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Fuels and Exposure –
Is It Really the Fuels?
Douglas R. Lawson
National Renewable Energy [email protected]
Environmental Health, Energy, and Transport:Bringing Health to the Transportation Fuel Mixture
Roundtable on Environmental Health Sciences, Research, and MedicineInstitute of Medicine, National Academy of Sciences
Washington, DCNovember 29, 2007
Outline of Presentation
• Introduction: ozone and PM
• Accuracy of mobile source emission inventories
and future projections
– Inventories provide the basis for future regulation
• Real-world vehicle emissions
• MSATs and E10
• Comparative toxicity studies – fuels vs.
lubricating oil
• The future?
Nonattainment Areas for Ozone and PM2.5
(2004) No. of Counties
with Monitors
exceeding the
NAAQS
• CO 0
• Lead 1
• SO2 0
• NO2 0
• PM10 12
• PM2.5 82
• O3 297
“Ozone and PM Are Our Highest Priority” – from “Air Quality Management in the
21st Century,” John Bachmann, EPA, October 18, 2005
Evolution of California Auto Controls(Implementation: 1963 – 1993)
0
2
4
6
8
10
12
14
1963
1965
1967
1969
1971
1973
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
g/m
ile N
MV
OC
+ N
Ox
Positive Crankcase Ventilation
Exhaust Standards
EGR
Oxidation Catalyst
Three Way CatalystOn-Board Computer
Advanced ComputerFuel Injection
O2 Sensor
Phase 1 Gasoline
Ref: A. Lloyd, 13th CRC On-Road Vehicle Emissions Workshop, San Diego, CA, April 2003
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
g/m
ile N
MV
OC
+ N
Ox
Evolution of California Auto Controls(Implementation: 1994 – 2010)
Low Emission Vehicle I
Phase 2 Gasoline
Low Emission Vehicle II
Ref: A. Lloyd, 13th CRC On-Road Vehicle Emissions Workshop, San Diego, CA, April 2003
Ozone trends in the South Coast Air Basin 1973 through 2006
0
0 .1
0 .2
0 .3
0 .4
0 .5
0 .6
7 3 7 4 7 5 7 6 7 7 7 8 7 9 8 0 8 1 8 2 8 3 8 4 8 5 8 6 8 7 8 8 8 9 9 0 9 1 9 2 9 3 9 4 9 5 9 6 9 7 9 8 9 9 0 0 0 1 0 2 0 3 0 4 0 5 0 6
1 -h r M a x 1 -h r 3 y r 4 th H i 8 -h r M a x 8 -h r 3 y r A ve 4 th H i
The California Air Resources Board says that “Cleaner-burning gasoline reduces smog-forming
emissions from motor vehicles by 15 percent.” (http://www.arb.ca.gov/fuels/gasoline/cbgupdat.htm).
In which year was CBG introduced?
4th Maximum 8-hr. Ozone
Denver Area
0.000
0.010
0.020
0.030
0.040
0.050
0.060
0.070
0.080
0.090
0.100
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
*4th
Maxim
um
8-H
r. O
zo
ne (
pp
m)
NREL R. Flats-N Chatfield FC-W
Mobile Sources Largest Contributor
to Urban Air Quality
• Why are we having so much difficulty in reducing ambient ozone (and PM) levels?
• New vehicle certification standards have reduced emissions as much as 99%– Is it impossible to reduce ambient ozone (and
PM) levels?
– Are we not doing enough of everything?, or
– Are our control programs not doing enough of the right thing?
Projected Contributions of Mobile
Sources to Los Angeles Air Quality
• “It is apparent that by 1980, motor vehicles will not be the major source of hydrocarbons and oxides of nitrogen, and greater emphasis will have to be placed on emissions from nonvehicular sources.” – Air Pollution Control in California, 1971 Annual Report, page 34.
• “Contribution to VOC by mobile sources is reduced due to the CARB programs. On the contrary, area sources become major contributors to VOC emissions (from 28% in 1997 to 36% in 2010).” 2003 South Coast AQMD, Appendix 3, page III-2-15.
• “However, contribution to VOC by mobile sources is reduced due toCARB regulations over time. Area sources become major contributors to VOC emissions (from 27 percent in 2002 to 42 percent in 2020).”, Draft 2007 South Coast AQMP, Appendix III, page III-2-14.
“Forecasting is difficult, especially when it involves the future.” Quote attributed
to C. Stengel or Y. Berra, depending on the source.
