Research On Vehicle Exhaust Pollution In Shanghai City Under The GIS Environment

In recent years, the atmospheric pollution has been gradually more serious, which is transforming from coal-based pollution into traffic-based pollution. The number of motor vehicles in our whole country, especially in such metropolitan cities as Beijing, Shanghai and Guangzhou, increases rapidly. Furthermore, the emission level of vehicles made in China is tens or even hundreds times of that in the United States and Japan. The improvement and maintenance of vehicles are not quite good, urban traffic is very crowded and the population density is quite high, which deteriorate the urban air quality. Therefore, it is quite necessary to calculate the emission amount of vehicle exhaust pollutants and analyze its variation with time, vehicle types and area. Moreover, we applied an advanced line source dispersion model into the analysis of traffic pollutants distribution, by using the urban road net, geographic environment, traffic volume and meteorological conditions provided by GIS. All of the work is of great value as a basis for government to establish environment management system, urban planning and construction management.Firstly, we made a large-scale research and sampling on Shanghai traffic condition, based on which the inventory of vehicle type ratios, vehicle miles traveled and vehicle speeds were set up. Emission factor is a key parameter in the calculation of vehicle pollutants emission amount and emission rate. It directly influences the veracity of calculation results. In this research, we selected the MOBILE6 mobile source emission factor model provided by US EPA to calculate the vehicle emission factors, which were further modified according to the emission factors test data and Shanghai current situation. Thus, the inventory of emission factors was built up. Based on these inventories, we launched researches on Shanghai vehicle pollutants emission in two ways: macro-scale and micro-scale.In macro-scale research, we calculated the total emission amount according to areas, vehicle types and different years. Thus, we can get the emission difference with years, vehicle types and areas. The whole Shanghai city is divided into five sub-areas: region which lies to the west of Huangpu River and within inner-ring road; region which lies to the east of Huangpu River and within inner-ring road; region which liesto the west of Huangpu River and between the inner-ring road and outer-ring road; region which lies to the east of Huangpu River and within inner-ring road and region which lies outside the outer-ring road. All vehicles in Shanghai are divided into seven types: Light-duty gasoline vehicle, Medium-duty gasoline vehicle, Medium-duty diesel vehicle, Heavy-duty gasoline vehicle, Heavy-duty diesel vehicle, Motorcycle and Light duty motorcycle. The research time includes base year 2000, current year 2002 and future years of 2005,2010 and 2020.In micro-scale research, we calculated the line source emission rate of typical roads in Shanghai, from which we can learn the pollution situation of roads. We calculated emission amount of pollutants at 21 typical intersections base on survey of the vehicle flow, vehicle type ratio and vehicle speed. The dispersion situation along typical roads was simulated using the line source dispersion model-CALINE4, developed by California traffic department and recommended by USEPA.Base on the above researches, a Shanghai Traffic Pollution Management System was developed using Visual Basic 6.0 programming language and MapObjects 2.1. This system integrates all these functions and can display the modeling results on Shanghai traffic map. It also provides the comparison of vehicle exhaust control measures between China and other countries, which is a theoretical basis for government to set up traffic pollution management regulation and urban planning.