficiency and are fuel efficient. How- soluble organic fraction of particulates by asever, they result in higher NO, exhausts. much as 90 percent, and may also reduce the car-
77
CLEAN FuELs FOR AsIA: TECHNICAL OP2IONS FOR MOYING TowARDs UMEADED GASOLINE AND Low-SULFUR DiESEL 78
bon portion. Another, probably more promising engines typically use moderate to high injectionaftertreatment device, is the trap oxidizer con- pressures, and three to five spray holes per nozzle.trol system, which has demonstrated particulate Low-swirl engines rely primarily on the fuel in-control efficiencies, in some instances, of over jection process to supply the mixing. They typi-90 percent. cally have very high fuel injection pressures and
six to nine spray holes per nozzle.In the IDI engine, much of the fuel/air mixing
ENGINE MODIFICATIONS is due to the air swirl induced in the prechamberas air is forced into it during compression, and to
Air Motion and Combustion Chamber Design the turbulence induced by the expansion out ofthe prechamber during combustion. These en-
The geometries, of the combustion chamber and gines typically have better high-speed perfor-air intake port control the air motion in the diesel mance than DI engines, and can use cheaper fuelcombustion chamber, and thus play an impor- injection systems. Historically, IDI diesel enginestant role in air/fuel mixing and emissions. A num- have exhibited lower emissions levels than DIber of different combustion chamber designs, cor- engines, but with recent developments in DI en-responding to different basic combustion systems, gine emissions controls this is no longer the case.are presently being used in heavy-duty diesel Disadvantages of the IDI engine are the extra heatengines. This section outlines the basic combus- and frictional losses due to the prechamber, re-tion systems in use, their advantages and disad- sulting in a 5-10 percent reduction in fuel effi-vantages, and the effects of changes in combus- ciency compared to a DI engine.tion chamber design and air motion on emissions. A number of advanced, low-emitting, and
fuel-efficient high swirl DI engines have recentlyCombustion Systems been introduced; it appears that these engines will
completely replace existing IDI designs.Heavy-duty diesel engines use several differenttypes of combustion systems. The most funda- Direct Injection Combustion Chamber Designmental difference is between direct injection (DI)engines and indirect injection (IDI) engines. In Changes in the engine combustion chamber andan IDI engine, fuel is injected into a separate related areas demonstrate potential emissions re-"prechamber," where it mixes and partly burns ductions. Design changes to reduce the crevicebefore jetting into the main combustion cham- volume inDI diesel cylinders increasethe amountber above the piston. In the more common DI of air available in the combustion chamber.engine, fuel is injected directly into a combus- Changes in combustion chamber geometry-suchtion chamber hollowed out of the top of the pis- as the use of a reentrant lip on the piston bowl-ton. DI engines can be further divided into high- can markedly reduce emissions by improving air/swirl and low-swirl. fuel mixing and minimizing wall impingement
Fuel/air mixing in the DI engine is limited by by the fuel jet. Optimizing the intake port shapethe fuel injection pressure and any motion im- for best swirl characteristics has also yielded sig-parted to the air in the chamber as it enters. In nificant benefits. Several manufacturers are con-high-swirl DI engines, a strong swirling motion sidering variable swirl intake ports to optimizeis imparted to the air entering the combustion swirl characteristics across a broader range ofchamber by the design of the intake port. These engine speeds.
79 APPENDIX C
The crevice volume is a part of the compression Optimal matching of the intake air swirl ratiovolume lying outside the combustion chamber. with combustion chamber shape and other vari-This includes the clearance between the top of ables is critical for emissions control in high-swirlthe piston and the cylinder head, and the "top engines. The swirl ratio is the ratio of the rota-land"-the space between the side of the piston tional speed of the air charge in the cylinder to theand the cylinder wall above the top compression rotational speed of the engine-determined by thering. The smaller the crevice volume, the larger design of the air intake port. The selection of athe combustion chamber volume can be for a fixed swirl ratio involves some trade-offs betweengiven compression ratio, effectively increasing low-speed and high-speed performance. At lowthe amount of air available for combustion. speeds, a higher swirl ratio provides better mix-
The major approaches to reducing the crevice ing, permitting more fuel to be injected and thusvolume are to reduce the clearance between the greater torque output at the same smoke level.piston and cylinder head through tighter produc- However, this can result in too high a swirl ratiotion tolerances, and moving the top compression at higher speeds while impairing the airflow toring toward the top of the piston. This increases the cylinder. Too high a swirl ratio can also in-the top ring's working temperature, and poses me- crease HC emissions, especially under light loads.chanical design problems for the piston top and Attaining an optimal swirl ratio is more diffi-cooling system. These problems have been ad- cult in smaller engines because they experiencedressed through redesign and the use of more ex- a wider range of engine speeds than heavy en-pensive materials. The higher piston ring tempera- gines. One solution to this problem is to vary theture may also make additional demands on the oil. swirl ratio as a function of engine speed. A two-
position variable swirl system has been devel-In high-swirl DI engines, are-entrantcombustion oped and applied to some diesel engines in Ja-chamber shape (where the lip of the combustion pan, and is being considered for engines used inchamber protrudes beyond the walls of the bowl) the United States as well. Test data using thisprovides a substantial improvement in perfor- system show a noticeable reduction in PM andmance and emissions over the previous straight- NO emissions due to optimization of the swirlsidedbowl designs. Researchers atAVL List (Aus- ratio at different speeds.tria) found that a re-entrant bowl gave a 20 percentreduction in PM emissions comparedto those mea- Fuel Injectionsured from a straight-sided bowl at the same com-pression ratio. NO emissions increased 3 per- The fuel injection system is one of a dieselcent, but the re-entrant bowl combustion chamber engine's most important components. It includeswas found to be more tolerant of retarded injec- the process by which the fuel is transferred fromtion timing than the straight-sided bowl. the fuel tank to the engine, and the mechanism
Because of the superiority of the re-entrant by which it is injected into the cylinders. Thebowl design in high-swirl engines, nearly all manu- fuel injection's precision, characteristics, and tim-facturers of such engines are developing or al- ing determine the engine's power, fuel economy,ready using this approach. Similar improvements and emissions characteristics.in the performance of low-swirl DI engines may The fuel injection system normally consistsalso be possible through modifications to com- of a low-pressure pump transferring fuel frombustion chamber geometry, but there is little the tank to the engine; one or more high-pres-agreement on what the optimal shape should be. sure fuel pumps creating the pressure pulses that
CLsAN FuELs FOR ASIA: TEcHANcAL OPnONs FOR MONNG TowARDs UMAEADED GASOLINe AND Low-SuFYuR DrESEL 80
send the fuel into the cylinder; the injection and pumping element for each cylinder is com-nozzles where fuel is injected into the cylinder; bined in the same unit with the injection nozzleand a governor and fuel metering system. These at the top of the cylinder. The pumping elementsdetermine how much fuel is injected on each in a unit injector system are generally driven bystroke, and thus the power output of the engine. the engine camshaft.
The major areas of concentration in fuel in- Worldwide, many more engines are made withj ection system development are increased inj ec- pump line nozzle injection systems than with unittion pressure, increasingly flexible control of in- injectors, due primarily to the higher cost of unitjection timing, and more precise governing of injector systems. Presently, three U.S. enginethe fuel quantity injected. Systems offering elec- manufacturers (accounting for more than half oftronic control of these quantities and fuel injec- U.S. heavy-duty engine production) produce unittion rate have been introduced. Some manufac- injector-equipped truck engines. Due to the ab-turers are also pursuing technology to vary the sence of high pressure fuel lines, unit injectorsrate of fuel injection over the injection period in are capable of higher injection pressures thanorder to reduce the amount of fuel burning in the pump line nozzle systems. With improvementspremixed combustion phase. Reductions in NOX in electronic control, these systems offer betterand noise emissions, and maximum cylinder pres- fuel economy at low emissions levels than thesures have been demonstrated using this ap- pump line nozzle systems. For this reason, manyproach. Other changes have been made to the heavy-duty engine models sold in the Unitedinjection nozzles themselves to reduce or elimi- States were equipped with unit injectors for thenate sac volume, and to optimize the nozzle hole 1991 model year.size and shape, number of holes, and spray anglefor minimum emissions. Fuel injection pressure and injection rate.
