Chapter 12 Chapter 12 AirAir

ObjectivesObjectives

NameName five primary air pollutants, five primary air pollutants, and give sources for each.and give sources for each.

NameName the two major sources of air the two major sources of air pollution in urban areas.pollution in urban areas.

DescribeDescribe the way in which smog the way in which smog forms.forms.

ExplainExplain the way in which a thermal the way in which a thermal inversion traps air pollution.inversion traps air pollution.

I. What Causes Air Pollution?I. What Causes Air Pollution?

Air pollutionAir pollution – when harmful – when harmful substances build up in the air to substances build up in the air to unhealthy levelsunhealthy levels can be in the form of solids, liquids, or can be in the form of solids, liquids, or

gasesgases Most is a result of human activities, Most is a result of human activities,

but pollutants can also come from but pollutants can also come from natural sourcesnatural sources natural pollutants include volcanic natural pollutants include volcanic

eruptions, dust, pollen, and sporeseruptions, dust, pollen, and spores

A. Primary and Secondary A. Primary and Secondary PollutantsPollutants Primary pollutantPrimary pollutant – a pollutant – a pollutant

that is put directly into the air by that is put directly into the air by human activityhuman activity

-soot from smoke-soot from smoke -sources – electricity production, -sources – electricity production,

industry, transportation, and other industry, transportation, and other sourcessources

Secondary pollutantSecondary pollutant – forms when a – forms when a primary pollutant comes into contact primary pollutant comes into contact with other primary pollutant or other with other primary pollutant or other naturals substances such as water naturals substances such as water vapor and sunlight, and a chemical vapor and sunlight, and a chemical reaction takes placereaction takes place

ground level ozone – forms when ground level ozone – forms when emissions from cars, trucks, and emissions from cars, trucks, and natural sources react with the natural sources react with the ultraviolet rays of the sun and them ultraviolet rays of the sun and them mix with the oxygen in the mix with the oxygen in the atmosphereatmosphere

SmogSmog

B. The History of Air PollutionB. The History of Air Pollution Not a new thing – whenever Not a new thing – whenever

something burns, pollutants enter the something burns, pollutants enter the airair

Roman philosopher, Seneca, Roman philosopher, Seneca, complained about foul air in Romecomplained about foul air in Rome

1273, England’s King Edward I 1273, England’s King Edward I ordered that burning a particularly ordered that burning a particularly dirty kind of coal, “sea coal” was dirty kind of coal, “sea coal” was illegalillegal

-one was even hanged for -one was even hanged for disobeyingdisobeying

Soot had to be cleaned by Soot had to be cleaned by handhand

Orphans or poor children from work Orphans or poor children from work houses were purchased and used to houses were purchased and used to climb into the chimneys to clean them climb into the chimneys to clean them

Children were often reluctant to climb to Children were often reluctant to climb to the top of chimneys, so small fires were the top of chimneys, so small fires were lit to encourage them to climb to the top.lit to encourage them to climb to the top.

Hence the expression, “light a fire under Hence the expression, “light a fire under them”them”

Sweeps were often starved so they could fit in Sweeps were often starved so they could fit in the narrow passages at an older agethe narrow passages at an older age

Problem is much worse today because Problem is much worse today because modern industrialized societies burn modern industrialized societies burn large amounts of fossil fuelslarge amounts of fossil fuels

-in urban areas, most pollution comes -in urban areas, most pollution comes from from vehicles and industryvehicles and industry

Table of Primary Air PollutantsTable of Primary Air Pollutants Sources of Air PollutantsSources of Air Pollutants1.1. Carbon monoxide CO – canary in a coal mineCarbon monoxide CO – canary in a coal mine

2.2. Nitrogen (Nitrous) oxides NO Nitrogen (Nitrous) oxides NO x x brownish hazebrownish haze

3.3. Sulfur dioxide SOSulfur dioxide SO22

4.4. Volatile Organic Compounds VOC’s - gasoline, Volatile Organic Compounds VOC’s - gasoline, benzene, toluene, and xylenebenzene, toluene, and xylene

5.5. Particulates - smoke, ash, soot, dust, lead -From Particulates - smoke, ash, soot, dust, lead -From industrial processes, cars, construction, agricultureindustrial processes, cars, construction, agriculture

