|Address:||G5703, 5/F, Yeung Kin Man Academic Building (YEUNG),
City University of Hong Kong,
Tat Chee Avenue, Kowloon, Hong Kong SAR
This talk will highlight two topics in atmospheric chemistry: the direct climate impact of carbonaceous aerosols, and tropospheric chlorine chemistry. They both have potentially large but still very uncertain roles in global climate and air quality.
Atmospheric aerosols are important due to their adverse effects on human health and their radiative effects on climate, which are significant and very uncertain factors contributing to global climate change. In estimating the direct radiative effect (DRE), the absorption from carbonaceous aerosols, including black carbon (BC) and brown carbon (BrC, a component of organic aerosol, OA), are highly uncertain. This presentation will address this uncertainty by combining models and observations to better constrain the optical properties and radiative impact of carbonaceous aerosols. Our work suggests that policies for reducing emissions of carbonaceous aerosols may have a limited impact on mitigating global climate warming.
Mobilization of chloride (Cl-) from sea salt aerosol and 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. Here I will present a comprehensive analysis of chlorine chemistry within the framework of the GEOS-Chem global chemical transport model, its coupling to other halogens, and the implications for tropospheric oxidants and air quality.
Dr. Xuan Wang received his Ph.D. in Environmental Chemistry from Massachusetts Institute of Technology in 2017. He is currently a postdoctoral fellow at Harvard University. His research interests include atmospheric gases and aerosols and their effect on air quality and climate, with specific focus on modeling the chemistry process in troposphere.