High fuel injection pressures are desirable in or-Injection system types. Fuel injection systems der to improve fuel atomization and fuel/air mix-used in heavy-duty diesel vehicles can be divided ing, and to offset the effects of retarded injectioninto two basic types. The most common type con- timing by increasing the injection rate. It is wellsistsofasinglefuelpump(typicallymountedatthe established that higher injection pressures reduceside of the engine) which is driven by gears from PM and smoke emissions. High injection pres-the crankshaft, and connected to individual inj ec- sures are most important in low-swirl direct in-tion nozzles at the top of each cylinder by special j ection engines, since the fuel injection system ishigh-pressure fuel lines. These pump line nozzle responsible for most of the fuel/air mixing in theseinjection systems can be further divided into two systems. For this reason, low-swirl engines tendsubclasses: distributor fuel pumps, in which a to use unit injector systems, that can achieve peaksinglepumpingelementismechanicallyswitched injection pressures in excess of 1,500 bar.to connect to the high pressure fuel lines for each The injection pressures achievable in pump linecylinder in turn; and in line pumps, having one nozzle fuel injection systems are limited by thepumping element per cylinder where each is con- mechanical strength of the pumps and fuel lines,nectedto its own high pressure fuel line. The latter as well as by pressure wave effects, to about 800type is much more common in heavy-duty trucks. bar. Improvements in system design to minimize
The most common alternative to the pump line pressure wave effects, and increases in the sizenozzle injection systems are systems using unit and mechanical strength of the lines and pump-injectors, in which the individual fuel metering ing elements have increased the injection pres-
81 APPENDIX C
sures achievable in pump line nozzle systems sub- scribed in the technical literature, but to date, suchstantially from those achievable a few years ago. systems were introduced in the US in 1991.
The pumping elements in all current fuel in-jection systems are driven through a fixed me- Initial injection rate and premixed burning.chanical linkage from the engine crankshaft. This Reducing the amount of fuel burned in themeans that the pumping rate, and thus the injec- premixed combustion phase can significantlytion pressure, is a strong function of engine speed. reduce total NO, emissions. This can be achievedAt high speeds the pumping element moves rap- by reducing the initial rate of injection whileidly, and injection pressures and injection rates keeping the subsequent rate of injection high toare high. Conversely, at lower speeds, the injec- avoid high PM emissions due to late burning. Thistion rate is proportionately lower, and injection requires varying the rate of injection during thepressure drops off rapidly. This poor atomiza- injection stroke. While this represents a difficulttion and mixing at low speeds can be a major design problem for mechanical injections sys-cause of high smoke emissions during lugdown. tems, it still should be possible usingIncreasing the pumping rate to provide adequate electro-hydraulic injectors. Another approach topressure at low speeds is impractical, as it would the same end is split injection where a smallexceed the system pressure limits at high speed. amount of fuel is injected in a separate event
A new type of in-line injection pump which ahead of the main fuel injection period.provides a partial solution to this problem, has Data published by a U.S. manufacturer show arecently been developed. The cam driving the marked beneficial effect from reducing the initialpumping elements in this pump has a non-uniform rate of injection. Based on these data, it appearsrise rate. This allows the pumping rate (at any likely that a 30-40 percent reduction in NO emis-given time) to be a function of the cam angle. By sions could be achieved through this technique with-electronically adjusting a spill sleeve, it is pos- out significant adverse impacts on fuel consump-sible to select the portion of the cam's rotation tion or HC or PM emissions. As a side benefit,when fuel is injected, and vary the injection rate. engine noise and maximum cylinder pressures (forInjection timing varies at the same time, but the a given power output) would also be reduced.system is designed for the desired injection rateand injection timing to correspond fairly well. Low sac/sacless nozzles. The nozzle sac is a smallIshida and co-workers obtained a 25 percent re- internal space in the tip of the injection nozzle.duction in PM emissions, and a 10 percent re- The nozzle orifices open into the sac so that fuelduction in HC using this system with virtually flowing past the needle valve first enters the sac,no increase in NOX. The same approach could then sprays out the orifices. The small amount ofeasily be applied to a unit injector system using fuel remaining in the sac tends to burn or evapo-an electronically controlled spill valve. rate late in the combustion cycle, resulting in sig-
Another approach to increasing injection pres- nificant PM and HC emissions. The sac volumesure at low engine speeds is using can be minimized or even eliminated by rede-electro-hydraulic actuators for injection instead signing the injector nozzle. One manufacturerof mechanically-driven pumping elements. reported nearly a 30 percent reduction in PMThrough appropriate design and control schemes, emissions through elimination of the nozzle sac.such systems can control and maintain fuel in- It is also possible to retain some of the sac whilejection pressures almost independently of engine designing the injector nozzle so that the tip ofspeed. A number of such systems have been de- the needle valve covers the injection orifices
CLESoN FuE.s FOR AsIA: TECHMCAL OPONS FOR MOnNG TowARDs UNLEADED GASOLNE AND LOW-SuLFUR DIESEL 82
when it is closed. This valve covers orifice (VCO) Many pump line nozzle fuel injection systemsinjector design is used in some production en- incorporate mechanical injection timing controls.gines, and in many engines was developed to Since the injection pump is driven by a specialcomply with 1991 U.S. emissions standards. shaft geared to the crankshaft, injection timing
can be adjusted within a limited range by vary-Engine Control Systems ing the phase angle between the two shafts using
a sliding spline coupling. A mechanical or hy-Traditionally diesel engine control systems have draulic linkage slides the coupling back and forthbeen closely integrated with the fuel injection in response to engine speed or load signals.system, enabling the two systems to be discussed In mechanical unit injector systems, the in-together. These earlier control systems (still used jectors are driven by a direct mechanical linkagein most engines) are entirely mechanical. The last from the camshaft, making it very difficult to varyfew years have seen the introduction of an in- the injection timing. Cummins, in its Californiacreasing number of computerized electronic con- engines, has introduced a mechanical timing con-trol systems for diesel engines. With the intro- trol which operates by moving the injector camduction of these systems, the scope of the engine followers back and forth with respect to the cam.control system has been greatly expanded. Although effective in limiting light-load HC and
PM emissions under stringent California NO,Most current diesel engines still rely on mechani- standards, these systems have proven troublesomecal engine control systems. The primary func- and unpopular among users.tions of these systems include basic fuel meter-ing, engine speed governing, maximum power Computerizedelectronicenginecontrolsystemslimitation, torque curve "shaping," limiting have greatly increasedthepotential flexibility andsmoke emissions during transient acceleration, precisionoffuelmeteringandinjectiontiming con-and often, limited control of fuel injection tim- trols. Inaddition,wholenewcontrolfunctionshaveing. Engine speed governing is accomplished been made possible, such as road speed govern-through a spring and flyweight system which ing, alterations in control strategy during transients,progressively (and quickly) reduces the maxi- synchronous idle speed control, and adaptive learn-mum fuel quantity as engine speed exceeds the ing. This includes strategies to identify and com-rated value. The maximum fuel quantity itself is pensate for the effects of wear, and component togenerally set through a simple mechanical stop component variation in the fuel injection system.on the rack controlling injection quantity. More By continuously adjusting the fuel injectionsophisticated systems allow some "shaping" of timing to match a stored "map" of optimal timingthe torque curve to change the maximum fuel versus speed and load, an electronic timing con-quantity as a function of engine speed. trol system can significantly improve on the NOX/
Acceleration smoke limiters are needed to pre- particulate and NOX/fuel economy trade-offs pos-vent excessive black smoke emissions during sible with static or mechanically variable injec-transient acceleration of turbocharged engines. tion timing. Most electronic control systems alsoMost of these engines are designed to limit the incorporate the functions of the engine governormaximum fuel quantity injected as a function of and the transient smoke limiter. This helps to re-turbocharger boost, so that full engine power is duce excess particulate emissions due to mechani-developed only after the turbocharger comes up cal friction and lag time during engine transients,to speed. while simultaneously improving engine perfor-
83 APPENDIX C
mance. PM emissions reductions of up to 40 per- cerned with increasing the turbocharger effi-cent have been documented w'ith this approach. ciency, operating range, and transient response
Other electronic control features such as cruise characteristics. This has been accompanied bycontrol, upshift indication, and communication improved intercoolers to further reduce the tem-with an electronically controlled transmission will perature of the intake charge. Tuned intake airalso help to reduce fuel consumption, and will manifolds (including some with variable tuning)thus likely reduce in-use emissions. Since the have also been developed to maximize air intakeeffect of these technologies is to reduce the efficiency in a given speed range.amount of engine work necessary per mile, ratherthan the amount of pollution per unit of work, Turbocharger refinements. Turbochargers fortheir effects will not be reflected in dynamom- heavy-duty diesel engines are already highly de-eter emissions test results. veloped, but efforts to improve their performance
