Hygroscopicity of atmospheric aerosol particles transported from East Asian continent


Yange Deng and Michihiro Mochida at Division of Meteorological and Atmospheric Research (YD: a former member), Hiroaki Fujinari in Graduate School of Environmental Studies, Nagoya University (a former student), and their research team have characterized the hygroscopicity of atmospheric aerosols in Okinawa, a receptor of air masses from Asian continent, and its relationship to chemical composition. Further, they have shown that “offline analysis”, that is, the analysis of atmospheric aerosol samples in a laboratory, is a useful means for the analysis of their hygroscopicity. This study was performed in collaboration with Tokyo University of Agriculture and Technology, Hokkaido University, Chubu University, Sun Yat-sen University, China Meteorological Administration, The University of Tokyo, National Institute of Polar Research, and National Institute for Environmental Studies.

The ability of atmospheric aerosol to absorb water (hygroscopicity) is a key property to understand the climatic effect of the aerosol, because it governs the role as nuclei in the formation of cloud droplets. In this study, for aerosols in Okinawa, the degree of the hygroscopicity of water soluble components and the contribution of inorganic and organics to the hygroscopicity were determined, and the composition related to the variation of the hygroscopicity was characterized. Further, the results from offline analyses, the analysis of atmospheric aerosol samples in a laboratory, were compared with those from observations at the study site; it showed the usefulness of the offline analyses for the study of the hygroscopicity of atmospheric aerosol. This study is expected to contribute to the understanding of the climatic effect of aerosols and the technical development for studies on this subject.

This study was published in Atmospheric Chemistry and Physics on May 2, 2022. The study was supported in part by JSPS under KAKENHI (JP19H04253 and JP18K19852) and the Environment Research and Technology Development Fund (JPMEERF20202003) of the Environmental Restoration and Conservation Agency of Japan, and was in part performed under the joint research program of ISEE.

Deng, Y., Fujinari, H., Yai, H., Shimada, K., Miyazaki, Y., Tachibana, E., Deshmukh, D. K., Kawamura, K., Nakayama, T., Tatsuta, S., Cai, M., Xu, H., Li, F., Tan, H., Ohata, S., Kondo, Y., Takami, A., Hatakeyama, S., and Mochida, M.: Offline analysis of the chemical composition and hygroscopicity of sub-micrometer aerosol at an Asian outflow receptor site and comparison with online measurements, Atmos. Chem. Phys., 22, 5515–5533, 2022. DOI:10.5194/acp-22-5515-2022