Research On The Impact Of Manufacturing Agglomeration On Air Pollution

With the increasingly serious air pollution problem in China,energy conservation and emission reduction have become an important content of China’s sustainable development strategy,and the positive and negative environmental externalities brought about by industrial agglomeration have increasingly attracted attention from scholars at home and abroad.On this basis,exploring the impact of manufacturing agglomeration on air pollution and spatial spillovers will provide a scientific basis for joint prevention and control of pollution among regions,and provide a reference for alleviating the current contradiction between economic development and environmental protection.Firstly,based on a systematic review of existing literature,this paper decomposes the impact of manufacturing agglomeration on environmental pollution into scale effects,technological effects,and structural effects,clarifying the theoretical mechanism of manufacturing agglomeration affecting environmental pollution;Secondly,the temporal and spatial evolution characteristics of manufacturing agglomeration and air pollution in prefecture-level cities were analyzed using Arc GIS 10.7 software;Thirdly,using panel data from 284 prefecture-level cities from 2007 to 2019 as the research sample,PM2.5concentration in each city as the explanatory variable,and manufacturing agglomeration level calculated by location entropy as the core explanatory variable,a general panel model is constructed to preliminarily test the inhibitory effect of manufacturing agglomeration on air pollution;Finally,on the basis of testing the spatial autocorrelation between manufacturing agglomeration and air pollution,a spatial panel model and various spatial weight matrices are set up,and the maximum likelihood estimation method is used to estimate the spatial panel model.The robustness of the model is tested by adding lag explanatory variables,adding missing variables,replacing weight matrices,and time-phased regression.Through the above research,this article draws the following conclusions:(1)The degree of agglomeration of China’s manufacturing industry has further strengthened over time,and its spatial distribution presents significant agglomeration characteristics around the five major urban agglomerations,namely,the Beijing Tianjin Hebei urban agglomeration,the Yangtze River Delta urban agglomeration,the Pearl River Delta urban agglomeration,the middle reaches of the Yangtze River urban agglomeration,and the Chengdu Chongqing urban agglomeration.PM2.5 pollution focuses on the BeijingTianjin-Hebei urban agglomeration and its surrounding areas such as Henan Province and Shandong Province,with PM2.5 concentrations gradually decreasing outward around the core area.In the central and western regions,the Chengdu-Chongqing urban agglomeration is the concentration area of PM2.5 pollution.(2)Without considering spatial effects,deepening the degree of manufacturing agglomeration can help improve the quality of the urban environment.After analyzing the heterogeneity of eastern,central,and western regions,it is found that manufacturing agglomeration in the eastern region has a significant improvement effect on environmental quality.After analyzing the heterogeneity by city size,it is found that manufacturing agglomeration in large and medium-sized cities can significantly suppress the level of air pollution.(3)The spatial Dubin model regression results based on different weight matrix settings show that the spatial autoregressive coefficient of air pollution is significantly positive,indicating that there is a significant spatial spillover effect of air pollution in prefecture-level cities in China,that is,local air pollution can cause environmental quality deterioration in neighboring areas through geographical and economic factors.The direct and indirect effects of manufacturing agglomeration on air pollution in prefecture-level cities in China are significantly negative,that is,deepening the degree of manufacturing agglomeration can significantly improve local and neighboring air pollution levels.The robustness test found that the above research conclusions are still valid whether it is to delay the explanatory variables by one period,add missing variables such as environmental regulations and natural climate factors,or replace the spatial weight matrix.