continue. The major areas of emphasis are im-Turbocharging and Intercooling proved matching of turbocharger response char-
acteristics to engine requirements, improved tran-A turbocharger consists of a centrifugal air com- sientresponse, andhigher efficiencies. Engine andpressor feeding the intake manifold mounted on turbocharger matching is especially critical be-the same shaft as an exhaust gas turbine in the cause of the inherent conflictbetween the responseexhaust stream. By increasing the mass of air in characteristics of the two types of machines. En-the cylinder prior to compression, turbocharging gineboostpressurerequirements are greatestnearcorrespondingly increases the amount of fuel that the maximum torque speed, and most turbocharg-can be burned without excessive smoke, and thus ers are matched to give near optimal performanceincreases the potential maximum power output. at that point. At higher speeds, the exhaust flow-This also improves the engine's fuel efficiency. rate is greater, and the turbine power output is cor-The process of compressing the air, however, respondingly higher. Boost pressure under theseraises its temperature, increasing the thermal load circumstances can exceed the engine's designon critical engine components. By cooling the limits, and the excessive turbine backpressurecompressed air in an intercooler before it enters increases fuel consumption. Thus, some compro-the cylinder, the adverse thermal effects can be mise between adequate low speed boost and ex-reduced. In addition, the density of the air in- cessive high speed boost must be made.creases, and allows an even greater mass of airto be confined within the cylinder, thus further Variable geometry turbochargers (VGTs).increasing the maximum power potential. Because of the inherent mismatch between en-
Increasing the air mass in the cylinder and gine response and fixed geometry turbochargerreducing its temperature can reduce both NOX and characteristics, a number of engine manufactur-PM emissions as well as increase fuel economy ers are considering the use of variable geometryand power output from a given engine displace- turbines. In these systems, the turbine nozzles canment. Most heavy-duty diesel engines are pres- be adjusted to vary the turbine pressure drop andently equipped with turbochargers, many of power level in order to match the engine's boostwhich have intercoolers. In the United States, all pressure requirements. Thus, high boost pressuresengines were equipped with these systems by can be achieved at low engine speeds without1991. Recent developments in air charging sys- wasteful overboosting at high speed. The resulttems for diesel engines have been primarily con- is a substantial improvement in low speed torque,
CLEAIN FuELs FOR AsI: TEC1NMCAL OPIToNs FOR AMOVING TowARDs UNEADED GASOLINE AND Low-SuLFuR DIEsEL 84
transient response, and fuel economy, and a re- mounted on the truck chassis in front of the ra-duction in smoke, NON, and PM emissions. diator. Although bulky and expensive, these
Prototype VGTs have been available for some charge air coolers are able to achieve the lowesttime, but they have not been used in production charge air temperatures-in many cases, onlyvehicles. The major reasons for this are their cost 10-1 5°C above ambient. An alternative approach(as much as 50 percent more than a comparable is low temperature air-to-water intercooling,fixed geometry turbocharger), reliability con- which in the United States has been studied bycems, and the need for a sophisticated electronic Cummins Engine. Cummins has chosen to retaincontrol system to manage them. With the forth- the basic water air intercooler, but with drasti-coming deployment of electronic engine controls cally reduced radiator flowrates to reduce theon virtually all U.S. vehicles, these arguments water temperature coming from the radiator. Thishave lost much of their force. VGTs' fuel water is then passed through the intercooler be-economy and performance advantages are great fore it is used for cooling the rest of the engine.enough to outweigh the costs in many applica-tions. As a result, VGTs should be available on a Intake Manifold Tuningnumber of production heavy-duty diesel enginesin the near future. Tuned intake manifolds have been used for many
years to enhance airflow rates on high-perfor-Other types of superchargers. A number of al- mance gasoline engines, and are being consideredternative forms of supercharging have been stud- for some heavy-duty diesel engines. A tuned mani-ied with respect to overcoming the mismatch fold provides improved airflow and volumetricbetween turbocharger and engine response char- efficiency at speeds near its resonant frequency,acteristics. The two leading candidates at present although at the cost of reduced volumetric effi-are the Sulzer ComprexTM gas dynamic super- ciency at other speeds. At least one medium- andcharger, and mechanically assisted turbocharg- heavy-duty manufacturer is considering a vari-ers, such as the "three wheel" turbocharger de- able resonance manifold in order to improve air-veloped by General Motors. The maj or flow characteristics at both low and high speeds.advantages of these systems are superior low-speed performance and improved transient re- Lubricating Oil Controlsponse. These advantages would be expected toyield some improvement in PM emissions, as well A significant fraction of diesel PM (10-50 per-as driveability and torque rise. cent) consists of oil-derived HC and related solid
Presently, most intercoolers rely on the en- matter. Reduced oil consumption has been a de-gine cooling water as a heat sink, since this mini- sign goal of heavy-duty diesel engine manufac-mizes the components required. However, this turers for some time, and the current generationwater's relatively high temperature (about 90°C) of diesel engines already uses fairly less oil thanlimits the benefits available. For this reason, an its predecessors. Further reductions in oil con-increasing number of heavy-duty diesel engines sumption are possible through careful attentionare being equipped with low-temperature charge to cylinder bore roundness and surface finish,air cooling systems. optimization of piston ring tension and shape,
The most common type of low-temperature attention to valve stem and turbocharger oil seals,charge air cooler emits heat directly to the atmo- and other possible sources of oil loss. However,sphere through an air-to-air heat exchanger present technology requires some oil consump-
85 APPENDIX C
tion in the cylinder, for its lubricating and corro- of course, much less than that of a trap. How-sion protective functions. ever, a PM control efficiency of even 25-3 5 per-
Advances in piston and cylinder tribology cent is enough to bring many current enginescould potentially eliminate or greatly reduce oil within existing emissions standards.consumption in the cylinder. Areas such as Diesel catalytic converters have a number ofboundary lubrication and development of low advantages. First, in addition to reducing particu-friction ceramic coatings are presently the sub- late emissions, the oxidation catalyst greatly re-jects of much research. The potential for trans- duces HC, CO, and odor emissions. The catalystisforming this research into durable and reliable also very efficient in reducing emissions of gas-engines on the road is yet to be demonstrated. eous and particle-bound toxic air contaminants
such as aldehydes, PNA and nitro-PNA. While aprecious metal-catalyzed particulate trap would
AFTERTREATMENT SYSTEMS have the same advantages, the catalytic converteris less complex, smaller, and cheaper. In addition,
In order to achieve very low levels of PM emis- the catalytic converter has little impact on fuelsions, manufacturers have developed exhaust economy or safety, and usually does not requirecontrol devices, cleaning up the exhaust after it replacement. Also, the catalytic converter is arela-leaves the engine. Several devices are available. tively mature technology-millions of catalyticOne is a flow-through oxidation catalytic con- converters are used in gasoline vehicles, and die-verter, installed on a vehicle designed to operate sel catalytic converters have been used in under-on low-sulfur fuel, which can reduce the particu- ground mining applications formorethan 20 years.lates' soluble organic fraction (SOF) by as much Potential sulfate emissions are a major disad-as 90 percent, and may reduce carbon as well. vantage of catalytic converters. Precious metalAnother is a trap oxidizer control system which catalysts' tendency to convert SO2 to particulatecan achieve 90 percent or even greater particu- sulfates requires the use of low-sulfur fuel. Oth-late reductions. Catalyst and trap technology can erwise, sulfate emissions increases would morebe combined to provide even greater control. Fi- than counterbalance the decrease in SOF. Fortu-nally, research and development on NO. nately, Europe, Japan, and the United States haveaftertreatment systems is taking place, and posi- already decided to reduce diesel fuel sulfur con-tive results are beginning to emerge. tent, making catalyst technology viable.
An oxidation catalyst causes chemical reac-Catalytic Converters tions without being changed or consumed. An
oxidation catalytic converter consists of a stain-A diesel catalytic converter oxidizes a large part less steel canister that typically contains aof the SOF's HC constituents, as well as gaseous honeycomb-like structure called a substrate.HC, carbon monoxide (CO), odor-creating com- There are no moving parts, just interior surfacespounds, and mutagenic emissions. Unlike a cata- on the substrate coated with catalytic metals suchlytic trap, a flow-through catalytic converter does as platinum or palladium. It is called an oxidiz-not collect any of the solid PM. This simply ing catalyst because it transforms the pollutant,passes through in the exhaust. This eliminates the in this case SOF, into harmless gases by means ofneed for a regeneration system with its attendant oxidation. The oxidation catalyst has been opti-technical difficulties and costs. The particulate mized so that engine durability and reliability arecontrol efficiency of the catalytic converter is, unaffected, and no fuel penalties will occur.