C. Motor Vehicle EmissionsC. Motor Vehicle Emissions Almost 1/3 (33%) of our air pollution comes from Almost 1/3 (33%) of our air pollution comes from

gasoline burned by vehiclesgasoline burned by vehicles Air combustion engine > SO2 + NO x + CO + Air combustion engine > SO2 + NO x + CO +

H2OH2O Controlling Vehicle EmissionsControlling Vehicle Emissions

-Clean Air Act passed in 1970 and strengthened in -Clean Air Act passed in 1970 and strengthened in 1990 gives the Environmental Protection Agency 1990 gives the Environmental Protection Agency (EPA), the authority to regulate vehicle emissions in (EPA), the authority to regulate vehicle emissions in the USthe US

-Required the gradual elimination of lead in gasoline – -Required the gradual elimination of lead in gasoline – as a result lead pollution decreased by more than 90%as a result lead pollution decreased by more than 90%

-catalytic converters – required in automobiles, clean -catalytic converters – required in automobiles, clean exhaust gases of pollutants before they can exit the exhaust gases of pollutants before they can exit the tailpipetailpipe

CAFÉ StandardsCAFÉ Standards CAFÉ Standards – Corporate Average Fuel CAFÉ Standards – Corporate Average Fuel

Economy – mandated by the government Economy – mandated by the government that automobiles have a certain fuel that automobiles have a certain fuel efficiencyefficiency

-caused fuel efficiency to rise between 1973 -caused fuel efficiency to rise between 1973 and 85 but it has decreased from 88-2006and 85 but it has decreased from 88-2006

-no new increase in CAFÉ standards – so -no new increase in CAFÉ standards – so people people began buying gas-guzzling began buying gas-guzzling trucks and SUVs trucks and SUVs that do not meet that do not meet mileage standards that cars mileage standards that cars do do

Cash For Clunkers 2009 effort to remove Cash For Clunkers 2009 effort to remove SUVs and gas guzzlersSUVs and gas guzzlers

California Zero-Emission California Zero-Emission Vehicle ProgramVehicle Program

-in 1990 California Air Resources -in 1990 California Air Resources Board established the zero emission Board established the zero emission vehicle (ZEV) programvehicle (ZEV) program

zero-emission vehicleszero-emission vehicles are are vehicles that have no tailpipe vehicles that have no tailpipe emissions, no emissions from emissions, no emissions from gasoline, and no emission-control gasoline, and no emission-control systems that deteriorate over timesystems that deteriorate over time

ZEVZEV

by 2016, 16% of all vehicles sold in by 2016, 16% of all vehicles sold in California are required to be zero-California are required to be zero-emission vehiclesemission vehicles

-includes SUVs, cars, trucks, small vans-includes SUVs, cars, trucks, small vans -vehicles include electric cars and -vehicles include electric cars and

hydrogen carshydrogen cars -ZEV programs have also been adopted -ZEV programs have also been adopted

by Maine, Massachusetts, New York, by Maine, Massachusetts, New York, and Vermontand Vermont

BTW….BTW….

According to the U.S. Department of According to the U.S. Department of Transportation, Americans drove Transportation, Americans drove their vehicles over their vehicles over 2.6 trillion2.6 trillion miles miles in 1998.in 1998.

Over 90 percent of that mileage was Over 90 percent of that mileage was driven by passenger vehicles. The driven by passenger vehicles. The rest was driven by trucks and buses.rest was driven by trucks and buses.

D. Industrial Air PollutionD. Industrial Air Pollution -Many industries and power plants that -Many industries and power plants that

generate our electricity must burn fuel to generate our electricity must burn fuel to get the energy they need.get the energy they need.

-Usually burn fossil fuels – this releases -Usually burn fossil fuels – this releases large amounts of sulfur dioxide and large amounts of sulfur dioxide and nitrogen oxide into the air.nitrogen oxide into the air.

