The GIS-Based Modeling Of Kaifeng Old City Zone Vehicle Emission Dispersion

In recent years, the transformation from the coal smoke pollution to the vehicle emission pollution is one of the most important characteristic of air pollution in china. Vehicle emission pollution in the urban road is one of the key factors for urban air pollution. The research about the dispersion of vehicle emission pollution under the influence of terrain, construction and weather is very important on urban air pollution analyzing and forecasting.Based on the well known research achievements, a case study of the old city zone of Kaifeng, the MOBILE6.2 model were amended. The vehicle emission evaluation model suitable for the old city zone of Kaifeng is built based on Gauss Model. At last the vehicle emission dispersion models and GIS(Geographic Information System)technique were integrated, a vehicle emission GIS software, which could display the distribution of pollutant concentrations arising from the vehicle emission was developed.The research includes the following three aspects:Firstly, start with the most basic parameter, emission factor which reflected vehicle emission status, using the MOBILE6.2 developed by the American EPA, revised the related vehicle situation parameter and the environment parameter according to the actual data in the old city zone of Kaifeng. The emendatory MOBILE model suitable for Kaifeng was established. The model was applied to vehicle emission factor simulation in Kaifeng.Secondly, the analytical solution of the equation under the condition of wind and continuous spot-source is given on the research of vehicle emission evaluation models, and the connection of the analytical solution with the spot-source Gauss Model was built. Based on the connection, the spot-source model was added by use of linear theory, and a common line-source model of vehicle emission dispersion was expressed. Compared with others, the common model was more applicable.Finally, through integrating the vehicle emission dispersion models (including the model with the wind and without wind) and GIS(Geographic Information System )technique, a vehicle emission GIS software, which could display the distribution of pollutant concentrations arising from the vehicle emission based on the real-time data of traffic condition and the velocity of wind was developed.The research indicates that the urban vehicle emission dispersion was influenced by the road-net obviously and the air pollution in the urban intersection was more serious. In addition, the vehicle emission GIS software could be used to analyze, evaluate and forecast the urban air pollution arising from the vehicle emission.