With the softwares of Excel and Spss and statistical datum of 1989—2003, various mathematical functional models are applied to simulate the EKC (Environmental Kuznets Curve) of industrial waste gas discharge in Xi′an, then the best one is selected. The curve reveals the dynamic evolving trace of environmental economy situation of Xi′an′s industrial development in the recent 15 years, and reasons of variation are analyzed, by means of factor analysis and correlation analysis of grey-system. Results indicate that the Kuznets Curve of industrial waste gas discharge doesn′t match to a conversed “U” type, but presents “N” type. The industrial waste gas increases with the improvement of economic value, but decreases with the progress of technique and enhancement of the crossed synergy of economy and environment. These three factors conjointly cause the variation of the industrial waste gas in 1989-2003. However, compared with technological progress, the effects of the crossed synergy of economy and technology are more remarkable and obvious to the decrease of industrial waste gas. The degree of cross linking between the consumption of industrial raw coal and the discharge of the industrial waste gas is the highest, while the degree of cross linking between the investment of waste gas management and the discharge of the industrial waste gas is the lowest. Therefore, improving the quality of coal and using clean energy are the critical measures to restrain the increase trend of air pollution of Xi′an.

Xi′an city; industrial waste gas discharge; factor analysis; correlation analysis of grey-system