Air Quality Assessment Of Main Cities Along Yangtze River Based On Grey Cluster And Fuzzy Comprehensive Evaluation

As the process of the industrialized accelerating, the urban economy developing rapidly and the dimensions expanding ceaselessly, the industrial production and human life emit large amounts of pollutants which lead to the air pollution and the air quality decrease. However the air is one of the important elements of human life. What's more, air quality has a direct and long-term impact on the human health, ecological balance and the social security. So it becomes the focus of how to maintain the clean air and realize the harmonious development among the urban economy, the society and the environment. The air quality evaluation theory is used to assess the urban air quality, determine its level and find out the main factors. Additionally it can put forward reasonable suggestions and prevent measures to provide a direction on controlling urban industrial pollution and protecting the air environment. As a result, it can provide a scientific basis for urban planning and environmental management.The economic belt of Yangtze River composed mainly of coastal urban agglomeration, which is one of the high economic density, potential growth and strengthened development areas in China. Eleven major cities from the upstream, midstream and downstream of Yangtze River were chosen as strong representation of the west, middle and east city group of China. On the basis of the theory of grey system and fuzzy mathematics, the classical grey clustering model and the fuzzy comprehensive evaluation method, improved grey cluster model and fuzzy comprehensive evaluation method were constructed with exponential whitening function and exponential membership function used and the weight of evaluation indexes determined by the weight of standard index and actual index. An analysis and a sort of the air qualities of the chosen cities were made combined with the use of SPSS software. And then according to their qualities, the levels were classified. At the end, the grey prediction model (GM) was used to predict the air pollution concentration in the future ten years of Chongqing that was the most polluted. The results were as follows:1)The evaluation results was indicated that the primary pollutant of the Yangtze River city group was PM10;2004to2010the proportion of SO2pollution was in decline and NO2pollution was in rise. NO2gradually replaced SO2to become secondary pollutants, consequently, air pollution gradually transformed from coal smoke pollution into a complex mix of pollution. NO2emission and pollution control need be highly valued. The air quality between the2004and2010was showed a rise trend, and the ranking were as follows:1-Wuhu,2-Ma'anshan,3-Jingzhou,4-Shanghai,5-Yichang,6-Jiujiang,7-Wuxi,8-Wuxi,9-Nanjing,10-Chengdu and11-Chongqing.2) The two evaluation methods were obtained the same results. The eleven cities can be divided into three categories:Wuhu,Ma'anshan,Jingzhou and Shanghai was the first type that the air quality was better; Yichang, Jiujiang,Wuhan were the second type that the air quality was middle; Nanjing,Wuxi,Chengdu and Chongqing wad the third type that the air quality was worse.3)The prediction results of Chongqing city revealed that, the air pollutants concentration was in a declining trend and the air quality was gradually improved. Those was consistent with the annual variation of the sample data and the actual condition. Consequently, it means that the air pollution has been controlled with the influence of various environmental protection measures in recent years.4)Based on the evaluation results, some measures to improve the air quality could be put forwards as follows:controlling pollution from the pollution source, adjusting the industrial layout, optimizing industrial structure, strictly controlling high energy consumption and high pollution projects; developing the recycling economy, promoting clean industry to replace the traditional industry, Strictly enforcing "energy conservation and emission reduction", total amount control and other environmental protection measures; strengthening the environmental education to the public, improving people's environmental awareness.