1. AIR POLLUTION AND GLOBAL CHANGE: TOWARDS AN INTEGRATED POLICY
Daniel J. Jacob

2. NUMBER OF PEOPLE LIVING IN U. S
NUMBER OF PEOPLE LIVING IN U.S. COUNTIES VIOLATING NATIONAL AIR QUALITY STANDARDS, 1999
Carbon
monoxide (CO)
EPA [2001]
Lead
Nitrogen
dioxide
124 ppbv
Ozone (O3)
84 ppbv
Particles < 10 mm
(PM10)
Particles < 2.5 mm
(PM2.5)
Sulfur dioxide
(SO2)
Any pollutant

3. GOOD vs. BAD OZONE NOx = NO + NO2: nitrogen oxide radicals
VOC (volatile organic carbon) = light hydrocarbons
and substituted organic compounds

4. MEAN NUMBER OF SUMMER DAYS (1980-1998) EXCEEDING THE U. S
MEAN NUMBER OF SUMMER DAYS ( ) EXCEEDING THE U.S. OZONE AIR QUALITY STANDARD (84 ppbv, 8-hour average)
EPA/AIRS data [Lin et al., 2001]

5. Historical records imply a large anthropogenic contribution to the present-day ozone background at northern midlatitudes
Ozone trend from European mountain observations,
[Marenco et al.,1994]
Preindustrial
ozone models }

6. SURFACE OZONE IN U.S. INCLUDES A ppbv BACKGROUND THAT HAS INCREASED BY ~3 ppbv OVER THE PAST 20 YEARS
8-h daily maximum ozone probability distribution at rural U.S. sites
[Lin et al., 2000]

7. THIS OZONE BACKGROUND IS A SIZABLE INCREMENT TOWARDS VIOLATION OF U. S
THIS OZONE BACKGROUND IS A SIZABLE INCREMENT TOWARDS VIOLATION OF U.S. AIR QUALITY STANDARDS (even more so in Europe!)
Europe
(8-h avg.)
Europe
(seasonal)
U.S.
(8-h avg.)
U.S.
(1-h avg.)
ppbv
preindustrial
present
background

8. SURFACE OZONE ENHANCEMENTS CAUSED BY ANTHROPOGENIC EMISSIONS FROM DIFFERENT CONTINENTS
GEOS-CHEM
model, July 1997
North America
Europe
Asia
Li et al. [2002]

9. RANGE OF ASIAN/EUROPEAN POLLUTION SURFACE OZONE ENHANCEMENTS OVER THE U.S. IN SUMMER as determined from a simulation with these emissions shut off
Subsidence of Asian pollution
+ local production
Max Asian/European pollution enhancements
(up to 14 ppbv) occur at intermediate ozone levels (50-70 ppbv)
stagnation
tropical
air
MAJOR CONCERN
IF OZONE STANDARD
WERE TO DECREASE!
Fiore et al. [2002]

10. EFFECT OF NORTH AMERICAN SOURCES ON PREDICTED EXCEEDANCES OF EUROPEAN AIR QUALITY STANDARD (55 ppbv, 8-h average)
GEOS-CHEM model
results, summer 1997
Number of
exceedance days
(out of 92)
# of exceedance days that would not have been in absence of
N.American emissions
Li et al. [2002]

11. ANNUAL MEAN PARTICULATE MATTER (PM) CONCENTRATIONS AT U. S
ANNUAL MEAN PARTICULATE MATTER (PM) CONCENTRATIONS AT U.S. SITES, NARSTO PM Assessment (draft), 2002
PM10 (particles > 10 mm)
PM2.5 (particles > 2.5 mm)
Red circles indicate violations of national air quality standard:
50 mg m-3 for PM mg m-3 for PM2.5

12. COMPOSITION OF PM2.5 (NARSTO PM ASSESSMENT)

13. ASIAN DUST CLOUD OVER THE WESTERN U.S. (APRIL-MAY 1998)
GOES Satellite Image
PM10 West Coast
R. Husar, Washington U.

14. moderately polluted day
EPA REGIONAL HAZE RULE: FEDERAL CLASS I AREAS TO RETURN TO “NATURAL” VISIBILITY LEVELS BY 2064
Places new emphasis for understanding long-range transport
clean day
moderately polluted day
Acadia National Park

15. TROPOSPHERIC OZONE MAINTAINS THE OXIDIZING POWER OF THE ATMOSPHERE
O2 + hn
STRATOSPHERE
Stratospheric ozone
Tropopause (8-18 km)
TROPOSPHERE ?
Complex non-linear chemistry
Lightning ? hn
hn, H2O
Nitrogen oxides (NOx)
CO, Hydrocarbons ?
Ozone (O3)
Hydroxyl (OH)
The Pacman of the atmosphere!
Fires
Biosphere
Human
activity
physics
chemistry
biology
Ocean

16. CLIMATE FORCING BY AIR POLLUTANTS GLOBAL RADIATIVE FORCING OF CLIMATE, 1750-present [IPCC, 2001]
POLLUTANT-RELATED OH

17. radiative forcing from tropospheric ozone is less well constrained than implied by IPCC 2001 report
Global simulation of late 19th century ozone observations with the GISS GCM
Standard model:
DF = 0.44 W m-2
“Adjusted” model
(lightning and soil NOx decreased,
biogenic hydrocarbons increased):
DF = 0.80 W m-2
[Mickley et al., 2001]

18. BLACK CARBON: A MAJOR “GREENHOUSE” AEROSOL Its forcing is likely underestimated in IPCC 2001 report
DIESEL
DOMESTIC
COAL BURNING
BIOMASS
BURNING
Chin et al. [2000]

19. WHAT DOES THE FUTURE HOLD? Future emission scenarios from IPCC [2001]
A1, A2, B1, B2: different socioeconomic story lines
NOx
A2: “dirty world”
B2: “clean world”
SO2

20. Growth of Asian emissions over the next decades will increase role of background for ozone air quality in U.S.
Anthropogenic
NOx emissions
[IPCC, 2001]
2000
“Optimistic”
IPCC scenario:
OECD, U.S. m20%,
Asia k 50%
2020
109 atoms N cm-2 s-1

21. FUTURE EMISSIONS MAY BE LESS THAN PRESENT FORECASTS IF PUSH IS MADE FOR ENERGY EFFICIENCY AND AIR QUALITY IN DEVELOPING WORLD
Streets et al. [2001]
LINK AIR QUALITY AND CLIMATE CHANGE MITIGATION OBJECTIVES!

22. GETTING A BIG BANG FOR THE BUCK: controlling methane emissions
A 50% reduction in anthropogenic methane emissions would:
yield a fast negative global radiation forcing of 0.37 W m-2
(-0.30 W m-2 from methane, W m-2 from ozone)
decrease the incidence of ozone > 80 ppbv in surface air
over U.S. by more than 50%
[A.M. Fiore, GEOS-CHEM model results, 2002]
Recent methane trend
Historical methane trend

23. IPCC PROJECTION OF FUTURE METHANE EMISSIONS
Can we try to decrease methane emissions instead?