Gregory R. Carmichael Center for Global and Regional Environmental Research, The University of Iowa, Iowa City, USA Climatic Effects & Air Quality: Aerosol/Chemistry Interactions and the Role of Megacities

Mineral Dust BC from Pollution & Fires Aerosols are Pervasive Throughout Asian Environments

Stratus Cirrus A Key Science Issue: Chemistry/Aerosol/Regional Climate Coupling Radiative Forcing Gas-phase Tropospheric Chemistry Tropospheric Aerosols Tropospheric Clouds AnthropogenicBiogenicStratospheric input Generation of inorganic and organic aerosols by gas-to-particle conversion and nucleation Direct effect Sea salt Mineral dust Biomass burning particles Sulfates (via gas-phase chemistry) Carbonaceous particles NH 3 Flux of gaseous species to clouds Cloud processing Tropospheric O 3 Heterogeneous NOx/NOy chemistry Free radical Scavenging ? Alteration of Actinic flux CCN Alteration of cloud albedo (indirect effect) modified after J.H.Seinfeld 1999

(Vicki Grassian –leader)

SULFATE SIZE DISTRIBUTION RADIATIVE FORCING INTERACTIONS OF SO 2 WITH MINERAL AEROSOL CHANGE SULFATE SIZE DISTRIBUTION AS WELL AS THE CHEMICAL LIFETIMES OF SULFUR. THESE INTERACTIONS HAVE IMPLICATIONS FOR RADIATIVE FORCING Song et al., JGR in press

Calculated Fine and Coarse Mode Aerosol Distributions in the Boundary Layer; PEM-WEST B

Calculated Fine and Coarse Mode Aerosol Distributions at 5 km; PEM-WEST B

% Decrease in HO 2 levels due to RXNs on Mineral Aerosol (May 1987)

% Change in O 3 in May 1987 due to: NO x + H x O y Rxns; Direct O 3 Rxn; and Combination

Nitric Acid Reactions with Calcium Carbonate are not Limited to the Surface, and Change the Water Uptake Properties and Particle Morphology Goodman et al., JGR, 105:29053, 2000

Surface reflection Ice cloud Water cloud EP/TOMS Total Ozone (Dobson) Dust Black Carbon Organic Carbon Sulfate Other PM2.5 and Other PM10 Sea Salt absorption by gas-phase species O 3, SO 2 and NO 2 Inputted from STEM 3-D field STEM TOP 15km O 3 (Dobson) below STEM top height TUV TOP 80km Overtop O 3 = STEM on-line TUV overview Output: 30 kinds of J-values for SAPRC99 mechanism

NO 2 3 N 2 O 5 HNO 3 O 3 HO 2 RO 2 O 2 HO RO H 2 O HO 2 2 Emission O 3 O 2 CH 3 COO 2 NO 2 CH 3 COO 2 h h h Ozone variations (%) due to dust Dust Impact on O %Change NO 2 Photolysis Mineral Optical Depth Impact of Aerosols on the Photochemical Oxidant Cycle Through Photolysis Rates SeasonAerosol  Sulfate  Soot  Mineral  TSP impact on O 3 %% + \\\\ Winter Mean \\\ Spring Mean \\\ Summer Mean \\\\ Fall Mean NO x NMHC O 3 HO x UVB % Change

Urban Environments in Asia uAsia presently has ~1 billion urban dwellers, projected to grow to ~3 billion in 2025 u10 Asian Megacities will account for ~40% of GNP in 2025 uEach 1 million urban inhabitants emit average of 25,000 tons of CO 2 every day (six times global per capita average) uIndoor and Outdoor air pollution pose severe human health concerns u 4%/yr urban growth rate in Asia-Pacific region u 23 megacities in 1995 (17 in developing countries) to 36 in 2025 (23 in Asia)

Percentage of Sulfur Emissions by Sector & Fuels for year 2000

% Contribution of Megacities to Total Sulfur Deposition

(b) Figure 2. Comparison of SO 2 Emissions from the Megacities of Asia, ktons/year (a) For year 1975, 1980, 1990, 1995 and 2000 (b) For year 2010 and 2020 from RAINS-Asia 7.52

Integrated Urban AQM Shanghai Province Shanghai 30 o 36’ 120 o 36’ 32 o 122 o East China Sea uForward looking policies which anticipate growth in environmental growth and/or retrofitting are most cost-effective. uPolicy trajectories include (example): distant siting (50 km to 75km); ESP, coal washing; fabric filters and low-NOx burners. uIGCC technology for new power plants and relocation of major industrial estates and power plants to outside the city limits.

Health Benefits due to Sulfur and PM Control in Shanghai

Ambient Air Quality Curve in Shanghai

China Emissions in (Tg)  in China’s emissions (2000 – 1995) (Tg) Total global fossil fuel emission ca~1995 (Tg) Change in China’s emissions as % of global total anthropogenic fuel combustion (%) Temp. Response function  T/  Emissions (K/Tg) 2,4 Estimated Change in global temperatures due to changes in China’s emissions between 1995 and 2000 (K) 3,4 SO % BC % CO 2 3, , % CH % Net change:  = Air Pollution and Climate Issues are Intimately Linked

Urban Air Pollution Control Policies and Technical Options Shanghai Bombay Urban Air Quality Manage- ment Megacities feel the change first. Health impacts as a primary measure, urban centers will react to policy measures faster than a province or a region. Important challenge is how to integrate climate and urban air quality in a manner that enables the evaluation of complex policies.