-Power plants that produce electricity -Power plants that produce electricity emit at least 2/3 of all sulfur dioxide and emit at least 2/3 of all sulfur dioxide and 1/3 of all nitrogen oxides 1/3 of all nitrogen oxides

VOCs – chemical VOCs – chemical compounds that form toxic compounds that form toxic

fumesfumes Some industries also produce VOCs -When Some industries also produce VOCs -When

people use a product that contains VOCs, people use a product that contains VOCs, more VOCs are added to the airmore VOCs are added to the air

Regulating Air Pollution from IndustryRegulating Air Pollution from Industry -Clean Air Act requires many industries to use -Clean Air Act requires many industries to use

scrubbers or other pollution-control devicesscrubbers or other pollution-control devices ScrubberScrubber – a machine that moves gases – a machine that moves gases

through a spray of water that dissolves many through a spray of water that dissolves many pollutantspollutants Electrostatic PrecipitatorsElectrostatic Precipitators – machines used in – machines used in

cement factories and coal-burning power plants to cement factories and coal-burning power plants to remove dust particles from smokestacksremove dust particles from smokestacks

-remove about 22 million metric tons of ash -remove about 22 million metric tons of ash generated by coal burning power plants each yeargenerated by coal burning power plants each year

Thermal Inversion & Thermal Inversion & SMOGSMOG

SmogSmog – when air pollution hangs – when air pollution hangs over urban areas and reduces over urban areas and reduces visibilityvisibility

-results from chemical reactions that -results from chemical reactions that involve sunlight, air, car exhaust, involve sunlight, air, car exhaust, and ozoneand ozone

-pollutants released by vehicles and -pollutants released by vehicles and industries are the main causes of industries are the main causes of smogsmog

Temperature InversionsTemperature Inversions

-the circulation of air in the atmosphere -the circulation of air in the atmosphere usually keeps air pollution from reaching usually keeps air pollution from reaching dangerous levelsdangerous levels

-during the day, the sun heats the surface -during the day, the sun heats the surface of the earth and the air at the surface, the of the earth and the air at the surface, the warm air rises through the cooler air warm air rises through the cooler air above and carries pollutants away from above and carries pollutants away from the ground and into the atmospherethe ground and into the atmosphere

-sometimes pollution is trapped near the -sometimes pollution is trapped near the Earth’s surface by a temperature Earth’s surface by a temperature inversioninversion

The Air in LAThe Air in LA

Temperature inversionTemperature inversion – when the – when the air above is warmer than the air belowair above is warmer than the air below

-the warmer air keeps the cooler air at -the warmer air keeps the cooler air at the surface from moving upward so the surface from moving upward so pollutants are trapped below with the pollutants are trapped below with the cooler aircooler air

-if a city is located in a valley, the city -if a city is located in a valley, the city has a greater chance of experiencing has a greater chance of experiencing temperature inversions temperature inversions

-Los Angeles-Los Angeles

II. Air, Noise, and Light II. Air, Noise, and Light PollutionPollution

Air pollution can cause serious Air pollution can cause serious health problems particularly to those health problems particularly to those very young or old, or those with very young or old, or those with heart or lung problemsheart or lung problems

Air pollution is linked to disease – Air pollution is linked to disease – making existing diseases worsemaking existing diseases worse

A. Short-Term Effects of Air A. Short-Term Effects of Air Pollution of HealthPollution of Health

-many effects are short-term and reversible -many effects are short-term and reversible if the person’s exposure to the air pollution if the person’s exposure to the air pollution decreasesdecreases

-effects include headache, nausea, irritation -effects include headache, nausea, irritation to the eyes, nose, and throat, tightness in to the eyes, nose, and throat, tightness in the chest, coughing, upper respiratory the chest, coughing, upper respiratory infections (bronchitis and pneumonia)infections (bronchitis and pneumonia)

-make the condition worse of individuals -make the condition worse of individuals who suffer from asthma and emphysema who suffer from asthma and emphysema worseworse

B. Long-Term Effects of Air B. Long-Term Effects of Air PollutionPollution

-long term effects include -long term effects include emphysema, lung cancer, heart emphysema, lung cancer, heart diseasedisease

-worsen medical conditions suffered -worsen medical conditions suffered by older peopleby older people

-damage the lungs of children-damage the lungs of children

C. Indoor Air PollutionC. Indoor Air Pollution

The quality of air inside a home or The quality of air inside a home or building is sometimes worse than the building is sometimes worse than the quality of air outsidequality of air outside

-less air circulation-less air circulation -plastics and other industrial chemicals -plastics and other industrial chemicals

are major sources of pollutionare major sources of pollution -found in carpets, building materials, -found in carpets, building materials,

paints, and furniture – particularly paints, and furniture – particularly when they are newwhen they are new

Every year billions of Every year billions of dollars are spent in dollars are spent in health costs to treat health costs to treat respiratory diseases respiratory diseases attributed to air attributed to air pollutionpollution

