Eri Saikawa 1 , Vaishali Naik 1 , Larry W. Horowitz 2 , Junfeng Liu 1 , Denise Mauzerall 1

1. Present & Potential Future Contributions of Sulfate, Black & Organic Carbon Aerosols from China to Global Air Quality, Premature Mortality & Radiative Forcing Eri Saikawa1, Vaishali Naik1, Larry W. Horowitz2, Junfeng Liu1, Denise Mauzerall1 1Princeton University, Princeton, NJ, USA 2Geophysical Fluid Dynamics Laboratory, Princeton, NJ, USA – Submitted to Atmospheric Environment – December 19, 2008 AGU A54C General Contributions: Chemistry and Composition III

2. Background • Fine particulate matter PM2.5 has harmful effects on global air quality & human health • PM2.5 affects radiative forcing on climate • China is a major emitter of PM2.5 and its precursors Beijing, China NYTimes, December 29, 2007

3. Adverse Health Impacts of PM2.5 • Association between PM2.5 ambient concentrations and increased risk of adverse health impacts • Are linear • Have no threshold • Mortality associated with 10 µg/m3 increase in PM2.5 occur within 2 years of exposure – reductions in air pollution can improve public health almost immediately [Pope, 2002, Schwartz et al.,2008]

4. Global radiative forcings due to emissions of aerosols and precursors changes from 1750-2005 Black carbon has positive radiative forcing Sulfate and organic carbon have negative radiative forcing Indirect effects of aerosols are negative [IPCC, WG1 4th Assessment Report, 2007]

5. Objectives Analyze impacts of China’s anthropogenic emissions of SO2, SO42-, OC & BC in 2000 and for three emissions scenarios in 2030 on: • global surface concentrations • annual premature mortality • radiative forcing

6. Methodology • Emission scenarios • With & Without China’s emissions • Calculate change in concentrations due to emissions from China • Global chemical transport model MOZART-2 • Calculate change in annual premature mortality due to China’s aerosols • Calculate change in global radiative forcing • Radiative Transfer Model (RTM)

7. Emission Scenarios 2000: Baseline • CLE (Current Legislation, IIASA) 2030: Future Scenarios • BAU (Business-As-Usual, IPCC SRES A2) • CLE (Current Legislation, IIASA) • MFR (Maximum Feasible Reduction, IIASA)

8. MOZART-2 Global 3-dimensional chemical transport model • Simulates chemistry & transport of 73 species • Horizontal resolution: 1.9° × 1.9° • Vertical levels: 28 from surface to 2.7 mb • Meteorology: Year 2000 NCEP/NCAR reanalysis • 2.5 year simulation with 1.5 years for spin-up

9. Premature Mortality Calculation Concentration-response relationship (4%) based on adjusted mortality relative risk associated with a 10µg/m3 change in PM2.5 for all-cause mortality. Gridded population of the world [Pope et al., 2005] [CIESIN, 2000] Surface SO42- concentrations resulting from China’s anthro emissions in 2000 [µg m-3] Mortality Rate of people 30 years or older [WHO, 2000]

10. Radiative Forcing • GFDL global 3-dimensional radiative transfer model (RTM) • Total net irradiance (solar+terrestrial) at TOA • Horizontal resolution: 2° × 2.5° • Vertical level: 24 from the surface to 3mb • Assumed random cloud overlap • Adjusted radiative forcing • Only direct effects

11. SO42- Impacts of China’s Aerosols on Global Surface Concentrations in 2000[µg m-3] OC BC

12. Impacts of China’s Aerosols on Global Premature Mortality

13. Impacts of China’s Aerosols on Global Radiative Forcings in 2000 [mWm-2] SO42- OC BC Net

14. Impacts of China’s Aerosols on Global Radiative Forcing Unit: mWm-2 China’s SO42-, OC & BCcreate net NEGATIVE radiative forcing

15. Impacts of China’s Aerosols in 2030

16. Conclusion • China’s aerosols have large impacts on global air quality and premature mortality • China’s sulfate produce large negative forcing • Simultaneously reducing: • Aerosols – to protect health • GHGs – to protect climate • is essential!

17. Acknowledgments • Dr. Arlene Fiore, GFDL • Geophysical Fluid Dynamics Laboratory (GFDL) for computational resources

18. Thank you! E-mail: esaikawa@princeton.edu