Effects of Heat Intensity and Inflow Wind on the Reactive Pollution Dispersion in Urban Street Canyon

This paper investigates the impacts of heating intensity and inflow wind speed on the characteristics of reactive pollutant dispersion in street canyons using the computational fluid dynamic(CFD)model that includes the transportation of NO,NO_2,and O_3coupled with NO-NO_2-O_3photochemistry.The results indicated that the heat intensity and inflow wind speed have a significant influence on the flow field,temperature field and the characteristics of reactive pollutant dispersion in and above the street canyon.With the street canyon bottom heating intensity increasing,NO,NO_2and O_3concentrations in street canyon are decreased.The O_3concentration reductions are even more than the NO and NO_2concentrations.Improving the inflow wind speed can significantly reduce the NO and NO_2concentrations within street canyons.But the O_3concentrations have a slight rise with wind speed increasing.The results would be useful for understanding the interrelation among reactive vehicle emissions,and provide references for urban planners.