air quality and climate connections green and environmental systems regional and urban air quality:...
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Air Quality and Climate Air Quality and Climate ConnectionsConnections
Green and Environmental Systems Regional and Urban Air Quality: Now and in the
FutureNew York Academy of Sciences, NY
February 28, 2007
Arlene M. Fiore([email protected])
Acknowledgments: Larry Horowitz, Chip Levy, Dan Schwarzkopf (GFDL)
Vaishali Naik, Jason West (Princeton U), Allison Steiner (U Michigan) Carlos Ordóñez (Laboratoire d'Aérologie), Martin Schulz (Jülich)
The U.S. smog problem is spatially widespread,
affecting >100 million people [U.S. EPA, 2004]
Annual Average PM2.5 in 2003
U.S. EPA, 2004
Exceeds standard
AEROSOLS (particulate matter)
U.S. EPA, 2006
OZONE
Nonattainment Areas (2001-2003 data)
4th highest daily max 8-hr O3 > 84 ppbv
Air pollutants affect climate by absorbing or scattering radiation
NMVOCsCO CH4
NOx
pollutant sources
+
O3
+OH
H2O
Black carbon(soot) sulfates
T
T
Aerosols interact with sunlight“direct” + “indirect” effects
composition matters!
Surface of the Earth
Greenhouse gasesabsorb infrared radiation
T
more cloud droplets
Smaller droplet size clouds last longer less precipitation
atmospheric cleanser
Radiative forcing of climate (1750 to present):Important contributions from air pollutants
IPCC, 2007
50% anth. NOx
50% anth. CH4
50% anth.VOC
1995(base)
50% anth.VOC
50% anth.CH4
50% anth.NOx
AIR QUALITY: Number of U.S. summer grid-square days with
O3 > 80 ppbvCLIMATE: Radiative Forcing (W m-2)
Fiore et al., GRL, 2002
Double dividend of Methane Controls: Decreased greenhouse warming and improved air quality
Ozone precursors
NOx OH
CH4
Results from GEOS-Chem global tropospheric chemistry model (4°x5°)
CLE A B C
0.2
0.1
0.0
-0.2
-0.1OZONEMETHANE
+0.16 Net Forcing (W m-2)
+0.080.00 -0.08
Reducing tropospheric ozone via methane controls decreases radiative forcing (2030-2005)
Anthropogenic CH4 Emissions (Tg yr-1)
Control scenarios reduce 2030 emissions relative to CLE by:A) -75 Tg (18%) – cost-effective nowB) -125 Tg (29%) – possible with current technologiesC) -180 Tg (42%) – requires new technologies
West and Fiore, 2005; Fiore et al., in prep
Radiative Forcing of Climate
A
B
C
CLE Baseline
How might future changes in aerosols affect climate?
HISTORICAL and FUTURE SCENARIOS
CO2 concentrations
pp
mv
Emissions of Short-lived Gases and Aerosols (A1B)
1880 1920 1960 2000 2040 2080
NOx (Tg N yr-1)
SO2 (Tg SO2 yr-1)
BC (Tg C yr-1)25201510 5 0
250
200
150
100
50
605040302010
Horowitz, JGR, 2006
Large uncertainty in future emissiontrajectories for short-lived species
Pollution controls
A1B
IPCC, 2001
Up to 40% of U.S. warming in summer (2090s-2000s) from short-lived species
From changing well-mixed greenhouse gases +short-lived species
From changing only short-lived species
Warming from increases in BC + decreases in sulfate;depends critically on highly uncertain future emission trajectories
Results from GFDL Climate Model [Levy et al., 2006]
Change in Summer Temperature 2090s-2000s (°C)
Changes in global anthropogenic emissions affect regional air quality
2030 A1
1995 Base caseIPCC 2030Scenario
Anthrop. NOx
emis.Global
U.S.
Methane emis.
A1 +80% -20% +30%
GEOS-Chem Model (4°x5°) [Fiore et al., GRL, 2002]
Rising global emissions may offset U.S. efforts to reduce pollution
longer O3 season
How will changes in climate influence regional air quality?