Nationwide PM2.5 Emission Inventory, 2002
www.epa.gov/ttn/chief/trends/index.html#tables
0
500
1,000
1,500
2,000
2,500
Fuel C
ombus
tion
Indu
stria
l Pro
cess
es
Misc
ella
neous
Fugiti
ve D
ust
Mob
ile, G
asolin
e
Mob
ile, D
iese
l
Kil
oto
ns/
year
Phoenix PM2.5 Comparison
5%
17%
16%
35%
14%
13%
Gasoline Exhaust Diesel Exhaust Crustal/Soil Vegetative Burning Secondary Sulfates Secondary Nitrates
Emission Inventory Ambient Data/Receptor Modeling
28%
14%
19%
8%
16%
15%
Refs: Emission Inventory, EPA OAQPS, 1997; Ambient Results: Lewis et al., JAWMA, 2003
0
4000
8000
12000
16000
80 82 84 86 88 90 92 94 96 98 00 02 04
Year
To
ns/D
ay
0
25
50
75
100
Days >
8-h
r F
ed
Std
Tons/Day (current est.) 1999 Almanac
2006 Almanac Days >8-hr Fed Std
Mobile Source Emission Inventory Reality Check:
South Coast Air Basin CO Trends Ambient vs. Inventory, 1980-2005
2.4x
1987 SCAQS Tunnel Study: On-road mobile emissions were 2.7 and 3.8 times
higher for CO and NMHC than EMFAC7C model predictions
Mobile Source Emission Inventories
• Consistently underestimated on-road gas- and particle-phase mobile emissions
• Have always been too optimistic for effectiveness of future in-use controls
• Never have reconciled the present version of the model with ambient data or tunnel studies (“top down vs. bottom up”)
• Always estimate(d) that nontailpipe HC are roughly equal to tailpipe HC
• MOBILE and EMFAC emission models are very precise with unstated accuracy
• More difficult model estimation for non- or off-road mobile emissions!
Nationwide On-
Road Idle HC
Emissions
EPA’s 1985 National
Tampering Survey
6498 vehicles
Ref: Lawson et al. 1996
On average, fleet emissions increase as vehicles age; mean fleet emissions driven by high emitters; median vehicle is clean
Most new cars are clean; a few new vehicles are dirty; most old cars are “clean”
New vehicles irrelevant to air quality
1983 (
25)
1985
1987
1989
1991
1993
1995
1997
1999
2001 (
1113)
2003
0.000
0.050
0.100
0.150
0.200
0.250
Average HC
Emissions, %
Model Year
Cleanest Quintile
2nd Cleanest
Marginal
Dirtier
Dirtiest Quintile
Remote Sensing HC Emissions by Quintile
Speer Blvd./I-25 (Denver)
1983 (
25)
1985
1987
1989
1991
1993
1995
1997
1999
2001 (
1113)
2003
0.0
1.0
2.0
3.0
4.0
5.0
6.0
% of Total HC
Model Year
Cleanest Quintile
2nd Cleanest
Marginal
Dirtier
Dirtiest Quintile
Dec. 3, 5, 6, 2002
10,015 Measurements
Ref: http://www.feat.biochem.du.edu
1995 Toyota Camry (No. 1-1) -- 47,502 miles
0
20
40
60
80
0 400 800 1200 1600 2000 2400 2800 3200Seconds
Speed, mph
0
200
400
600
800CO Emissions, mg/s; 1.80 g/mi
0
10
20
30
40HC Emissions, mg/s; 0.07 g/mi
0
10
20
30
40
50 NOx Emissions, mg/s; 0.35 g/mi
0.0
0.1
0.2
0.3
0.4
0.5 PM Emissions, mg/s; 3.42 mg/mi
0.000
0.002
0.004
0.006
0.008
0 400 800 1200 1600 2000 2400 2800 3200Seconds
Black Carbon Emissions, mg/s
Speed, mph
Second-by-
second data
from a LD
spark-ignition
vehicle, tested
over an
aggressive
cycle on a
chassis
dynamometer
during our
Gasoline/
Diesel PM Split
Study in Los
Angeles, 2001.
Note: Vehicle
six years old
with ~50K on
the odometer.
