| Environmental problem is one of the most serious human society problems in the 21st century. Total amount control is an effective measure for environmental pollution comprehensive control, which the key process is making an exactly comprehensive evaluation for system present situation and calculating the environmental aimed value of total amount control.lt's well known that the environmental system is a typical grey system indicating that part of the information is clear, while another part is still unknown. It's a newly question for discussion problem which has obviously practical meaning to study the environmental total amount control with the grey system theories which is founded by Deng J.L in the 1980s.Single-index method is generally used in environmental quality evaluation in China, by which the whole situation is very difficult to be fully described in system. The linear whiteness function is used to calculate the real weight in the classical grey clustering model in which zero weight problems existed, so that the warped results are made. The exponential whiteness function was introduced into the modified model. Each value of certain factor is uniquely corresponding with each nonzero weight of various grades, so that the cumulated action mechanism and the zero weight problems are all solved. With the dataset of Guiyang's atmospheric environment in 2004, after comparison, the results from the modified model are more fit the fact than the result from the classical model in veracity.By using the modified model, comprehensive grade of Hangzhou atmospheric quality in 2004 is grade II, which attains this city's atmospheric quality standard.After comprehensive evaluation, the chief factor is next to be choosed by factor analysis. In grey system theory, factor analysis is made by grey relation analysis model in which the weight is considered equal when calculating the relation degree.Based on the classical grey relation analysis method, a changed weight method of various grades was introduced, and a relation analysis evaluation modification model was established. With the dataset of Hangzhou Economic & Technological Development Area's atmospheric environment in 2003, after comparison, the results from the modified model are more fit the fact than the result from the classical model and the weighed model in veracity. By using the modified relation model, PM10 is confirmed to be the chief pollutant of Hangzhou atmospheric environment in 2004 and SO2 is the most relationed factor for PM10.In practice of total amount control, it is important to make sure the aimed controlvalue of each factor. But the methods for calculation in present are generally single -index mode, which don't consider the influence of other indexes. Based on both the modified clustering model and GM (1,1) model, the concentration threshold model of each pollutant is established to calculate the critical value with the environment aim at attaining the standard grade. In this threshold model, firstly to predict the concentration of each index, then to calculate the comprehensive membership of each grade, last to work out the concentration threshold based on the adjustment of comprehensive membership. The influence between one index and others are realized with the adjustment of comprehensive membership. After prediction, the concentration of PMio in Hangzhou for the year 2005 is 0.11458 mg/m3, which is above the standard grade.By using the modified clustering model, the comprehensive grade of Hangzhou atmospheric environment quality is II. At last, the critical value of of pollutant PMio is 0.1227 mg/m , that's to say the aimed value of total amout control for pollutant PMio is 0.1227 mg/m3.
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