Time: 9:30-10:30, 24th December 2018
Venue: Lecture Hall (221), Building No.16,Weijin Campus, Tianjin University
Speaker: Dr. WANG Xuan, Postdoctoral fellow, School of Engineering and Applied Sciences, Harvard University
Topic: The role of chlorine in tropospheric chemistry
Abstract:
Mobilization of chloride (Cl-) from sea salt aerosol as well as anthropogenic emissions are large sources of chlorine gases to the troposphere. These gases may generate chlorine radicals with a broad range of implications for tropospheric chemistry including the budgets of ozone, OH (the main tropospheric oxidant), volatile organic compounds (VOCs), nitrogen oxides, aerosol composition, other halogens, and mercury. Here I present a comprehensive analysis of this chemistry within the framework of the GEOS-Chem chemical transport model (CTM). This global simulation suggests that the global mean tropospheric concentration of Cl atoms (a particularly strong oxidant) is ~620 cm-3, contributing 1.0% of the global oxidation of methane. Chlorine chemistry decreases the global model burdens of tropospheric ozone and OH slightly, mainly through Cl- mediated heterogeneous mobilization of bromine radicals. Based on this new model, I would also present several new findings on the role of chlorine on regional air quality and stratospheric ozone loss.