Persistent inflammation Persistent inflammation of bronchial liningsof bronchial linings

Constant coughing Constant coughing weakens bronchial weakens bronchial tubestubes

Bronchial passages Bronchial passages constrict and become constrict and become blocked with mucusblocked with mucus

(smokers know this)(smokers know this)

Air sacs lose their Air sacs lose their elasticity and can no elasticity and can no longer push air out longer push air out of lungsof lungs

Shortness of breathShortness of breath

Cigarette smoking main Cigarette smoking main cause, but…cause, but…

Non-smoking city dweller is Non-smoking city dweller is 4x more likely to get lung 4x more likely to get lung cancer than his rural cancer than his rural counterpart (because of air counterpart (because of air pollution)pollution)

In fact, in some cities, In fact, in some cities, just breathing the air is just breathing the air is the same as smoking 1-the same as smoking 1-2 packs of cigarettes a 2 packs of cigarettes a dayday

Mexico CityMexico City

Sick-building syndromeSick-building syndrome

Sick-building syndromeSick-building syndrome – buildings – buildings that have very poor air qualitythat have very poor air quality

-most common on hot places where -most common on hot places where buildings are tightly sealed to keep out buildings are tightly sealed to keep out the heatthe heat Like in CA and NMLike in CA and NM

-identifying and removing sources of -identifying and removing sources of indoor air pollution as well as ventilation indoor air pollution as well as ventilation is necessary for good air qualityis necessary for good air quality

activities such as renovating or painting activities such as renovating or painting can increase indoor air pollution and so can increase indoor air pollution and so ventilation should be increasedventilation should be increased

Using environmentally-friendly Using environmentally-friendly materials can minimize indoor air materials can minimize indoor air pollutionpollution

Developing countries have many Developing countries have many illnesses related to indoor air pollution illnesses related to indoor air pollution because of the wood-burning fireplaces because of the wood-burning fireplaces in the home with no ventilation to carry in the home with no ventilation to carry out the smokeout the smoke

-affect mostly women and children -affect mostly women and children

RadonRadon Radon gas is colorless, tasteless, and Radon gas is colorless, tasteless, and

odorless – it is also radioactiveodorless – it is also radioactive

-one of the gases produced by the -one of the gases produced by the decay of uranium – a radioactive decay of uranium – a radioactive element that occurs naturally in the element that occurs naturally in the Earth’s crust; found where there are Earth’s crust; found where there are many caves under buildingsmany caves under buildings

-radon can seep through cracks and -radon can seep through cracks and holes in the foundations of homes, holes in the foundations of homes, offices, and schools where it adheres to offices, and schools where it adheres to dust particlesdust particles

DO You Have A Radon DO You Have A Radon Detector?Detector?

-when people inhale the dust, radon -when people inhale the dust, radon enters their lungs – destroys the DNA enters their lungs – destroys the DNA in the cells that line air passagesin the cells that line air passages

-can lead to lung cancer especially -can lead to lung cancer especially among people who smokeamong people who smoke

-radon is the second leading cause of -radon is the second leading cause of lung cancer in the USlung cancer in the US

AsbestosAsbestos AsbestosAsbestos – several minerals that form in – several minerals that form in

long, thin fibers and are valued for their long, thin fibers and are valued for their strength and resistance to heatstrength and resistance to heat -primarily used as an insulator and fire -primarily used as an insulator and fire

retardantretardant -it was banned in the early 1970s-it was banned in the early 1970s -exposure to asbestos in the air is -exposure to asbestos in the air is

dangerous – the fibers that are inhaled dangerous – the fibers that are inhaled can cut and scar the lungscan cut and scar the lungs

-causes the disease -causes the disease asbestosisasbestosis difficulty difficulty breathing – lead to heart failurebreathing – lead to heart failure

-billions of dollars have been spent in -billions of dollars have been spent in removing asbestos from school buildings- removing asbestos from school buildings- all gone by 1997all gone by 1997

D. Noise PollutionD. Noise Pollution Noise is a pollutant when it affects Noise is a pollutant when it affects

human health and quality of human lifehuman health and quality of human life -airplanes, construction equipment, city -airplanes, construction equipment, city

traffic, factories, home appliances, lawn traffic, factories, home appliances, lawn mowers, etc.mowers, etc.

