Research On The Environmental Effects Of Urban Spatial Structure

As China’s urban population surpassed its rural population for the first time in 2011,conflicts over social and environmental issues within cities intensified.In order to cope with this problem,China has carried out a large number of new city construction actions represented by the construction of Xiong’an New Area,aiming to optimize the effect of the environment by changing the monocentricity spatial structure of the city.It is particularly important to study the environmental effects of this emerging new city construction and provide policy suggestions for subsequent spatial structure transformation.This paper focuses on the impact of urban spatial structure change on environmental pollution and its transmission mechanism,aiming to find the type of urban spatial structure that is most conducive to improving the environment,providing suggestions for the development of urban spatial structure in the future,and helping to improve urban environmental quality.Based on the classical theory of urban spatial structure,this paper constructs a research model by analyzing and sorting out important literature on urban spatial structure and environmental pollution.Then,based on the panel data of 285 prefecturelevel cities in China from 2006 to 2020,this paper describes the spatial structure and environmental pollution characteristics of cities in China from the aspects of spatial distribution and temporal change trend,and analyzes the reasons that may lead to these characteristics.Finally,by using econometric models such as fixed-effect and 2SLS model,the environmental effects of urban spatial structure are empirically studied,and the robustness of the baseline regression results is proved by instrumental variable testing and substitution of explanatory variables,and the mechanism analysis and nonlinear relationship between spatial structure and environmental effects are further explored.Through the above research and analysis,the results obtained are as follows:(1)The relationship between urban spatial structure and environmental pollution in China is significantly positive,the PRI index increases by 1 percentage point,the AQI index will increase by 0.0486%,and the PM2.5 concentration will increase by 0.0544 percentage points,that is,the monocentricity degree of urban spatial structure will produce negative environmental effects.(2)The mechanism analysis shows that the increase of the unicentric index of urban spatial structure will act on environmental pollution through the three paths of private transportation,population agglomeration and natural purification,resulting in the increase of AQI index and PM2.5 concentration,and ultimately deterioration of environmental quality.(3)In terms of nonlinear analysis,the impact of urban spatial structure on the environment will vary with the degree of monocentricity,and this difference is manifested as a positive "U" shaped nonlinear relationship.