Abstract

Despite low concentrations of aerosols and precursors of surface ozone in Japan compared with other countries in East Asia, concentrations of surface ozone there are yearly increasing and endangering the environment. The aim of this study was to examine whether transboundary air pollution from neighboring countries such as China could be associated with this increase or not. Data on the 1–hr daytime and maximum–hr concentrations of surface ozone were obtained from 1,183 monitors distributed in 47 prefectures. Annual means of these concentrations were calculated for all districts that are located along the Sea of Japan since these districts are the first receptors of transboundary air pollution from neighboring countries. We found that the annual mean of the 1–hr daytime and maximum–hr concentrations of surface ozone are positively associated with the annual increase of the industrial waste gas emissions in China from 2000 to 2009. This finding suggests that the industrial emissions from China could be associated with the annual increase surface ozone concentrations in Japan. However, limited spatiotemporal information about the emissions of surface ozone and its precursors in China makes it hard to quantify the contribution percentage.