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Numerical Analysis of the Behavior of Photochemical Products in Local Flows Over Central Japan in Summer Season: Sensitivity of Ozone Concentration to Emission Sources Over Coastal Urban Areas

Toshihiro Kitada, Department of Ecological Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, 441-8580, Japan and Kiyoshi Okamura, Department of Environmental Information, Nagoya Sangyo University, Arai-machi, Owari Asahi, 488-8711, Japan.

Air pollution transport over Central Japan was numerically simulated in a typical land and sea breeze situation in summer season. The CTM used in the calculation were extensions of those described in Carmichael et al. (1986), Kitada et al. (1993), and Kitada et al. (2003), while meteorological fields including eddy diffusivity were calculated using a meso-scale meteorological model with k- turbulence model. Calculated results were compared with air-borne observation as well as surface observation Sensitivity of the production of ozone and acidic species to emissions of biogenic non-methane-hydrocarbon (NMHC), and anthropogenic-NMHC and -NOx were focused; the ozone, sulfate, and nitrate are chemically produced in pollutants-rich air mass migrating from coastal big cities to the central mountains. Some of the obtained results are as follows: (1) biogenic hydrocarbons could increase daily maximum ozone concentration as much as 20 ppb over the Nohbi and Kanto Plains, and (2) reduction of NOx emission by 20% may result in increase of the ozone concentration from a few to almost 20 % over the Nohbi Plain, indicating necessity of careful emission control. In addition, characteristics of ozone concentration observed at a mountainous site for 2007 will be discussed.