Asian Aerosols: Current and Future Distributions and Implications to Air Quality and Regional Climate Change (Invited Speaker)

Asian environments contain high levels of aerosols and these have profound impacts on human health and on climate change. Vast regions (>80%) in Asia have PM2.5 concentrations that exceed on an annual basis the WHO guideline of 10 microg/m3, often by factors of 2 to 4. The high aerosol loadings cause a significant dimming at the surface, and mask ~45% of the warming by greenhouse gases. In this paper, we present results using the STEM chemical transport model to help describe the regional distributions and seasonal cycles of Asian aerosols. The seasonal cycles of Asian aerosols are shown to be driven by seasonal variations in emissions associated with combustion processes such as open biomass burning and heating cycles, monsoonal flows that bring strong on-shore flows across large regions, and strong flows across arid and semi-arid regions resulting in large quantities of wind blown dust. We also discuss some of the important impacts of Asian aerosols on human health and the climate system. Finally we look to the future and discuss the implications for aerosol emissions in Asia, and the opportunities for win-win strategies built upon addressing air quality and climate change together. Throughout the paper we focus special attention on black carbon (BC) because of its unique role as the aerosol that acts like a greenhouse gas and warms the atmosphere, and its importance in human health effects.fied by 128.255.70.110 on 8-3-2009-->