-health problems include loss of -health problems include loss of hearing, high blood pressure, and hearing, high blood pressure, and stressstress

-can cause loss of sleep which may lead -can cause loss of sleep which may lead to decreased productivity at work and to decreased productivity at work and in the classroomin the classroom

DecibelsDecibels Decibels (dB)Decibels (dB) – measured the intensity of – measured the intensity of

soundsound -the quietest sound that a human ear can -the quietest sound that a human ear can

hear is represented by 0 dB (decreases hear is represented by 0 dB (decreases over age of 30)over age of 30)

-for each increase in decibel intensity, the -for each increase in decibel intensity, the decibel level is 10 times higher than the decibel level is 10 times higher than the previous levelprevious level

-20dB is 10 times the intensity of 10dB, -20dB is 10 times the intensity of 10dB, and 30 dB is 100 times the intensity of and 30 dB is 100 times the intensity of 10dB10dB

Your iPod may be Your iPod may be hurting you!hurting you!

-120dB is the threshold of pain-120dB is the threshold of pain -permanent deafness may come as a -permanent deafness may come as a

result of continuous exposure to result of continuous exposure to sounds over 120 Dbsounds over 120 Db

How can noise pollution harm the How can noise pollution harm the environment?environment?

E. Light PollutionE. Light Pollution Light pollution does not present a Light pollution does not present a

direct hazard to human healthdirect hazard to human health -negatively affects our environment-negatively affects our environment -diminishes our view of the night sky-diminishes our view of the night sky -energy waste when light is directed -energy waste when light is directed

upward to the skyupward to the sky

III. Acid PrecipitationIII. Acid Precipitation A. What Causes Acid Precipitation?A. What Causes Acid Precipitation?

Acid precipitationAcid precipitation – precipitation – precipitation such as rain, sleet or snow that such as rain, sleet or snow that contains a high concentration of acidscontains a high concentration of acids

-when fossil fuels are burned, they -when fossil fuels are burned, they release oxides of sulfur and nitrogenrelease oxides of sulfur and nitrogen

-when the oxides combine with water -when the oxides combine with water in the atmosphere to form sulfuric acid in the atmosphere to form sulfuric acid and nitric acid which falls as acid and nitric acid which falls as acid precipitationprecipitation

Acid RainAcid Rain

the acidic water flows over that the acidic water flows over that through the ground and into lakes, through the ground and into lakes, rivers, and streamsrivers, and streams

-acid precipitation can kill living -acid precipitation can kill living things and result in the decline or things and result in the decline or loss of some local animal and plant loss of some local animal and plant populationspopulations

the the pHpH number is a measure of how number is a measure of how acidic or basic a substance is.acidic or basic a substance is.

ranges from 1-14 the lower the ranges from 1-14 the lower the number the more acidic, the higher number the more acidic, the higher the number the more basicthe number the more basic

7 is neutral7 is neutral pure water has a pH of 7 and normal pure water has a pH of 7 and normal

precipitation is slightly acidic (5.6) precipitation is slightly acidic (5.6) because atmospheric carbon dioxide because atmospheric carbon dioxide

CO2 dissolves into the precipitation CO2 dissolves into the precipitation and forms carbonic acidand forms carbonic acid

normal precipitation is about 5.6 & normal precipitation is about 5.6 & precipitation is considered acidic if it precipitation is considered acidic if it drops below 5 drops below 5

B. How Acid Precipitation B. How Acid Precipitation Affects Soils and PlantsAffects Soils and Plants

Acid precipitation can cause a drop in the Acid precipitation can cause a drop in the pH of soil and waterpH of soil and water

called called acidificationacidification – an increase in the – an increase in the concentration of acidconcentration of acid

Acidification affects soilAcidification affects soil nutrients are dissolved and washed away by nutrients are dissolved and washed away by

rainwaterrainwater causes aluminum and other toxic metals to causes aluminum and other toxic metals to

be released and possibly absorbed by plantsbe released and possibly absorbed by plants aluminum causes root damagealuminum causes root damage sulfur dioxide in water vapor clogs the sulfur dioxide in water vapor clogs the

openings on the surfaces of plantsopenings on the surfaces of plants

C. Acid Precipitation and C. Acid Precipitation and Aquatic EcosystemsAquatic Ecosystems

Aquatic organisms are adapted to live in Aquatic organisms are adapted to live in an environment with a particular pH an environment with a particular pH rangerange

