Size-segregated sulfate on top of Mt. Fuji transported from Sakurajima volcano eruption2013 · Size-segregated aerosol samples were collected on Mt. Fuji with a cascade impactor during daytime and nighttime. We analyzed for their ionic and element compositions. Samples were collected from 29 July to 2 August (first period) and from 19 to 21 August 2013 (second period). Based on combined chemical components and CMAQ, in the first period, the air masses had been transported from East Asia. In the second period, the Sakurajima volcano eruption had been transported. NH4+, SO42–and elements were the major ions in 2.5 < Dp ≤ 10 during the second period. The slope of a linear regression of non-sea-salt (nss)-SO42– versus NH4+ was nearly unity, particularly during the first period. However, nss-SO42– in coarse aerosol was shifted in great excess in the second period. We have observed a rare phenomenon in which sulfate shifts to 2.5 < Dp ≤ 10. Although the formation process of (NH4)2SO4 in coarse particle is hypothesized two mechanisms, we hypothesize the third mechanism in this study. Currently, radiative forcing is being discussed for the detection of volcanic aerosols using satellites with particle sizes of 1.2 µm. If this can be clarified, it will improve the reproducibility of sulfate radiative forcing.
