Nature of Air Pollution in California
Bart Croes, ChiefResearch Division
Unique, Adverse Meteorology Lowest Per Capita Emission Targets
Onshore circulation pattern, high temperatures, stagnant air masses, and mountain ranges that trap pollutants lead to ...
Population Carrying Capacity (VOC+NOX) (million) (tpd) (lb/person/yr) Los Angeles 16.9 840 36San Joaquin Valley 4.1 630 69Houston 5.5 1360 181
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Air pollution causes premature deathCalifornia estimates
Pollutant Annual Deaths*
PM2.5 7,300 to 11,000
Ozone 300 to 1000
Toxic Air Contaminants <400
*2006-2008 for PM2.5; 2005 for ozone and TACNote: 233,00 total deaths in 2010 3
Cancer risks from airborne toxics* (90% of risk from traffic pollutants)
Benze
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1,3-B
utad
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Hexav
alent
Chr
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Form
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Perc
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ethyle
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All Oth
ers
Diesel
PM
* Estimated 400 cases/year in 2005 (dioxins not included). 4
Major California control programs• Smoke controls began in 1945
– Backyard burning, open burning at garbage dumps, industrial smoke• Hydrocarbon controls begin in 1956
– Gasoline storage tanks and trucks• 1970s
– Industrial SOX controls– Lead and RVP limits for gasoline– Three-way catalysts for passenger cars
• 1980s– On-board diagnostics– Low-sulfur gasoline and diesel
• 1990s– Air toxics
• 2000s and beyond– Light trucks meet same standards as cars– Diesel PM and NOX
– Greenhouse gases
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California emission trends
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Ozone trends in Los Angeles
050
100150200250300350
1965 1970 1975 1980 1985 1990 1995 2000 2005
Days
00.10.20.30.40.50.60.7
Conc
entrat
ion
(ppm
)
Stage 2 Alerts (0.35 ppm)
Stage 1 Alerts (0.20 ppm)
State Standard Exceedances
Peak 1 Hr Ozone
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Ozone trends in California
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
1968 1972 1976 1980 1984 1988 1992 1996 2000 2004 2008
Peak
Con
cent
ratio
n (p
pm)
San Francisco Bay Area
San Diego
San Joaquin Valley
California Standard
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Nitrates and organics dominate California PM2.5 (because of low sulfur emissions)
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PM2.5 exposures across California
1999 20061987
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As PM2.5 declined, has life expectancy increased?
Overall change in U.S. (1980 to 2000)2.7 years improvement (health care, lifestyle, diet)
For every decrease of 10 µg/m3 PM2.50.61 (± 0.20) years improvement
Reductions in PM2.5 accounted for 15% of U.S. life expectancy improvement
Pope et al. (2009) Fine particulate air pollution and life expectancy in the United States, New England Journal of Medicine, 360: 376-386.
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In-vehicle exposures can dominate
• In-Vehicle = Centerline > Roadside >> Ambient• Examples of in-vehicle-to-ambient ratios
– Benzene: 4-8 times higher, 15-20% of total exposure (LA)1
– Diesel: 5-15 times higher, 30 -55% of total exposure (CA)2
– 1,3-Butadiene: 50 to 100 times higher3
• Location of emissions matter– Exhaust high and at front of leading vehicle produces 5
times less in-vehicle impacts than exhaust low and at rear of vehicle
1Rodes, et al. (1998) 2Fruin, et al. (2004) 3Duffy and Nelson (1997)12
Costs of Control0.5% GDP (US 1990-2020)
Benefits of Control$10-95 in health benefits for each $1 of control (US 1970-1990)$30 in health benefits for each $1 of control (US 1990-2020)*
Air pollution control industry – 32,000 jobs and $6.2B (CA 2001)Clean energy industry – 123,000 jobs and $27B (CA 2009)
13U.S. EPA Reports to Congress on The Benefits and Costs of the Clean Air Act (www.epa.gov/air/sect812/index.html)* 1990-2020 uncertainty analysis under development
Summary• California per capita emissions must be lowest in U.S.• Current air pollution health risk
– PM2.5 >> ozone > air toxics• Emissions control focus
– 1950s and 1960s: smoke– 1970s and 1980s: lead, SOX, hydrocarbons and NOX
– 1990s to present: diesel PM and NOX, air toxics, GHG
• Air quality improved 75-90% despite growth• On-road controls have greatest benefits• Benefits much greater than control costs
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Extra slides
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California’s air pollution problem
Unique geography and meteorology confine air pollutants
Over 90% of Californians breathe unhealthy air
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38 M people90 people per km2
24 M gasoline cars1.3 M diesel vehicles1.4 B km per day18 M off-road engines3 large container ports
Air pollution reduced 75-90% despite growth
-100
-50
0
50
100
150
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250
Perc
ent C
hang
e19
68-2
008
CarbonMonoxide
NitrogenDioxide
SulfurDioxide
Population Number of Vehicles
VehicleMiles
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Ozone – Los Angeles peak reduced 70%, hours of exposure by 90%PM10 – annual-average levels reduced 75% Air toxics – lead eliminated, cancer risk reduced 80% (since 1989)Black carbon – reduced 90% (95% by 2020)
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Study of U.S. trucking industryCompared with U.S. population:– All-cause death rate:
• 28% lower
However:– Heart disease death rate:
• Drivers 49% higher• Dockworkers 32% higher
– Lung cancer death rate:• Drivers 10% higher• Dockworkers 10% higherLaden, et al. (2007) Cause-specific mortality in the unionized U.S. trucking industry,
Environmental Health Perspectives, 115:1192-1196. 19
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