Ci-AN FuEas FOR ASIA: TECHMCAL OP2iONS FOR MOVING TowARDs UNLEADED GASOLrAE AND Low-SVZFuR DIESEL 86
Oxidation catalysts are able to control a sig- groups-passive and active systems. Passive sys-nificant portion of particulate SOF. For example, tems must attain conditions required for regenera-one study reported that oxidation catalysts could tion during normal vehicle operation. The mostreduce particulate SOF by 90 percent under cer- promising approaches require a catalyst (either astain operating conditions, and could reduce total acoatingonthetrap oras afuel additive) inordertoparticulate emissions by 40-50 percent. SOF reducethecollectedPMignitiontemperature. Re-destruction is important since these emissions generationtemperaturesaslow as 420C have beencontain numerous chemical pollutants of particu- reported with catalytic coatings, and even lowerlar concern to health experts. Another benefit of temperatures are achievable with fuel additives.the oxidation catalyst is that it also controls gas- Active systems monitor PM buildup on the trap,eous hydrocarbon and CO emissions in exhaust and trigger specifilc regeneration actions whenby 80-90 percent. Finally, catalysts noticeably needed. A wide variety of regeneration triggersreduce diesel exhaust odor. have been proposed such as diesel fuel burners,
electric heaters, and catalyst injection systems.Trap Oxidizers or Filters Passive regeneration systems face special prob-
lems from heavy-duty vehicles. Exhaust tempera-A trap oxidizer system consists of a durable par- tures from heavy-duty diesel engines are normallyticulate filter (the "trap") positioned in the en- low, and recent developments such as charge airgine exhaust stream, along with some means for cooling and increased turbo charger efficiencycleaning the filter by burning off ("oxidizing") reduce them further. Under some conditions, itthe collected PM. Building a filter capable of col- would be possible for a truck to drive for manylecting diesel soot and other PM from the ex- hours without exceeding the exhaust temperaturehaust stream is a straightforward task, and a num- (400-450'C) required to trigger regeneration.ber of effective trapping media have been Engineandcatalystmanufacturershaveexperi-developed and demonstrated. The most challeng- mented with a wide variety of catalytic materialsing problem of trap oxidizer system development and treatments to assist in trap regeneration. Goodwas the process of "regenerating" the filter by results have been obtained both with preciousburning off the accumulated PM. metal (platinum, palladium, rhodium, silver) and
Diesel PM consists primarily of a mixture of base metal (vanadium, copper) catalysts. Precioussolid carbon coated with heavy HCs. The ignition metal catalysts are effective in oxidizing gaseoustemperature of this mixture is about 500-600°C, HC and CO and particulate SOF, but are rela-which is above the normal range of diesel engine tively ineffective at promoting soot oxidation.exhaust temperatures. Thus, special means are Unfortunately, these metals also promote the oxi-needed to assure regeneration. Furthermore, once dation of SO2 to particulate sulfates such as sul-ignited, this material burns at very high tempera- furic acid (H2SO4). In contrast, the base metaltures which can easily melt or crack the particu- catalysts are effective in promoting soot oxida-late filter. Initiating and controlling the regen- tion, but have little effect on HC, CO, NOX oreration process to ensure reliable regeneration SO2. Many experts believe, that ultimately, pre-without damaging the trap is the central engi- cious metal catalysts must be an important ele-neering problem of trap oxidizer development. ment of an effective particulate control system
Numeroustechniquesforregeneratingparticu- because it specifically attacks the "bad actors."late trap oxidizers have been proposed These ap- Catalyst coatings also have a number of ad-proaches can generally be divided into two vantages in active systems. The reduced ignition
87 APPENDIX C
temperature and increased combustion rate (due The bypass operates infrequently and only for ato the catalyst) mean that the regeneration sys- very short time. Systems also have been designedtem needs less energy. Regeneration will also with dual filters-one filter collects while theoccur spontaneously under most duty cycles, other is being regenerated.greatly reducing the number of times the regen- Traps are being further developed for optimiz-eration system must operate. The spontaneous ing regeneration systems which are simple, reli-regeneration capability also provides some in- able and reasonably priced to demonstrating du-surance against regeneration system failure. Fi- rability ofthe trap system in real world operation.nally, the use of a catalyst may make a simplerregeneration system possible. Nitrogen Oxide Reduction Techniques
Although normal heavy-duty diesel exhausttemperatures are not high enough under all oper- Under certain conditions NO° can be chemicallyating conditions to provide reliable regeneration reduced to form gaseous oxygen andnitrogen. Thisfor a catalyst-coated trap, exhaust temperature can process is used in modem closed-loop three-wayeasily be increased by changing engine operating catalyst-equipped gasoline vehicles to control NOxparameters. Retardingtheinjectiontiming, bypass- emissions. However, catalytic NO, reduction asingthe intercooler, throttlingthe intake air (or cut- used in gasoline vehicles is inapplicable to die-ting back on a variable geometry turbocharger), sels. Because of their heterogeneous combustionor increasing the EGR rate will increase the ex- process, diesel engines require substantial excesshaust temperature dramatically. Applying these air, and their exhaust inherently contains signifi-measures consistently would seriously degrade cant excess oxygen. The three-way catalysts usedfuel economy, engine durability, and perfor- on automobiles require a precise stoichiometricmance. However, an electronic control system mixture in the exhaust in order to function. Incan selectively apply these measures to regener- the presence of excess oxygen, their NOx con-ate the trap. In addition, since they are normally version efficiency rapidly approaches zero.needed only at light loads, effects on durability A number of aftertreatment NOx reductionand performance should be imperceptible. techniques which work in an oxidizing exhaust
Fuel additives may play a key role in trap- stream are currently available or under develop-based systems, although concerns have been ment for stationary pollution sources. These in-raised about metallic additives' possible toxic- clude selective catalytic reduction (SCR); selec-ity. Cerium-based additives have not yet raised tive non-catalytic reduction (Thermal DenoxT4);these concerns, and recent studies of buses in and reaction with cyanuric acid (RapReNoxTm).Athens, Greece, have shown encouraging results. However, each of these systems requires a con-These additives were able to lower engine-out tinuous supply of some reducing agent, such asparticulate emissions as well as facilitate regen- ammonia or cyanuric acid, to react with the NOX.eration. Ongoing studies in South Korea continue Because this agent needs to be frequently replen-to show high promise also. Further analysis of ished, and it is difficult to ensure that the replen-health effects assessment may be required for ishment is performed when needed, such systemscerium-based additives, are considered impractical for vehicular use.
In order to protect the filter from overheating AreportpreparedbyAcurex(undercontracttoand possible damage, some trap systems have a the California Air Resources Board), "Technicalexhaust gases bypass which is triggered only FeasibilityofReducingNOxandParticulateEmis-when exhaust temperatures reach critical levels. sions From Heavy-Duty Engines," concluded that
CLEAN FUELs FoR AsA: TECHNICAL OPIoNsFoR MIovNG TowA.RDs ULEA.DED GASOLINE AAD Low-SUEFUR DIESEL 88
NO,canpotentiallybereduced aslowas 2.5 grams available option for urban bus engines rebuiltperBHP-hr. Thisstandardwouldrequireacombi- under USEPA's bus rebuild requirements.nation of some or all of the following emissions NOX reduction catalysts (DeNOX catalysts),control approaches: very high pressure fuel injec- currently at the prototype stage, offer the poten-tion, variable geometry turbocharging, air-to-air tial for considerably lower NOx emissions, andaftercooling, optimized combustion, electronic may begin to be applied to some vehicle modelsunit injections with minimized sac volumes, rate over the next few years."2shaping, exhaust gas recirculation, and sophisti- By the year 2000, further improvements willcated electronic control of all engine systems. have to be made to all passenger car diesel en-Such controls would substantially increase cost gines in order to attain proposed standards-0.04and fuel consumption. Most of the devices de- grams per kilometer of PM and 0.5 grams perscribed in the Acurex report are in relatively early kilometer each of HC and NO . "To achievestages of development and would require exten- [these levels,] both engine types, the ID and thesive changes in heavy-duty diesel-powered en- DI, must be equipped with sophisticated emis-gines compared to today's designs. sions control systems which include:
* Electronically controlled injection system;Status of Aftertreatment Applications * Injection rate shaping (at least for the DI);
* Multi valve technology;In Europe, over 500,000 diesel automobiles each * Turbocharging;year are equipped with catalysts, and virtually all * Intercooling;new diesel cars sold in Austria, France, and Ger- * Controlled EGR; andmany come so equipped. Public demand for clean * Oxidation Catalyst"3
diesels and tax incentives are spurring the use of "Hydrocarbon levels of less than 0.03 gramsthese devices. "Oxidation catalysts can lower CO, per kilometer over the European emissions cycleHC and particulate emissions considerably, and are possible with a well optimized catalystalso improve the odor of diesel exhaust."' After equipped diesel car, which is comparable withStep 2 light duty vehicle standards are introduced, the requirements of the California Low Emissionsvirtually all new diesel light-duty vehicles sold Vehicle (LEV) standards."4
in Europe are expected to be equipped with at For heavy-duty vehicles, "[T]o comply withleast an oxidation catalyst by 1997. the European Stage III standards all engines are
In 1994, a number of U.S. engine manufactur- likely to feature 4 valve per cylinder combustioners offered catalyst-equipped trucks capable of systems, and very high pressure injection sys-meeting the 0.1 PM standard. Indeed, catalysts tems with injection pressure in excess of 1500are being used on a significant number of 1994 bar. These engines will also incorporate new tech-model year heavy-duty (8,500-33,000 pounds nologies for NOX reduction, such as the use ofGVWR range) trucks to help manufacturers meet pilot injection or exhaust gas recirculation (EGR).tougher PM standards. Also, engine manufactur- If EGR is employed, significant problems asso-ers will use catalysts to meet the 0.07 bus stan- ciated with engine durability will need to be over-dard, and may be able to meet the 0.05 standard come. However, these engines will offer the pos-on some bus engines. Recently, 200 school buses sibility of achieving zero visible smoke under allwith Caterpillar 3116 engines were equipped with operating conditions.catalysts as part of a demonstration program spon- "To achieve standards projected beyond thesored by the California. Catalysts will also be an year 2000 there is already significant research
89 APPENDIX C
and development on NOx reduction (DeNOx) cent as a result of stringent exhaust emissionscatalysts. Development of particulate traps and limits. The techniques available for reducing NOxregeneration technology is also underway, and if emissions (primarily ignition retard and EGR)successful, this will enable further significant will lead to poor fuel economy; other enginereductions in exhaust particulate emissions."' improvements such as increased use of
Engine manufacturers throughout the world turbocharging and charge cooling, better controlare subjecting trap systems to a full range of of injection rates, and timing may offset some ofevaluation. In addition, devices continue to be the fuel efficiency losses.evaluated by other parties interested in diesel Additional equipment (e.g., charge coolers orparticulate control. particulate traps) needed to comply with exhaust
Trap oxidizers are not only being developed emissions requirements are likely to increase ve-for new vehicles, but also as a control device that hicle costs. More advanced equipment, such ascan be retrofitted to existing trucks and buses. In electronic fuel injection systems or variable ge-fact, traps already have been retrofitted on urban ometry turbochargers will increase costs initially,buses and fire trucks in a number of cities around but those costs should come down when suchthe world. equipment becomes standard. Vehicle mainte-
nance costs are not likely to increase except forparticulate traps, which have not yet been proven
EFFECT ON FUEL CONSUMPTION AND COSTS durable. Table C. 1 shows estimated cost increasesfor individual engine modifications that will be
Diesel vehicle fuel economy is likely to see an needed to meet future emissions standards.overall operating costs increase of about 2 per-
Table C. 1: Cost of Diesel Engine Exhaust Emissions Control Technology
Technology Estimated extra cost aspercent of engine first cost
(excluding development costs)
Baseline engine, no emissions control equipment. Developed for performance only. Nil
Injection tming retard Nil
Low sac volume/valvecovering orifice nozzle Minimal
Turbocharging 3-5 percent
Charge cooling 5-7 percent
Improved high pressure fuel injection 13-15 percent
High pressure fuel injection with electronic control 14-16 percent
Variable geometry turbocharging (assuming already applied to engine) 1-3 percent
Particulate trap 4-25 percent
Source: European Conference of Ministers of Transport. 1990. "Transport Policy and the Environment."