Probability of daily max 8-h O3 > 84 ppbv vs. daily max. temperature
Observed surface ozone over the U.S. Observed surface ozone over the U.S. correlates strongly with temperaturecorrelates strongly with temperature
Lin et al., 2001
1980-1998 summertimeobservations
Pro
bab
ilit
y
0.5
0.4
0.3
0.2
0.1
0.0 62 71 80 89 98 (°F)
Temperature
New England
Southeast
Los Angeles
How does climate affect air quality?
pollutant sources
strong mixing
(1) Meteorology (stagnation vs. well-ventilated boundary layer)
Degree of mixing
Boundary layer depth
(2) Emissions (biogenic depend strongly on temperature; fires)
T
VOCs
T
(3) Chemistry responds to changes in temperature, humidity
NMVOCsCO, CH4
NOx+ O3+ OHH2O
generally faster reaction rates
Increase with T, drought?
Ozone
CO
Ventilation (low-pressure system)
HEATWAVE
GRGCarlos Ordóñez [email protected] Laboratoire d'Aérologie Toulouse, France
CO and O3 from airborne observations (MOZAIC)
Above Frankfurt (850 hPa; ~160 vertical profiles
Contribution to GEMS, Integrated Project of the 6th EC Framework ProgrammeGEMS-GRG subproject coordinated by Martin Schultz ([email protected])
Pollution build-up during 2003 European heatwave
Stagnant high pressure system over Europe
(500 hPa geopotential anomaly relative to 1979-1995 for 2-14 August, NCEP)
H
Observations during 2003 European heatwave show enhanced biogenic VOC concentrations
Hogrefe et al., EM, 2005
Measurements from August 2003 Tropospheric Organic Chemistry Experiment (TORCH) in Essex, UK, during hottest conditions ever observed in the UKc/o Dr. Alistair Lewis, University of York, UK
con
cen
trat
ion
(p
ptv
) temperature (°C)
BVOCs
= 95 °F
= 86 °F
= 77 °F
Impacts on surface O3 from T-driven increases in reaction rates, humidity, and BVOC emissions
due to changes in climate
Climate-driven O3 increases may counteract air quality improvements achieved via local anthropogenic emission reductions
3 p.m. O3 change (ppbv) in 3-day O3 episode with CMAQ model (4x4 km2), applying T change from 2xCO2
climate (changes in meteorology not considered) [Steiner et al., JGR, 2006]
pp
bv
ppbv
normalized to a +1°C5
4
3
2
1
0reaction humidity BVOC combinedrates
O3 response depends on local chemistry (available NOx)
Changing climate may increase pollution events over the eastern U.S.
Daily max 8-hr O3
(5-year summer mean)
ppbv
Tracer of anthropogenic pollution (July-August)
Simulations using present-day emissions with future climates
Regional CMAQ model (36 km2)with GISS boundary conditionsHogrefe et al., JGR 2004; EM 2005
in GISS global model (4°x5°)[Mickley et al., GRL, 2004]
Rel
ativ
e F
req
uen
cy (
%) 2045-2052 A1B
1995-2002
Increase in frequency and duration of pollution eventsdue to decrease in frequency of mid-latitude storms
Eastern U.S.
Surface O3 change under future climate varies: increases in polluted regions; decreases in
“background”Mean annual change in number of days where daily max 8-hr O3 > 80 ppbv
(2090-2100 A1) – (1990-2000)
MOZART-2 global tropospheric chemistry model with meteorology from NCAR climate model [Murazaki and Hess, J. Geophys. Res., 2006]
More inflow of clean air from Gulf of Mexico
Less trans-Pacific transport
Increase in polluted (high-NOx) regions
Air Quality and Climate Connections: Research Focal Points
Costs and benefits of “win-win” (e.g. BC, CH4) and “win-lose” (e.g. sulfate) strategies for joint mitigation of air pollution and climate forcing
Aerosol feedbacks on climate, globally and regionally
Response of biogenic emissions and fires to changes in climate and land-use
Evolution of air quality with global change (climate + anthropogenic and “natural” emissions)