报告人： Prof. Joel Thornton
报告时间： 2019年11月26日（星期二） 14：00
In many locations, the worst air quality can occur during winter. In the eastern U.S., e.g., substantial decreases in sulfur and nitrogen oxide emissions have not been as effective in reducing fine particulate matter as in summer, such that the highest particulate matter concentrations now occur in winter. Shifts in temperature and radiation between summer and winter lead to dramatic changes in the relevant chemical processes that convert primary pollutants into secondary pollutants of concern for air quality and ecosystem health, such as fine particulate matter, acid and nutrient deposition and long-range transport of ozone precursors. Multiphase processes involving reactions between gases on or in aerosols and clouds are expected to be far more important during winter, there remains significant gaps in our observations of wintertime atmospheric chemistry leading to large discrepancies between air quality model predictions and our expectations for the effects of air quality policies. The Wintertime INvestigation of Transport, Emissions, and Reactivity (WINTER) campaign utilized the U.S. NSF/NCAR C-130 aircraft to study the emissions and chemical fate of reactive nitrogen, sulfur, and organic species across the eastern U.S. I will show the insights discovered as a result of this campaign and discuss how they relate to the effectiveness of air quality policies.
Joel A. Thornton received a B.A. in Chemistry from Dartmouth College (1996), and a Ph.D.in Chemistry from the University of California, Berkeley (2002), working with Professor Ronald Cohen. After a two-year postdoctoral fellowship at the University of Toronto with Professor Jonathan P. D. Abbatt (Chemistry), he joined the faculty in the Department of Atmospheric Sciences at the University of Washington in 2004. He has received several prestigious awards such as NSF CAREER Award (2009), Henry G. Houghton Award from American Meteorological Society (2012), and Ascent Award from American Geophysical Union (2018). He currently serves as editors of Geophysical Research Letters (GRL) and Atmospheric Chemistry and Physics (ACP). His current research interests include the transformations of reactive organic molecules and oxides of nitrogen and their influence on the air quality and climate impacts of atmospheric aerosol particles.