1. Global Distribution and Transport of Air Pollution Presented at The Haagen-Smit Symposium: From Los Angeles to Global Air Pollution Lake Arrowhead, April 9-12, 2001 Rudolf Husar CAPITA, Washington University, St. Louis

2. Background Global-scale air pollution existed since….. The difference is that now we can observe it! Outline of Presentation Major pollutant sources and emissions Observation-based global chemical climatology of major gases and aerosols Illustration of global-scale dust and smoke events Opportunities and challenges of the the 21 st century

3. Industrial Sulfur Emission Density The regional hot-spots for industrial sulfur emissions are in E. North America, Europe and E. Asia Long Term Trends North America: roughly constant for the past century Europe: Rise after WW II but leveled off since 1990 East Asia: Sharp rise since the 1960s. Regional hot-spots for industrial sulfur emissions Eastern North America, Europe East Asia

4. Continental Surface Visibility (Human Observers) NOAA NCDC Global Summary of the Day (SOD) 7000 Observations Low Visibility High Visibility

5. Extinction coefficient (visibility) for SE Asia The most intense and persistent regional haze is over India During 1997 biomass fires in Indonesia caused unusually intense haze Sep, Oct, NovDec, Jan, Feb

6. The haze over N. America is modest compared to hazy regions of Africa, E. Asia and S. America Extinction coefficient (visibility) for N. America Jun, Jul, Aug Dec, Jan, Feb

7. Haze over China SeaWiFS Industrial haze covers most of Eastern China Haze is confined to low- lying areas and valleys

8. The Asian Dust Event of April 1998 On April 19, 1998 a major dust storm occurred over the Gobi Desert The dust cloud was seen through SeaWiFS, TOMS, GMS, AVHRR satellites The dust transport was followed on-line by an an ad-hoc international group China Mongolia Korea

9. SeaWiFS/TOMS data for April 21 shows dust transport to the Pacific Japan

10. Trans-Pacific Dust Transport The dust cloud traversed the Pacific in 6 days at about 4 km altitude As the dust approached N. America, it subsided to the ground

11. Asian Dust Cloud over N. America On April 27, the dust cloud rolled into North America. The regional average PM10 increased to 65  g/m 3 In Washington State, PM10 exceeded 100  g/m 3 Reg. Avg. PM10 100  g/m 3 Hourly PM10

12. Fine Particle Dust Concentrations (IMPROVE) April 25, 1998 April 29, 1998 May 2, 1998 On April 25, the western U.S. was virtually dust-free. Highest concentration was an April 29. On May 2, the high levels moved (?) to the Colorado Plateau.

13. Summary of Global Air Pollution and Transport The global sulfur emissions have shifted from N. America and Europe to East Asia. The industrial ‘belt’, 30-60 deg N, is dominated by anthropogenic SO x, NO x and O 3. This conforms to the conventional wisdom since the 1970s. Recent satellite data show that NO x, HC and aerosols are dominated by biomass burning in the subtropics and the southern hemisphere. ?? The radiatively active global aerosol is dominated by smoke and dust, rather then by industrial sulfates as we have presumed. Episodic trans-continental transport of dust and smoke (ozone?) can now be detected and modeled routinely. Such extra-jurisdictional ‘pollution’ events cause significant episodic impact on the air quality of N. America.