Time：14:00-17:00, 16 September
Venue：Lecture Hall 221, SESS (Building No. 16)
Speaker：Mikinori Kuwata, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University. His research area is atmospheric chemistry, especially focusing on aerosol particles. He has published more than 60 papers on international journals such as PNAS, Environ. Sci. Technol., etc.
Abstract：Atmospheric temperature varies over a wide range. For instance, in northern China, temperatures can drop to -20 °C (or even lower) during winter, while they can exceed 30 °C in summer. Temperature influences aerosol particle properties such as viscosity. These changes further affect chemical reactivity. Although this concept was established decades ago, most studies have focused on trapped super-micrometer particles or particles deposited on a substrate. Experimental studies on suspending sub-micrometer particles—which dominate atmospheric number concentrations—remain scarce. We have developed several key experimental tools for investigating the temperature dependence of thermodynamic properties and aerosol chemistry in sub-micrometer particles. These techniques include low-temperature HTDMA, impactors, and aerosol flow tubes. We applied these instruments to study cooking organic aerosol, biomass burning organic aerosol, and their surrogates. In this seminar, I will discuss (1) how the long atmospheric chemical lifetime of cooking organic aerosol can be explained by accounting for temperature, and (2) how enhanced viscosity alters the hygroscopicity of aerosol particles in low-temperature environments.
