2018 Volume 53 Issue 3 Pages 88-99
The Community Multiscale Air Quality Model (CMAQ) was used to estimate the contributions of long-range transport (LRT) from the Asian Continent to Japan, domestic emissions in Japan, and background sources including boundary inflow and natural emissions to the concentrations of nitrate aerosols and its precursor compounds (NH3, HNO3, NO2) in four major Japanese urban areas in fiscal year 2010. The estimated LRT, domestic and background contributions to the PM2.5 concentration in Japan were 32–54%, 18–37% and 28–31%, respectively. The estimated LRT contribution to the PM2.5 was generally higher in the western areas of Japan (closer to the continent). The contribution of the LRT was classified into the direct LRT contribution and indirect LRT one representing the PM2.5 produced from the domestic and transported precursor compounds. The indirect LRT contributions in each area were dominated by NH4NO3 and had no significant difference in the rate and the total amount of chemical components. Moreover, the formation of domestic nitrate aerosol was affected by the domestic NH3 and overseas HNO3, according to the results of source contributions of precursor compounds. The indirect LRT contribution can be reduced by controlling the NH3 emissions in Japan.
