Research On The Impact Of China’s Urbanization On Air Pollution Emissions

Although China’s rapid urbanization has provided a strong economic impetus,the negative environmental effects of rapid urbanization have gradually become prominent,with the contradiction between the quality of the air environment and urbanization gradually emerging.How to systematically recognize the evolution mechanism between urbanization development and atmospheric environmental quality changes has become one of the key issues facing the green,high-quality and sustainable development of Chinese cities.Facing with these problems,most of the existing studies have focused on a single region,and few have analysed pathways and transmission mechanisms,and few have studied development models that combine environmental protection of the atmosphere with high-quality urban development.In view of this,this paper examines the relationship between urbanization and air pollution emissions in terms of what influences it,how it affects it and when it changes,with a view to promoting air environment protection and green and sustainable urban development in parallel with rapid urbanization.The dissertation combines theoretical analysis with empirical tests,focusing on the impact of urbanization on air pollution emissions,conduction pathways and threshold effects.Firstly,based on the panel data model,the impact of urbanization on air pollution emissions in the whole country and the four economic circles of the Yangtze River Delta,the Pearl River Delta,the Bohai Rim and the Sichuan-Shaanxi-Chongqing was studied,answering the question of“whether there is an impact of urbanization on air pollution emissions?”and“whether there is spatial heterogeneity in this impact?”;Secondly,the EKC curve model was constructed based on the theory of environmental Kuznets curve（EKC curve）to empirically study the evolution of air pollution emissions in the urbanization process of the whole country and the four economic zones,and to answer the question of“whether there is a non-linear relationship between urbanization and air pollution emissions?”;Thirdly,by constructing a model of the mediating effects of energy consumption,industrial agglomeration and technological progress through stepwise testing of regression coefficients,the transmission mechanism of urbanization on air pollution emissions in the country and the four major economic zones was empirically studied,answering the question of"in what way does urbanization affect air pollution emissions?";Finally,by using a variable intercept panel threshold model,the threshold effect of urbanization on air pollution emissions was empirically analysed from three perspectives,namely energy consumption,industrial agglomeration and technological progress,answering the question of“when does the impact of urbanization on air pollution emissions change?”.The dissertation consists of eight chapters:The first chapter is the introduction,which expounds the research background and significance,and puts forward the research innovations and deficiencies of this paper on the basis of relevant literature.The second chapter is the theoretical basis and research hypothesis,mainly including the theoretical basis of urbanization affecting air pollution emissions and the theoretical hypothesis of the coordinated development of urbanization and air pollution emissions differentiation proposed in this paper.The third chapter is about the temporal and spatial distribution characteristics of China’s air pollution emissions,and compares and analyzes the SO₂and particulate matter emissions across the country and the four major economic circles from 2004 to 2019.The fourth chapter is the research on the impact of urbanization on air pollution emissions.Through the panel data model,it empirically analyzes the impact of the urbanization process of the country and the four major economic circles on air pollution emissions.On the basis of the fourth chapter,the fifth chapter carries out the EKC curve test of the impact of urbanization on air pollution emissions,builds a model based on the EKC curve theory,and empirically studies the evolution of air pollution emissions in the process of urbanization in the country and the four major economic zones.The sixth chapter is the research on the transmission mechanism of the impact of urbanization on air pollution emissions.By constructing a mediating effect model,the dissertation empirically investigates whether the variables of energy consumption,industrial agglomeration and technological progress in the country and the four major economic circles are mediating variables of the impact of urbanization on air pollution emissions and to what extent the mediating effect can be exerted.The seventh chapter is the threshold effect analysis of the mechanism of urbanization on air pollution emission.Using the variable intercept panel threshold model,three transmission paths of energy consumption,industrial agglomeration,and technological progress are selected to analyze the threshold effect of urbanization on air pollution emissions,and the threshold effect of these three variables is empirically analyzed.The eighth chapter is the conclusion and recommendations.Based on the previous theoretical analysis and empirical test,the conclusions of this paper are summarized and relevant suggestions are put forward.The core conclusions of the paper include:Firstly,China is in the stage of urbanization suppressing air pollution emissions,and air pollution emissions show an inverted"U-shaped"curve with the increase of population urbanization rate.At present,the national average population urbanization rate is at the inflection point of the curve.The right end has entered a stage of improvement.Secondly,urbanization can affect air pollution emissions through three paths of energy consumption,industrial agglomeration and technological progress,of which technological progress is the most important path and also plays a role in regulating variables.Thirdly,there is a threshold effect for the three pathway variables,and the impact of urbanization on air pollution emissions will change within different thresholds.Fourthly,there is spatial heterogeneity in the impact of urbanization on air pollution emissions.The Yangtze River Delta and Sichuan-Shaanxi-Chongqing regions are in the stage of urbanization intensifying air pollution emissions,while the Pearl River Delta and Bohai Rim regions are in the stage of urbanization suppressing air pollution emissions.In the Yangtze River Delta and the Pearl River Delta,the relationship between air pollution emissions and urbanization is a"U"-shaped curve,while in the Bohai Rim and Sichuan-Shaanxi-Chongqing regions,the relationship between air pollution emissions and urbanization is an inverted"U"-shaped curve.Fifthly,the conduction mechanism of urbanization affecting air pollution emissions also has spatial heterogeneity.Energy consumption has different degrees of conduction in the Pearl River Delta,Bohai Rim and Sichuan-Shaanxi-Chongqing regions,and plays a major role in transmission in the Pearl River Delta region;Industrial agglomeration in the Yangtze River Delta,Pearl River Delta and Sichuan-Shaanxi-Chongqing regions has different degrees of conduction role,among which in the Sichuan-Shaanxi-Chongqing region,it plays a major conduction role;technological progress has different degrees of conduction in the Yangtze River Delta and Bohai Rim regions,and all of them have a major conduction role.The core innovations of the paper include:Firstly,on the basis of previous research,this paper puts forward the theoretical hypothesis of the coordinated development of urbanization and air pollution emissions,and systematically demonstrates the coordinated development mechanism of urbanization development and air pollution emissions,and the reasons for differentiation.Secondly,the mediation effect model was used to quantitatively analyze the transmission mechanism and spatial heterogeneity of the three variables of energy consumption,industrial agglomeration and technological progress as transmission paths between urbanization and air pollution emissions.The threshold effect analysis of the three mediating variables was carried out,and the threshold value of the mediating variables was determined.Thirdly,the spatial heterogeneity of the relationship curve between urbanization process and air pollution emission and the transmission mechanism are investigated in depth to find out the reasons for the spatial heterogeneity of the transmission mechanism.At the same time,the reasons for the spatial heterogeneity of the relationship curves between urbanization process and air pollution emissions were investigated,which provide ideas for the sustainable development of cities in different regions.