0
200
400
600
800
Seconds
Cold Phase Warm Phase
CO Emissions, mg/sec; 2.28 g/mi (cold); 1.44 g/mi (warm)
0
10
20
30
40
Seconds
Cold Phase Warm Phase
HC Emissions, mg/sec; 0.16 g/mi (cold); 0.01 g/mi (warm)
01020304050
Seconds
Cold Phase Warm Phase
NOx Emissions, mg/sec; 0.46 g/mi (cold); 0.26 g/mi (warm)
0.0
0.1
0.2
0.3
0.4
Seconds
Cold Phase Warm Phase
PM Emissions, mg/sec; 7.7 mg/mi (cold); 0.2 mg/mi (warm)
0.0000.0020.0040.0060.008
0 200 400 600 800 1000 1200 1400Seconds
Cold Phase Warm Phase
BC Emissions, mg/sec
1995 Toyota Camry (No. 1-1) -- 47,502 miles
0
20
40
60
80
0 200 400 600 800 1000 1200 1400Seconds
Speed, mph
0.00
0.10
0.20
0.30
0.40
0.50
0.60
Em
issio
n R
ate
, m
g/m
i
Benz(a)anthracene Chrysene Benzo(b+j+k)fluoranthene Benzo(a)pyrene Indeno[123-cd]pyrene Dibenzo(ah+ac)anthracene
Spark Ignition Emissions of PAH (POM) Listed as MSATs
0.000
0.001
0.002
0.003
0.004
0.005
0.006
SI Vehicle Profile
Fra
ctio
n o
f P
M M
ass
CW
CW
CW
CW
SMOKERSNewer Vehicles
Older VehiclesCW
Colorado’s OBD II Study Data10 high temperature 1996+ vehicles were procured for lab testing
• All vehicles were tested in I/M lanes at temp. > 90 degrees
• All vehicles failed two IM240 tests in the I/M lanes
• High emissions could not be replicated at the CDPHE lab
• All vehicles < cert. values on the FTP
• No repairable emissions
0
0.5
1
1.5
2
2.5
Grams Per Mile
1st I
M24
0 Tes
t
2nd
IM24
0 Tes
t
Lab IM
240
Test
HC CO/10
0%
5%
10%
15%
20%
25%
30%
Percent Failure
1982 1986 1990 1994 1998 2002
<90 Degrees
>=90 Degrees
Model Year
<90 Degrees >=90 Degrees
Colorado’s IM240 Fail Rates by TemperatureLight-duty VehiclesOct. 2002 – Sept. 2003
N=427,146
Overall
I/M Failure Rates – Temperature Sensitivity(Change in Sensitivity with Change in Ethanol Market Share in Denver Area)
Market Share Reported By Ethanol Management Corporation
0
1
2
3
4
5
6
7
8
9
10
0 10 20 30 40
Sensitivity vs EMC
Market Share
Linear (Sensitivity vs
EMC Market Share)
Ethanol Market Share (percent)
Sen
siti
vit
y
( %
Fai
l R
ate
/ T
emp
erat
ure
) x
100
1999
1998
2001 2002
2000
2003
Y= 24x + 0.9
R = 0.982
Ref: R. Barrett and D. Stedman, 14th CRC On-Road Vehicle Emissions Workshop, San Diego, CA, 2004
Comparative Toxicity of Particulate and Semi-Volatile Organic
Emissions from Normal and High-Emitting Gasoline, Diesel and
Compressed Natural Gas Engines
1. PM and vapor-phase SVOCs from vehicles on chassis dynamometers (SwRI)
Gasoline G (normal emitter) 5 1982-1996 automobiles, 35 – 190K mi
BG (black smoker) 1976 malfunctioning pickup, 199K mi
WG (white smoker) 1990 malfunctioning automobile, 185K mi
Diesel D (normal emitter) 3 1998-2000 automobiles & pickup, 7- 48K mi
HD (high emitter) 1991 malfunctioning pickup, 27K mi
CNG NT (new technology) 2002 with oxidation catalyst, 216 mi
(transit buses) NE (normal emitter) 1997, no after-treatment, 134K mi
HE (high emitter) 1992, retired with 250K miles
2. Chemistry analyzed in detail (DRI)
3. Instilled combined PM+SVOC (in original mass ratios) into rat lungs, and
measured inflammation at 24 hr by bronchoalveolar lavage (LRRI)
4. Compared inflammatory potential (average of 5 variables) per unit of mass (LRRI)
5. Used multivariate analysis (PCA-PLS) to identify components co-varying most
closely with toxicity (LRRI)Seagrave et al., Toxicol. Sci. 70:212, 2002McDonald et al., Environ. Health Perspect. 112:1527, 2004
Zielinska et al., J. Air Waste Man. Assoc. 54:1138, 2004
Seagrave et al., Toxicol. Sci. 87:232, 2005
0
0.5
1
1.5
2
2.5
3
3.5
G BG WG D HD NT NE HE
----- Gasoline ------ -- Diesel -- --------- CNG --------
----------------------------------------------------------------------
Bacterial Mutagenicity
Per Unit of Mass,
Relative to Normal
Gasoline
(Salmonella T-98)
Comparison of Bacterial Mutagenicity
•••• Per unit of PM+SVOC mass, normal gasoline and diesel had similar
mutagenicity
•••• Masses from normal and high emitting CNG buses were the most
mutagenic
0
1
2
3
4
5
6
7
G BG WG D HD NT NE HE
-----------------------------------------------------
Inflammatory Potential
Per Unit of Mass,
Relative to Normal
Gasoline
----- Gasoline ------ -- Diesel -- --------- CNG --------
Comparison of Lung Inflammatory Potential
•••• Per unit of PM+SVOC mass, normal gasoline and diesel had similar potency,
CNG had lower potency
•••• Mass from high-emitting gasoline & diesel vehicles was more toxic
Observed
Predicted
2.01.51.00.50.0
2.0
1.5
1.0
0.5
0.0
High EmitNew Tech Norm Emit
D30G30
HD
D
WG
BG
G
Obseved vs Fitted Inflam. Histopatholgy
....