CIEAN FuELs FOR AsIx: TECHICAL OPnoNs FOR MOVNG TowARs UmEADED GASoLNE AND LOW-S UIFUR DIESEL 90
ENDNOTES ment Trends under Future Boundary Condi-tions," SAE # 945001, Fisita 94.
1. Ricardo. 1994. "Automotive Diesel Engines 4. Ricardo. 1994. "Automotive Diesel Engines& the future." & the future."
2. Ricardo. 1994. Op. cit. 5. Ricardo. 1994. Op. cit.3. Pisching, F. 1994. "Vehicle Engine Develop-
APPENDIX D: INTERNATIONAL EMISSION AND
FUELS STANDARDS
Table D. 1: Canada and U.S. Tier I Emission Standards (1994-)-Light-Duty Vehicles andTrucks
Table D.2: U.S. Tier 1 Emission Standards (1994-)-Heavy-Duty Engines and Urban Buses
Table D.3: Exhaust Emissions, European Vehicles (1995 Representative Fleet)
Table D.4: E. U. Light-Duty Vehicle Emission Standards (1996-)
Table D. 5: E. U. Heavy-Duty Diesel Vehicle Emission Standards (1993-2000)
Table D. 6. South Korea Vehicle Emission Standards (1996)
Table D. 7: Current Exhaust Emissions Standards Republic of Singapore
Table D. 8: Diesel Driven Exhaust Emission Standards Republic of Singapore (effective July1997)
Table D. 9: Emission Standards for Japan
Table D. 10: Hong Kong New Vehicle Emisssion Standards (as of 1 April 1995)
Table D. 11: Hong Kong Automotive Fuel Speciflcations
Table D. 12: Malaysia Gasoline Vehicle Emissions Standards
Table D. 13: Malaysia Diesel Vehicle Emissions Standards
Table D. 14: International Vehicle Exhaust Emission Regulations-Automobiles
Table D. 15: International Vehicle Exhaust Emission Regulations-Light Duty Trucks
Table D. 16: International Vehicle Exhaust Emission Regulations-Heavy Duty Trucks
Table D. 17: Lead Added to Gasoline (1990-2000)
91
CLEAN FuELs FOR ASIA: TEcHANcAL OPyyONS FOR AMOVING TowARDs Ums.ADFD GASOIUNE AND Low-SULFUR DiESsa 92
Table D.: Canada and U.S. Tier I Emission Standards (1994-)-Light Duty Vehiclesand Trucks
Vehicle GVWR Fuel LVW or ALVW Mileage NMHC CO NOx (glmi) PM (g/mi)(Ibs) (Ibs) (miles) (g/mi) (gimi)
Light-Duty all non-diesel all 50,000 0.25 3.4 0.4 0.08Vehicles all diesel all 5,000 0.25 3.4 1.0 0.08
all non-diesel all 100,000 0.31 4.2 0.60 0.10
all diesel all 100,000 0.31 4.2 1.25 0.10
Light-Duty 0 - 6,000 non-diesel 0 - 3,750 50,000 0.25 3.4 0.4 0.08
Trucks 0 - 6,000 diesel 0 - 3,750 50,000 0.25 3.4 1.0 0.08
0 - 6,000 non-diesel 3,751 - 5,750 50,000 0.32 3.4 0.7 0.08
0 -6,000 diesel 3,751- 5,750 50,000 0.32 3.4 0.7 0.08
0 - 6,000 non-diesel 0 - 3,750 100,000 0.31 4.2 0.60 0.10
0 -6,000 diesel 0 -3,750 100,000 0.31 4.2 1.25 0.10
0 -6,000 non-diesel 3,751 -5,750 100,000 0.40 5.5 0.97 0.10
0 -6,000 diesel 3,751 -5,750 100,000 0.40 5.5 0.97 0.10
Heavy >6,000 diesel >5,750 50,000
Light-Duty >6,000 non-diesel 3,751 -5,750 120,000 0.46 6.4 0.98 0.10Trucks>6,000 diesel 3,751 -5,750 120,000 0.46 6.4 0.98 0.10
>6,000 non-diesel >5,750 120,000 0.56 7.3 1.53 0.12
>6,000 diesel >5,750 120,000 0.56 7.3 1.53 0.12
Note: GVWR = gross vehicle weight registered; LVW loaded vehicle weight; ALVW axle loaded vehicle weight
Source: Based on information provided by the counties to Environment Canada, 1997.
Table D.2: U.S. Tier I Emission Standards (1994-)-Heavy duty Engines and UrbanBuses
Vehicle Fuel GVWR (Ibs) Mileage NMHC (glhp-hr) CO (g/hp-hr) NOx (glhp-hr) PM (glhp-hr)
Heavy non-diesel < 14,000 110,000 1.1 14.4 4.0DutyTrucks non-diesel >14,000 1.9 37.1 4.0 -
diesel urban buses 110,000 1.3 15.5 4.0 0.05
diesel trucks 1.3 15.5 4 0.1
Source: Based on informaton provided by the country to Environment Canada, 1997.
93 APPENDIX D
Table D.3: Exhaust Emissions, European Vehicles (1995 Representative Fleet)
Emission Regulations/Controls Carbon Hydrocarbons Nitrogen Carbon ParticulateMonoxide Oxides Dioxide Matter
ECE 15-03 31.5 3.57 2.29 188 --
ECE 15-04 24.1 2.97 2.4 192 -
Three-way catalytic converter 5.2 0.32 0.4 247 -
Diesel (included for comparsion) 0.7 0.13 1.22 188 0.14
- = Not applicable.
Source: Conservation of Clean Air and Water in Europe, 1995. "Motor Vehicle Emission Regulations and Fuel Specifications inEurope and the United States."
Table D.4: E. U. Light Duty Vehicle Emission Standards (1996-)
Vehicle GVWR (kgs) Fuel HC + NOx (glkm) CO (g/km) PM (g/lkm)
Light- all non-diesel 0.5 2.0
Duty all diesel 0.7 1.0 0.08Vehicles
all direct injection diesel 1.0 0.9 0.10
Light- 0 - 1,250 all 0.97 2.72 0.14
Trucks 1,251 -1,700 all 1.40 5.17 0.19
>1,700 all 1.70 6.90 0.25
Source: Based on information supplied by the countries to Environment Canada, 1997.
