PM13 Watershed/Airshed Science and Regulation
Exhibit Hall
8:00 AM - Monday, 10 November 2003
(PM196) Source apportionment based on atmospheric dispersion model and multiple regression analysis.
Fushimi, A1, Kawashima, H2, Kajihara, H3, Nakanishi, J2, 4, 1 National Institute for Environmental Studies, Tsukuba, Japan2 Yokohama National University, Yokohama, Japan3 Niigata University, Niigata, Japan4 Research Institute for Industry and Technology, Tsukuba, Japan
ABSTRACT- It is important to determine the contribution of each emission source to ambient concentrations in order to establish effective risk reduction measures against air pollutants. For some automobile-dominated air pollutants such as benzene, factories as well as automobiles seem to greatly affect the ambient concentrations near industrial complexes. Source contributions can be estimated by using emission amounts and a simulation model. Although the Pollutant Release and Transfer Register (PRTR) system was implemented in 2001 in Japan, the validity of the PRTR emission data is not yet verified. In contrast, source contributions can be estimated from ambient concentrations without emission amounts, but most existing methods require source profiles (emission amount ratios of multiple chemicals). We have developed a method which estimates each source contribution on the basis of ambient concentrations of a target chemical without emission amounts or source profiles. Our method is based on multiple regression analysis using measured concentrations and concentrations calculated by a dispersion model that assumes unit emission by each source. The method was applied to benzene in the vicinity of the Keiyo coastal industrial complex, one of the biggest industrial complexes in Japan. Benzene concentrations were measured at 31 sites simultaneously and at three sites continuously in the complex and the nearby residential area from March 2001 to July 2002. On the basis of the measured data and the method we have developed, we estimated benzene emission and the contribution of each factory and road. Estimated contributions of the industrial complex to the ambient concentrations in some parts of the residential area exceeded 70% on an annual average basis. The estimated concentrations agreed well with the measured values, showing that our method is reasonable.
Key words: source apportionment, air pollutants, dispersion model, multiple regression analysis