Sensitivity Analysis of Primary Pollutants on Generating Photochemical Oxidants over the Osaka Bay and its Surrounding Areas of Japan

[摘要] In this paper an attempt has been made to elucidate the relationship between the formation of photochemical oxidants and the emission rate of the primary pollutants such as nitrogen oxides (NOX) and reactive hydrocarbons (RH) over the Osaka Bay and its surrounding areas of Japan, by using a three-dimensional grid model. In Harima area, reduction in the primary pollutant emission led to simple decrease in the peak O3 concentration, and OH and HO2 radical concentrations. In Osaka area, unlike the Harima area, reduction in NOX emission led to an increase in OH and HO2 radicals concentrations, and conversely to an increase in O3 concentration. It has also been found that the time of peak O3 concentration would appear earlier with reduction in NOX emission, and later with reduction in RH emission. Under meteorological calm condition, the variations of the time of appearance of peak O3 due to the emissions reduction scenario are small. Sea breeze may be one of the important meteorological phenomena responsible for the transport of pollutants such as NOX, RH, and also O3 in the polluted coastal areas. These important results suggest that a method for a well-balanced reduction in both NOX and RH emissions is essential for the improvement of air quality from photochemical pollution over the Osaka Bay and its surrounding areas of Japan.

[学科分类] 大气科学