构建了城市规模-环境质量理论模型,然后利用变截距模型对我国1997~2006年的面板数据进行分析。结果显示:我国的城市规模-环境质量经验模型为正N形曲线,两转折点对应的城市规模分别为260万人和930万人。由经验模型得到以下结论:有利于城市环境质量提高的最优城市规模为260万人,适度城市规模是200~350万人。 中国的城市规模与环境质量之间并没有表现出理论模型所分析的倒N型曲线关系;一方面说明中国的城市化有其自身的特殊性,另一方面也说明理论模型具有一定局限性,其进一步完善还需要更多实证研究的支持。

Pursuing an ideal urban living environment of mankind is the common goal of human beings. On the one hand, the urban aggregation effect not only leads to an expansion of the city scale, but also causes a concentration of various production and life pollutants, and urban environment quality deterioration. What city size is suitable for the improvement of environment quality, is a question needed to be discussed deeply. Through constructing a theoretical model of urban scale-environment quality, this paper analyzes the panel data of China during 1997~2006 based on the variable-intercept model. The results are shown as follows: the empirical model of city scale-environment quality in China presents a positive N-shaped curve, the corresponding city scales of the two turning points of the curve are 2.6 and 9.3 million. According to the empirical model, the optimal city scale is 2.6 million, and the reasonable city scale is between 2~3.5 million. Apart from some provincial capital cities and all of the cities at prefecture level and above, the majority of the cities in China are in a rising stage of environment quality, and the expanding of city scale is favorable to the sustainable utilization of urban environment. In order to alleviate the constraint of urban environment to sustainable development, environment-friendly development in the process of urbanization is called for by the severe situation in current China. From the empirical model, the result indicates that the city scale-environment quality in China did not show an inverted N-shaped curve concluded by the theoretical model. On the one hand, it is revealed that the specificity of China's urbanization, on the other hand, there is still certain limitation in the theoretical model. So the improvement of the theoretical model needs further support by more empirical research.