Study On The Effect Of Vehicle Exhaust On Visibility Based On CALPUFF Model Of Hangzhou

Haze happened frequently in recent years in Hangzhou. Due to the continued growth of vehicle number, air quality and visibility became more serious. Thus, it’s important to estimate the effect of the impact of motor vehicle on visibility and seek the correlation between them in order to realize the "blue sky" goal with higher visibility and less haze eventually.This study mainly analyzed the feature of visibility in Hangzhou urban area to understand the meteorological and pollutant emission variation and explore their correlation with visibility. Then the impact of motor vehicle on visibility was evaluated with the foundation of vehicle emission inventory of NOx and PM10by CALPUFF model, including the contribution of various extinction components to visibility. Then several abatement scenarios were established to predict the impact of vehicle increase on visibility.The results showed that haze was serious in Hangzhou and visibility presented with spatial and seasonal distribution which was not very high overall. Motor vehicles excepting meteorological factors were mainly associated with visibility decline with the contribution of50%～60%. PM2.5and NOx from motor vehicle were important factors affecting visibility. At the same time, visibility will reduce with vehicle number increasing year by year which will drop to11.4km in2015. While, visibility will has a little increase by enhancing emission standards and eliminating vehicles with high emission and a big increase by improving oil quality and interviewing alternative energy which will rise to30.4km,30.7km respectively.