1 Research Report for Japan Society for the Promotion of Science

Program title: abundances and isotope compositions of size-resolved organic aerosols in the Eastern Asia atmosphere (1) Purpose of Proposed Research Atmospheric aerosols have played an important role in global climate change and impact on human health. Airborne particles in different size have different chemical and physical properties and toxicities. In general, particles with different size have different residence time in the atmosphere and different hygroscopicity. Thus their activities as cloud condensation nuclei (CCN) are different. On the other hand, fine particles can penetrate into lung tissue much more deeply than coarse particles. Therefore, it is very important to characterize atmospheric particles in different sizes. However, studies on size-segregated aerosols are very sparse, of which only focused on normal alkanes and PAHs. Furthermore, these studies were limited on a very few sites. East Asia has been experiencing a fast urbanization and industrialization, emissions from fossil fuel combustion has sharply increased, leading to the excess of atmospheric nitrogen dioxide in East Asia over those in North America and Europe. In other words, anthropogenic activities in East Asia may be changing the local and global atmospheric compositions. Therefore, it is very necessary to study the size-segregated particles in the East Asia atmosphere. The main purpose of my proposed research in Japan is the chemical characterization of organi