WG
••••
HD
••••BG
D
••••
G
NT HE NE ••••
•••• ••••
Multivariate Analysis Implicated Lubricating Oil
•••• Models to predict relative responses based on composition were optimized
•••• Composition variables were ranked by their influence on the models
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
S-18H-7
H-12
O2TC
S-4H-6
E2TC
H-5S-9S-5
H-16
S-10
S-1H-3
H-15
S-14
S-3H-8S-8
S-20
S-19
S-17
S-7
S-11H-4EC
S-12
S-2
H-11
H-10
H-9
PartOC
S-13
H-2H-1
S-16
H-14
H-13
S-6
SO4
E3TC
EarthMet
NonMetTC
PM
SVOC
O1TC
4ringPAH
Metalloi
3AMet
O3TC
5ringPAH
O4TC
NO3
E1TC
PMPAH
>5ringPA
TransMet
TotPAH
SVOCPAH
3ringPAH
4AMet
2ringPAH
S-15
NH4
OxyPAH
NitroPAH
OPTC
VIP
•••• 27 of the top 30 variables were hopanes or steranes, markers of
crankcase lube oil
Example: model fitted to histopathology scores
Light-Duty Vehicle Emissions• Light-duty vehicles have been built “clean” since 1982• High-emitter “wall” has progressed forward with passage of time;
fleet turnover has somewhat reduced the number of high emitters,but a small fraction (~5%) produces over half the on-road tailpipe emissions. The U.S. will not attain the national ambient air quality standards until the high emitter problem is solved. Adopting California’s LEV standards does little, if anything, to improve air quality.
• I/M programs, depending upon configuration, have done much less to reduce emissions than the models predict. In some locations, there has been no empirically observed benefit from I/M programs
• High emitters are high emitters regardless of the fuel used (i.e., treating the symptom rather than the problem)
• Oxygen in gasoline (lower level E-XX blends) produces increased permeation (nontailpipe) emissions of VOC relative to non-EtOHcontaining gasoline
• Increased carbonyl emissions (formaldehyde and acetaldehyde –and likely many more oxygenated species) are produced by oxygenated gasoline
Monitoring Stations
A – Azusa
L – Los Angeles, N. Main
P – Pico Rivera
U – Upland
400
360
120
160
200
28080
2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
log N
Ox (
pp
b)
log VOC (ppbC)
Ozone (ppb)
400
360
120
160
200
28080
2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.42.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
log N
Ox (
pp
b)
log VOC (ppbC)
Ozone (ppb)
P
LU
A
A
L U
P
Los Angeles North Main 1987
Azusa 1987
L
A
A
L
P
LU
A
A
L U
P
Los Angeles North Main 1987
Azusa 1987
L
A
Los Angeles North Main 1987
Azusa 1987
L
A
A
L
Mean Wednesday
± 1 sigma
Mean Sunday
± 1 sigma
1987-2010 VOC, NOx and Ozone in Los Angeles
Weekday VOC and NOx
emissions in 2010 are
projected to be similar
to weekend emissions in
2000. Hence, little, if
any, ozone reduction.
SCAQS 1987
Weekend 2000 AND
Weekday 2010
WeekdayWeekday
20002000