Table D. 5: E. U. Heavy Duty Diesel Vehicle Emission Standards (1993-2000)
Category Engine Power HC (g/kw-hr) CO (glkw-hr) NOx (glkw-hr) PM (glkw-hr)
Eurol 1993 <85 Kw 1.1 4.5 8.0 0.63
> 85 Kw 1.1 4.5 8.0 0.36
Euro 2 1996 all 1.1 4.0 7.0 0.15
Euro 3 2000 TBD TBD TBD
Source: Based on informaton provided by the countries to Environment Canada, 1997.
CLEANFUElsFORAStI: TECHNICAL OPnoxs FORAMOVING TowARDs UNLEADED GASOLINE AND LOW-S[FURDIESEL 94
Table D. 6: South Korea Vehicle Emission Standards (1996)
Vehicle GVWR (tons) Fuel HC (glkm) CO (glkm) NOx (glkm) PM (g/km)
Light-Duty Vehicles all diesel 0.25 2.11 0.62 0.08
Light-Duty Trucks < 2 diesel 0.5 6.21 1.43 0.31
HDE (g/kWh) all diesel 1.2 4.9 11.0 0.9
Source: Based on information supplied by the country to Environment Canada, 1997.
Table D. 7: Current Exhaust Emissions Standards Republic of Singapore
Type of Vehicle Emission Standard (for Registration) Implementation Date
Petrol-driven vehicles European Union Directive 91/441/EEC (Consolidated Emissions 1 July 94Directive) or the JIS 78 Emission Standard
Diesel-driven vehicles UN/ECE R 24.03 Black Smoke Emission Standard 1 January 91
Motorcycles & Scooters United States Code of Federal Regulations (US 40 CFR 86.410-80 1 October 91Emission Standard)
Source: Based on information supplied by the country to Environment Canada, 1997.
Table D. 8: Diesel Driven Exhaust Emissions StandardsRepublic of Singapore (effective July 1997)
Vehicle Type Emission Standard Applicable Implementation Date
Passenger Cars 93159/EEC 1 July 97
JIS 94 Standard 1 July 97 - 30 June 98
Light Commercial 93/59/EEC 1 July 97Vehicles JIS 93 Standard 1 July 97 - 30 June 98
Heavy Duty 91/542/EEC Stage 1 1 July 97
Vehicles JIS 94 Standard 1 July 97 - 30 June 98
Source: Based on information supplied by the country to EnvironmentCanada, t 997.
95 APPENDIXD
Table D. 9: Enmssion Standards for Japan
Motor Vehicle Category Permissible limits recommended for Target Values Measurement Mode(mean-Value)
CO HC NOx PM Smoke
Small and mini-sized 13.0 g/km 200 g/km 0.30 g/km - - ISO 6460 (attachedtwo-wheeled motor vehicles; With Measurement mode)Four- cycle engines
1st and 2nd class motor-driven 8.0 g/km 300 g/km 0.10 g/km - - ISO 6460 (attachedcycles with Two- cycle engines Measurement mode)
Gasoline-and LPG-fueled 6.50 g/km 0.25 g/km 0.25 glkm - - 10 15 Modemini-sized trucks (excludingthose with two-cycle engines)
Gasoline and 1.7t < 6.50 g/km 0.25 g/km - - - 10 * 15 ModeLPG-fueled, GVW <medium and 2.5theavy-duty motorvehicles (excludingpassenger vehicleswith seatingcapacity of less 2.5<GVW 51.0 g/kwh 180g/kwh - - - Gasoline 13 Modethan 11)
Diesel-powered heavy-duty - - 4.50 g/kwh 0.25 g/kwh 25% Diesel 13 Modevehicles, with 12t < GVW
Source: Based on information supplied by the country to Environment Canada, 1997.
CLEAN FuEIs FOR ASIA. TECHNicAL OPI70AS FOR MOVING TowARDs UNLEADED GASOLINE AND Low-SULFUR DIESEL 96
Table D. 10: Hong Kong New Vehicle Emisssion Standards (as of I April 1995) (pt. 1)
Class of Vehicle Politive Ignition Engine Compression Ignition Engine
Test Procedure Limits Test Procedure Limits
All 72/306/EEC Free Acceleraton K-1.20Smoke as amended by 89/491/EEC(light absorption coefficient K, m-i)
Private Car / Taxi US FTP 75 (g/km) HC - 0.26 US FTP 75 (g/km) HC - 0.26
CO -2.10 CO - 2.10
NOx-0.63 NOx-0.63
PM - 0.12
Japan 10.15 mode (g/km) HC - 0.39 Japan 10.15 mode (g/km) HC - 0.62
CO - 2.70 CO - 2.70
NOx-0.48 VW < = 1.265 tonne NOx-0.72
VW>1.265 tonne NOx-0.84
PM-0.34
93/59/EEC Type 1 (g/km) HC+NOx-0.97 93/59/EEC Type 1 (g/km) HC+NOx-0.97
CO-2.72 CO-2.72
PM-0.14
maximum mass exceeds 2,500 tonne OR designed to carry more than 6 occupants including driver
RW <=1.250 tonne HC+NOx-0.97 RW < = 1.250 tonne HC+NOx-0.97
CO - 2.72 CO- 2.72
PM- 0.14
1.250 tonne < RW < + 1.700 tonne HC+NOx-1.4 1.250 tonne < RW < =1.700 tonne HC+NOx-1.4
CO-5.17 CO- 5.17
PM-0.19
RW > 1.700 tonne HC+NOx - 1.7 RW > 1.700 tonne HC+NOx 1.7
CO - 6.9 CO - 6.9
PM-0.25
Source: Based on information supplied by the jurisdiction to Environment Canada, 1997.
97 APPENIxD
Table D. 10: Hong Kong New Vehicle Emisssion Standards (as of ) April 1995) (pt 2)
Class of Vehicle PolWve IgnlUon Engine Compression Igntlion Engine
Test Procedure Limits Test Procedure Limits
Light Goods Vehicle US FTP 75 (g/km) HC - 0.50 US FTP 75 (g/km) HC - 0.50I Light Bus / with ~CDW not more than CO -6.20 CO - 6.201.7 tonne NOx-0.75 NOx-0.75
PM - 0.16
Japan 10.15 mode (g/km) HC - 0.39 Japan 10.15 mode (g/km) HC - 0.62
CO - 2.70 CO - 2.70
NOx-0,48 NOx-0.84
PM -0.34
93/59/EEC Type I (g/km) 93159/EEC Type 1 (g/km)
RW < + 1.250 tonne HC+NOx-0.97 RW < = 1.250 tonne HC+NOx-0.97
CO - 2.72 CO - 2.72
1.250 tonne < RW < = 1.700 tonne HC+NOx- 1.4 PM - 0.14
CO - 5.17 1.250 tonne < RW < 1.700 HC+NOx- 1.4tonne
CO - 5.17
PM - 0.19
Light Goods Vehicle US FTP 75 (g/km) HC - 0.50 US FTP 75 (g/km) HC - 0.50/ Light Bus / withDW more than 1.7 C0- 6.20 CO -6.20tonne but not more NOx-l.10 NOx-l.10than 2.5 tonne
PM - 0.28
Japan 10.15 mode (g/km) HC - 2.70 Japan 10.15 mode (g/km) HC - 0.62
CO - 17.0 CO -2.70
NOx-0.98 NOx-1.82
PM - 0.43
93/59/EEC Type 1 (g/km) 93/59/EEC Type 1 (g/km)
RW < = 1.250 tonne HC+NOx- 0.97 RW. < = 1.250 tonne HC+NOx-0.97
CO - 272 C0- 2.72
1.250 tonne < RW < = 1.700 tonne HC+NOx- 1.4 PM-0.14
C0- 5.17 1.250 tonne < RW < = 1.700 HC+NOx-1.4tonne
RW > 1.700 tonne HC+NOx - 1.7 CO - 5.17
CO - 6.9 PM - 0.19
RW > 1.700 tonne HC+NOx -1.7
CO - 6.9
Source: Based on information supplied by the jurisdiction to Environment Canada, 1997.
