In this study, we used Offline Scale-Chem [2], an offline coupled meteorological model [3][4] and chemical transport model [5][6]. The initial and boundary conditions were obtained from MANL and the calculation period was from 201910010000 to 11010000. We calculated the contribution of below-cloud scavenging (washout). It is revealed that a higher contribution of the total wet deposition was due to the washout process for nitrate than for sulfate. The averaged washout contribution was 59.7% for sulfate and 74.1% for nitrate. The analysis of the contribution of the washout process to the change in the average of PM2.5 concentrations showed that the amount of change in PM2.5 concentrations was -4.28 μg/m3, quantitatively indicating that the washout process contributed to the reduction of PM2.5 concentrations. The present results suggest that the deposition processes are effective in reducing PM2.5 concentration.
[1] Fujino and Miyamoto, 2022. [2] Nakata et al., 2021. [3] Nishizawa et al., 2015. [4] Sato et al., 2015. [5] Kajino et al., 2019. [6] Kajino et al.,2021.

