Original Articles
Yan Yan, Yingna Zhao, Guanchen
Abstract
The boundary of good or bad and the grade division of ambient air quality is blurring. Through the collection of the content of main air pollutants in 7 cities such as Beijing, Shanghai, pollutant indicators that mainly affect air quality are determined. Combining with national air quality standard, urban air quality is graded by using of fuzzy comprehensive evaluation theory. It can be concluded that air quality is excellent in Wu Xi, good in Cheng Du, Wu Han and Shanghai, qualified in Nan Jing, while contaminated in Chong Qing, and only in Beijing the air quality is severely polluted. Through cluster analysis of more than 30 cities by using K-means clustering, the seven cities are classified into 5 categories, which is basically consistent with the results of fuzzy evaluation, proving the accuracy of fuzzy evaluation theory. In weight determination by using fuzzy comprehensive evaluation, only one indicator is involved in, but some other relations are not considered, therefore, entropy weight method is introduced in weight coefficient determination to reevaluate air quality grades of the seven cities.