CLEAN FuEs FOR AsI: TECHNMCAL OPyONs FOR MOVING TOwARDs UNSEADFD GAsoLMNE SD Low-SULFUR DIESEL 98
Table D. 10: Hong Kong New Vehicle Emisssion Standards (as of I April 1995) (pt 3)
Class of Vehicle Politive Ignition Engine Compression Ignition Engine
Test Procedure Limits Test Procedure Limits
Light Goods US FTP 75 (glkm) HC - 0.50 US FTP 75 (glkm) HC - 0.50Vehicle I Light Bus/ with DW more CO - 6.20 CO - 6.20than 2.5 tonne butnot more than 3.5 NOx1.i10 NOx-1i10tonne PM -0.28
Japan HDP 13 mode (g/kwh) HC - 7.90 93159/EEC Type 1 (glkm)
CO - 136 RW < = 1.250 tonne HC+NOx-0.97
NOx-7.20 CO - 2.72
93/59/EEC Type 1 (g/km) PM - 0.14
RW < = 1.250 tonne HC+NOx - 0.97 1.250 tonne < RW < = 1.700 tonne HC+NOx-1.4
CO - 2.72 CO -5.17
1.250 tonne < RW < = 1.700 HC+NOx-1.4 PM - 0.19tonne
CO - 5.17 RW > 1.700 tonne HC+NOx-1.7
RW > 1.700 tonne HC+NOx- 1.7 CO - 6.9
CO - 6.9 PM - 0.25
Goods Vehicle I US HDO Transient (glkwh) HC - 2.55 US HDD Transient (g/Kwh) HC - 1.74Light Bus I Bus /wAth DW more than CO -49.7 CO -20.83.5 tonne NOx -6.70 NOx-8.04
PM -0.80
Japan HDP 13 mode (g/kwh) HC - 7.90 91/542/EEC (glkwh) HC - 1.1
CO - 136 CO - 4.5
NOx-7.20 NOx- 8.0
Engine Power < = 85 kw PM - 0.61
Engine Power > 85 kw PM - 0.36
FTP -Federal Test Procedure DW - Design Weight RW - Reference Mass
HDP -Heavy Duty Petrol (Gasoline) HDO-Heavy Duty Otto HDD-Heavy Duty Diesel
Source: Based on information supplied by the jurisdiction to Environment Canada, 1997.
99 APPENDIX D
Table D.ll: Hong Kong Automotive Fuel Specifications
Diesel Properties 1 April 1995 1 April 1997 TestMethod
Sulphur (% by Wt.) .20 Maximum 0.05 Maximum ASTM D4294
Cetane Number 50 Minimum 50 Minimum ASTM D613
Viscosity (mm21s) 2.0-4.5 2.0-4.5 ASTM D445
Distillation (C) ASTM D86
IBP Report Report
10 % Volume Report Report
50 % Volume Report Report
90 % Volume 357 Maximum Report
95% Volume 370 Maximum
Density (kg/I) .820-.860 .820-.860 ASTM D1298
Unleaded Petrol Properties 1 April 1995 1 April 1997 Test Method
Lead (g/L) .013 Maximum .005 Maximum ASTM D3237
Sulphur (% Mass) .10 Maximum .050 Maximum ASTM D1266
Motor Octane Number 85.0 Minimum 85.0 Minimum ASTM D2700
Research Octane Number 95.0 Minimum 95.0 Minimum ASTM D2699
Benzene (% Vol) 5 % Max.(voluntary) 5 % Maximum ASTM D4420
Methanol (% Vol) (a) 3 % Maximun ASTM D5599
Ethanol (% Vol) (a) 5 % Maximum ASTM D5599
Iso-propyl alcohol (% Vol) (a) 5 % Maximum ASTM D5599
Tertiary butyl alcohol (% Vol) (a) 7 % Maximum ASTM D5599
Iso-butyl alcohol (% Vol) (a) 7 % Maximum ASTM D5599
Ethers containing 5 or more carbon atoms per molecule (% Vol) 10 % Maximun ASTM D5599(a)
Other organic oxygenates (% Vol) (a) 7 % Maximum ASTM D5599
Mixture of all organic oxygenates
Source: Based on information supplied by the jurisdiction to Environment Canada, 1997.
Cz.Ai FuELs FOR AmiA: TECHMCAL OFfloNs FOR MOVIPNG TowARDs UNLEiADHD GASOIINE AND Low-SUz.PUR DIESFL 100
Table D. 12: Malaysia Gasoline Vehicle Emissions Standards
Emissions Standard Effective Date
ECE R 24.03 (for all diesel vehicles) September 1, 1996
ECE R 49 (for heavy-duty vehicles having GVW > September 1, 19973.5 tons)
ECE R 15.04 (for vehicles having GVW <3.5 tons) September 1, 1997
93/59/EEC (for vehicles having GVW up to 3.5 tons) January 1, 1997 (new models)
ECE R 49-02 (Euro 1) (for having duty vehicles January 1, 1997 (new models)having GVW up to 3.5 tons)
Source: Based on information provided by the country to Environment Canada, 1997.
Table D. 13: Malaysia Diesel Vehicle Emissions Standards
Emissions Standard Effective Date
ECE R 15-04 (for vehicles having GVW <3.5 tons) November 1, 1996
91/441/EEC (for vehicles having GVW >2.5 tons) January 1, 1997 (new models)
93/59/EEC (for vehicles having GVW <3.5 tons) January 1, 1997 (new models)
94/12/EC (for vehicles having GVW up to 2.5 tons) January 1, 1997 (new models)
GVW = gross vehicle weight
Source: Based on information supplied by the country to Environment Canada, 1997.
Table D. 14: International Vehicle Exhaust Emission Regulations--Automobiles
New Automobiles Used Automobiles
Country Yr. of Reg. Lead (gl) HC (ppm) N02 (glkm) CO (%) Yr. of Reg. Lead (g/L) HC (ppm) N02 (glkm) CO (%)
Anguilla No Regulations
Argentina 1995 N/A Jan.96-400 '96-1.4 Jan.95-2.5 1995 N/A '83-91-900 N/D '83-91-4.5
Jan.97-250 '97-0.6 Jan.97-05 '92-92-600 '92-92-3.0
Jan.99-250 '99-0.6 Jan.99-0.5 '95-400 '95-2.5
Barbados No Regulatons
Bermuda No Regulations
Bolivia 1995 N/A 200 1.13-1.90 2.0 1995 N/A 400-700 1.13-1.90 3.0-6.0
Brazil 1992 N/A '92-1.2 g/km '92-1.4 '92-12 g/km N/A N/A N/A N/A N/A
'97-0.3 g/km '97-0.6 '97-2.0 g/km
Chile 1991 N/A 0.25 g/km 0.62 2.11 g/km 1994 N/A 500-800 - 3.5-4.5
Columbia 1996 N/A 0.25 g/km 0.62 2.10 g/km 1996 N/A 750 - 4.5
Costa Rica 1996 N/A 350 800 ppm 2.0 1995 N/A No limits No limits 4.5
Dominican Republic No regulations
El Salvador There is a law controlling emissions, but there are no regulations
Hait No regulatons
Honduras 1999 N/A 126 0.5 1,998 N/A 601 - 5.5
Jamaica No Regulations
Netherlands Antiles No ReguationsNicaragua 1997 0.013 125 - 0.5 1997 0.013 800 - 4.5
Paraguay No Regulatons
Peru No Regulations, except for CO limits for one historical area in Lima
Trinidad & Tobago No Regulatons
Uruguay No Regulations
N/A=Not Applicable N/D=No DataSource: Based on information supplied by the countries to Environment Canada, 1997.
Table D.15: International Vehicle Exhaust Emission Regulations-Light-Duty Trucks
New Light Duty Trucks Used Light Duty Trucks
Country Yr.of Reg. Lead (g/L) HC (ppm) N02 (glkm) CO (%/) Yr. of Reg. Lead (glL) HC (ppm) N02 (g/km) CO(%)
Anguilla No RegulationsArgentna 1995 N/A Jan.95-400 '95-2.5 Jan.95-2.5 1995 '83-91-900 N/D '83-91-4.5
Jan.97-250 '97-06 Jan.97-0.5 '92-92-600 '92-92-3.0
Jan.99-260 '99-0.6 Jan.99-0.5 N/A '95-400 '95-2.5
Barbados No Regulations 0
Bermuda No RegulationsBolivia 1995 N/A 200 1.13-2.57 2.0 1995 N/A 400-700 1.13-2.57 3.0-6.0
Brazil 1994 '96-0.4 gikwh '94-2.45g//kwh '94-14.4g/kwh '94-11.2gikwh N/A N/A N/A N/A NSA'00-0.15g/kwh '96-1 .23g/kwh '96-9.Og/kwh '96-4.9g/kwh N
'00-1.10g/kwh '00-7.0g/kwh '00-4.0g/kwh 0
Chile 1991 N/A 0.5g/km 1.43g/km 6.2g/km 1994 N/A 500-800 - 3.5-4.5
Columbia 1996 N/A 1.05g/km 1.43g/km 11.5g/km 1996 N/A 750 - 4.5
Costa Rica 1995 N/A 350 800g/km 2.0 1995 N/A No Limits No Limits 4.5
Dominican No RegulationsRepublicEl Salvador There is a law controlling emissions, but there are no regulations 0
Haiti No RegulationsHonduras - N/A - - - - N/A - - -
Jamaica No RegulationsNicaragua - N/A - - - - N/A - - -
Paraguay No RegulationsPeru No Regulations, except for CO limits for one historical area in Lima
Trinidad & Tobago No Regulations
Uruguay No Reaulations
N/A=Not Applicable N/D=No Data
Source: Based on information supplied by the countries to Environment Canada, 1997.