-if acid precipitation falls into a lake and -if acid precipitation falls into a lake and changes the water’s pH it can kill aquatic changes the water’s pH it can kill aquatic plants, fish, and aquatic animalsplants, fish, and aquatic animals

acid causes aluminum to leach out of the acid causes aluminum to leach out of the soil surrounding a lakesoil surrounding a lake

aluminum accumulates in the gills of fish aluminum accumulates in the gills of fish and interferes with oxygen and salt and interferes with oxygen and salt exchangeexchange

fish are slowly suffocatedfish are slowly suffocated

-effects are worse in the spring – when -effects are worse in the spring – when acidic snow that accumulated in the acidic snow that accumulated in the winter melts and rushes into lakes and winter melts and rushes into lakes and other bodies of waterother bodies of water

causes a rapid pH change called causes a rapid pH change called acid acid shockshock - this causes large numbers of - this causes large numbers of fish in a population to diefish in a population to die

affects the reproduction of fish and affects the reproduction of fish and amphibians – produce fewer eggs, eggs amphibians – produce fewer eggs, eggs do not hatch, offspring that do survive do not hatch, offspring that do survive often have birth defects and cannot often have birth defects and cannot reproducereproduce

To counteract the effects of To counteract the effects of acid precipitation on acid precipitation on aquatic ecosystemsaquatic ecosystems

some states in the US and some some states in the US and some countries spray powdered limestone countries spray powdered limestone (calcium carbonate) on acidified (calcium carbonate) on acidified lakes to help restore the natural pH lakes to help restore the natural pH levellevel

cannot be spread to offset all acid cannot be spread to offset all acid damage to lakesdamage to lakes

biggest way is to reduce pollution biggest way is to reduce pollution itselfitself

D. Acid Precipitation and D. Acid Precipitation and HumansHumans

Acid precipitation can affect humans Acid precipitation can affect humans in a variety of waysin a variety of ways

toxic metals such as aluminum and toxic metals such as aluminum and mercury can be released into the mercury can be released into the environment when soil acidity environment when soil acidity increasesincreases

can find their way into crops, water, can find their way into crops, water, and fish – then poison the human and fish – then poison the human bodybody

lead to increase in respiratory lead to increase in respiratory problems in a community’s childrenproblems in a community’s children

-decreases in the number of fish can -decreases in the number of fish can influence the livelihood of influence the livelihood of commercial fisherman and people commercial fisherman and people involved in sport-fishing industryinvolved in sport-fishing industry

forestry is affected when acid forestry is affected when acid damages trees (killing many conifers damages trees (killing many conifers in East TN and the Smokey in East TN and the Smokey Mountains)Mountains)

Acid precipitation can dissolve the Acid precipitation can dissolve the calcium carbonate in common calcium carbonate in common building materials such as concrete building materials such as concrete and limestoneand limestone

important and historic monuments important and historic monuments are being worn awayare being worn away

Damage to steel bridgesDamage to steel bridges

E. International Conflict E. International Conflict and Cooperationand Cooperation

One problem in controlling acid One problem in controlling acid precipitation is that pollutants may precipitation is that pollutants may be released in one geographical area be released in one geographical area and fall to the ground hundreds of and fall to the ground hundreds of kilometers awaykilometers away

-Almost half the acid precipitation -Almost half the acid precipitation that falls in SE Canada results from that falls in SE Canada results from pollution produced in Ohio, Indiana, pollution produced in Ohio, Indiana, Pennsylvania, Illinois, Missouri, Pennsylvania, Illinois, Missouri, West Virginia, and TennesseeWest Virginia, and Tennessee

Solving the problem has Solving the problem has been difficultbeen difficult

-Canada and US signed the Canada--Canada and US signed the Canada-US Air Quality Agreement in 1991US Air Quality Agreement in 1991

both countries agreed to reduce both countries agreed to reduce acidic emissions that flowed across acidic emissions that flowed across the borderthe border

sulfur dioxide emissions have sulfur dioxide emissions have improved since 1970s (no lead in improved since 1970s (no lead in gas!)gas!)

China still burns large amounts of China still burns large amounts of high-sulfur coal without pollution high-sulfur coal without pollution controlscontrols

ChinaChina

produces acid precipitation in other produces acid precipitation in other parts of Asia far from the coal-parts of Asia far from the coal-burning power plants in Chinaburning power plants in China