Study On The Evaluation And Forecasting Models Of Atmospheric Environment Quality In Hefei City

In the last years, with the development of social economy and modern industry, the environment of city becomes more and more serious. Air pollution is one of problems, which are motioned by more and more people. In order to control air pollution efficiently, we should make scientific assessment and forecasting of air quality. This paper will study the evaluation methods and forecasting models of air quality based on the conventional research.Selecting SO₂, NO₂, PM₁₀ as evaluation factors, the atmospheric environment quality of Hefei city was evaluated by applying the methods of Fuzzy comprehensive judgment, gray correlation analyzing and the air quality evaluation aided by GIS. The result of each method can reflect the actual pollution accurately. The evaluation method aided by GIS has breakthrough essentially, and on the basis of the GIS functions of spatial data analysis and attribute inquiring, the atmosphere quality is analysed using multi-factors compound method. Weight values of urban atmosphere pollution factor are evaluated by district difference and pollution contribution. The result can describe the space distribution regulation of each pollution factor and the environment quality variety regulation between districts precisely.Some atmospheric pollution concentrations have been calculated by using a complex model of Gauss model and multi-dimensional multi-box model. The multi-dimensional multi-box model can calculate the pollution density of the area sources very availably on the basis of considering physical and chemical removal mechanisms and wind-direction variations. The Gauss model is applicable to calculate the pollution density of the point sources. So the complex model can predict the whole pollution concentrations of the study area accurately. Compared with the ground monitoring data, the results gained from using the complex model accorded with the ground monitoring data. Therefore the testing results can prove that the complex model is effective and useful for its targeted application.The selection of the parameters is very important. This paper will study the selection of each parameter according to the actual circumstance in Hefei city. The values of mixed heights, the wind velocity profile exponent and each parameter of Gauss distribution model are selected by national standard. The vertical diffusion coefficient is selected with the recommending method by the environment science Center of Peking University, and the horizonal diffusion coefficient is decuple the vertical diffusion coefficient. The results show that the selection of the parameters is reasonable.