Table D.16. International Vehicle Exhaust Emission Regulations--Heavy-Duty Trucks
New Heavy Duty Trucks Used Heavy Duty Trucks
Country Yr. of Reg. Lead (g/L) HC (ppm) N02 (glkm) CO (%/) Yr. of REG. Lead (gIL) HC (ppm) N02 1gkm) CO (%/)
Anguilla No Regulations
Argentina 1995 Jan.95-600 Jan.95-14.4 Jan.95-3.0 1995 Jan.95-600 N/D Jan.97-3.0
Jan.97-400 Jan.97-2.5 Jan.97-2.5 Jan.97-400 Jan.95-2.5
Barbados No Regulations
Bermuda No Regulations
Bolivia 1996 - 200 4.50 2.0 1995 - 400-700 4.5 3.0-6.0
Brazil 1994 '96-0.4g/kwh '94-2.45g/kwh '94-14.4g/kwh '94-11.2g/kwh N/A N/A N/A N/A N/A
'00-0.15g/kwh '96-1 .23g/kwh '96-9.Og/kwh '96-4.9g/kwh
'00-1. 1Og/kwh '00-7Og/kwh '00-4.Og/kwh
Chile
Columbia 1996 N/A 10.Og/km lO.Og/km 25.0g/km 1996 N/A 750 - 4.5
Costa Rica 1995 N/A 350 800ppm 2.0 1995 N/A No limits No limits 4.5
Dominican No RegulatonsRepublic
El Salvador There is a law controlling emissions but there are no regulatonsHaiti No Regulations
Honduras - N/A - - - - N/A
Jamaica No Regulations
Nicaragua - N/A - - - - N/A - -
Paraguay No Regulations
Peru No Regulabons, except for CO limits for one historical area in Lima
Trinidad & No RegulationsTobago
Uruguay No Regulations
N/A=Not Applicable N/D=No Data
Source: Based on information provided by the countries to Environment Canada, 1997
Table D. 17. Lead Added to Gasoline (1990-2000)
Actual Additions (Tons of PbNear) Planned Additions (Tons of PbIYeait Last Year Leaded oCountry 1990 1993 1995 1996 1998 2000 Gasoline Available
45 60 0 0 0 0 1996Argentne Eg3 1490 960 34 0 0 0 1996
Refisan Est.100 Est.100 0 0 0 0 1996
YPF(1 Ref.) 400 290 0 0 0 0 1996Barbados Est.125 116 107 127 Est.75 EST.25 2000Bolivia 19.8 23.3 0 0 0 0 1995Brazil 0 0 0 0 0 0 1992
Chile(1 Ref) 310 290 250 Est.250 Est.200 Est.200 N/RColumbia Est.0 0 0 0 0 0 1990
Costa Rica 71 86 57 12.6 0 0 1996 0438 Est. 431 452 400 Est.375 Est.350 no date
Dominican Republic 2400 1466 1328 569 0 0 2000
El Salvador 138 225 202 84 0 0 1996Guatemala Est.140 0 0 0 0 0 1991
Honduras Est.125 0 0 0 0 0 Ref. S/D in 1992Jamaica 2700 1022 1217 973 486 243 no dateMexico 8957 2293 1501 924 512 0 1999
Netherlands 0
Antilles Est.2500 Est.2200 Est.1800 Est.1 400 Est.1000 Est.600 No DateEst.150 Est.150 Est.150 Est.90 0 0 1996
Panama Est.500 Est.500 Est.500 Est.500 Est.500 Est.500 -Paraguay 93.6 67.2 86.1 187.6 Est.80 Est.80 No DatePeru 1500 1450 1413 1149 1134 1159 No Date
Trinidad &Tobago Est.75 46 23 23 8 8 2000Uruguay 380 406 410 410 410 410 No DateVenezuela 4783 4221 3637 3160 2870 2853 2007
TOTALS 27440 16403 13167 10259 7650 6428
No. of countries contributing to total 20 18 17 16 12 11% of 1990 value 100 59.8 48.0 37.4 27.8 23.4
No. of countries contrihu ina to total 20 18 17 16 12 11
N/D = No data Est. = Estmate by AlconsultSource: Based on information provided by the countries to Environment Canada, 1997.
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Fax: (353 1) 475-2670 URL: hnp Ilntnentmx E-mail. books%[email protected] compi E-mail LHLWsd.lanka.netURL. hnp:/lwww ipscg.wawpVipsexponr 0' ' 9
RECENT WORLD BANK TECHNICAL PAPERS (continued)
No. 336 Francis, with Akinwumi, Ngwu, Nkom, Odihi, Olomajeye, Okunmadewa, and Shehu, State, Community, and LocalDevelopment in Nigeria
No. 337 Kerf and Smith, Privatizing Africa's Infrastructure: Prormise and Change
No. 338 Young, Measutring Economic Benefitsfor Water Investments and Policies
No. 339 Andrews and Rashid, The Financing of Pension Systems in Central and Eastern Europe: An Overview of Major Trends andTheir Determinants, 1990-1993
No. 340 Rutkowski, Changes in the Wage Structure durinig Econtomic Transition in Central and Easternl Europe
No. 341 Goldstein, Preker, Adeyi, and Chellaraj, Trends in Health Status, Services, and Finanace: The Transition in Central andEastern Europe, Volume I
No. 342 Webster and Fidler, editors, Le secteur informtiel et lcs institutionis de microfinianicement en Afrique de l'Ounest
No. 343 Kottelat and Whitten, Freshwater Biodiversity in Asia, with Special Referenice to Fish
No. 344 Klugman and Schieber with H[eleniak and Hon, A Suirvey of Health Reform in Cenitral Asia
No. 345 Industry and Mining Division, Industry and Energy Department, A Mining Strategyfor Latin America and the Caribbean
No. 346 Psacharopoulos and Nguyen, The Role of Government and the Private Sector inZ Fightinzg Poverty
No. 347 Stock and de Veen, Expandinig Labor-based Methods for Road Works in Africa
No. 348 Goldstein, Preker, Adevi, and Chellaraj, Trends in Hlealth Status, Services, and Finanice: The Transition in Central andEastern Europe, Volume II, Statistical Annex
No. 349 Cummings, Dinar, and Olson, Nezw Evaluation Proceduiresfor a New Generation of Water-Related Projects
No. 350 Buscaglia and Dakolias, Judicial Reform in Latin American Courts: The Experience in Argentina and Ecuador
No. 351 Psacharopoulos, Morley, Fiszbein, Lee, and Wood, Poverty and Inconme Distributioni in Latin America: The Story of the1980s
No. 352 Allison and Ringold, Labor Markets in Transition in Central and Eastern Euirope, 1989-1995
No. 353 Ingco, Mitchell, and McCalla, Global Food Suipply Prospects, A Background Paper Prepared for the World Food Sunmnit,Rome, November 1996
No. 354 Subramanian, Jagannathan, an-d Meinzen-Dick, User Organizationsfor Sustainable Water Services
No. 355 Lambert, Srivastava, and Vietmeyer, Medicinal Plants: Rescuing a Global Heritage
No. 356 Aryeetey, Hettige, Nissanke, and Steel, Financial Market Fragmentation and Reforms in Sub-Saharan Africa
No. 357 Adamolekun, de Lusignan, and Atomate, editors, Civil Service Reform in Francophone Africa: Proceedings of a WorkshopAbidjan, January 23-26, 1996
No. 358 Ayres, Busia, Dinar, Hirji, Lintner, McCalla, and Robelus, Integrated Lake and Reservoir Management: World BankApproach and Experience
No. 360 Salman, The Legal Frameworkfor Water Users' Associations: A Comparative Study
No. 361 Laporte and Ringold. Trends in Education Access and Financing during the Transition in Central and Eastern Europe.
No. 362 Foley, Floor, Madon, Lawali, Montagne, and Tounao, The Niger Household Energy Project: Promoting Rural FuelwoodMarkets and Village Management of Natural Woodlands
No. 364 Josling, Agricultuiral Trade Policies in the Andean Group: Issues and Options
No. 365 Pratt, Le Gall, and de Haan, Investing in Pastoralismn: SustainTable Natutral Resource Use in Arid Africa and the Middle East
No. 366 Carvalho and White, Combining the Quantitative and Qualitative Approaches to Poverty Measurement and Analysis:The Practice and the Potential
No. 367 Colletta and Reinhold, Reviezw of Early Childhood Policy and Programs in Sub-Saharan Africa
No. 368 Pohl, Anderson, Claessens, and Djankov, Privatization and Restructuring in Central and Eastern Europe: Evidenceand Policy Options
No. 370 Dejene, Shishira, Yanda, and johnsen, Land Degradation in Tanzania: Perception from the Village
No. 371 Essama-Nssah, Analyse d'une repartition du niveain de vie
No. 373 Onursal and Gautam, Vehicular Air Pollution: Experiencesfrom Seven Latin American Urban Centers
No. 374 Jones, Sector Investment Programs in Africa: Issues and Experiences
No. 375 Francis, Milimo, Njobvo, and Tembo, Listening to Farmers: Participatory Assessment of Policy Reform in Zambia'sAgriculture Sector
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