2011 Volume 46 Issue 2 Pages 101-110
A three-dimensional air quality simulation was conducted to analyze the sensitivities of the emission sources and transboundary transport on PM2.5 concentrations in three major Japanese urban areas for the year 2005. The sensitivities of the emission sources were derived from the differences in the concentrations in two simulation cases in which the emissions of the respective sources were absent or used. The sensitivity of the foreign anthropogenic sources was high in the Osaka-Hyogo area, but those of the domestic sources including volcanoes, ships, vehicle exhausts, other combustions and NH3 were higher in 23 Tokyo wards. The seasonal meteorological conditions caused higher sensitivities of volcanoes and ships in summer, foreign anthropogenic sources in spring and autumn, and domestic sources in winter of the Shuto area and 23 Tokyo wards. The sensitivities of volcanoes, ships, and foreign anthropogenic sources to SO42-, vehicle exhausts and other combustion sources to NO3-, NH4+, EC and primary organic aerosols (POA), and biogenic and VOC evaporative sources to secondary organic aerosols (SOA) were evident. The NH3 sources had high and nonlinear sensitivities to NO3- and NH4+. However, PM2.5 concentrations were underestimated in the current simulation by 30-40% for the entire year. The underestimated EC and OC may be the main causes for the PM2.5 underestimation. The sensitivities of the sources which influence EC and OC in the real atmosphere were inevitably underestimated in this study.
