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NUMERICAL SIMULATION ON THE FORM AND DISTRIBUTION OF OZONE BY URBAN TRAFFIC EXHAUST EMISSION

A three dimensional photochemical model for urban boundary layer is set up.In order to provide a more accurate advection and turbulence process for the simulation of the distribution of the species,the simple energy(E e)closure scheme was used when we simulate the meteorological process in the three dimensional model.Traffic gas emissions,biogenic hydrocarbon emissions were considered as the procedure of the photochemical pollution.The distributions of the photochemical pollutants at different times and different places in both winter and summer in Nanjing city were simulated by the three dimensional photochemical model.It is showed that the concentrations of photochemical pollutants in summer are much higher than that in winter.In summer,there are many places in Nanjing city where high concentration of O 3 and PAN were found,those concentration are much higher than the national standards.In Nanjing,the pollution of PAN is more serious than that of O 3,because of the different wind directions at different seasons in Nanjing,there are different distributions of photochemical pollutants in the whole city at different seasons.The effect of wind on the distribution is more obvious at higher height.