Research On The Impact Path And Countermeasures Of Polycentric Development On Haze Pollution In National Urban Agglomeration

In recent years,China’s economic aggregate has grown rapidly with the expansion of the city scale,but the rapid economic growth has brought about serious environmental pollution problems,especially the frequent haze pollution has attracted continuous attention from the public,scholars and the government.So,what kind of spatial structure is more conducive to reducing haze pollution in China’s national urban agglomeration?This paper takes 11 national-level urban agglomerations as the research objects.First,by using the urban agglomeration spatial structure measurement method to measure the spatial structure of urban agglomerations from 2000 to 2020,the spatial structure of national-level urban agglomerations is defined.Generalized spatial two-stage least squares(GS2SLS)was used to study the influence of the multi-center spatial development of national-level urban agglomerations on the haze pollution of urban agglomerations;the mediation effect model was used again to clarify the main ways of the impact of the multi-center spatial development of national-level urban agglomerations on haze pollution,and through further analysis and discussion,the restrictive conditions of the haze reduction mechanism for the multi-center spatial development of national-level urban agglomerations are clarified.Finally,corresponding countermeasures and suggestions for the haze management of national-level urban agglomerations were provided according to the research results.This study made the following findings:(1)The national urban agglomerations present a polycentric spatial structure as a whole,of which the Beibu Gulf Urban Agglomeration and the Lanxi Urban Agglomeration present a single-center spatial structure,and the other 9 urban agglomerations still present a polycentric spatial structure.(2)There is a spillover effect of haze pollution in national urban agglomerations,and the polycentric spatial development of national urban agglomerations is indeed conducive to reducing haze pollution.For every 0.01 unit increase in the degree of centrality,the haze pollution in urban agglomerations will be reduced by 0.301%-0.393%.In addition,when the population density of urban agglomerations exceeds 2510 people per square kilometer,the polycentric spatial development of urban agglomerations will aggravated haze pollution of urban agglomerations.(3)There is also regional heterogeneity in the haze-reducing effect of polycentric spatial development,which gradually weakens from east to west.For each0.01 unit increase in the centrality of urban agglomerations in the eastern,central and western regions,haze pollution will be reduced by 0.408%,0.393% and 0.121%,respectively.(4)The influence mechanism of polycentric spatial development of urban agglomeration on haze pollution is mainly reflected in three aspects,that is,polycentric spatial development of urban agglomerations can indirectly reduce haze pollution by increasing factor mobility,improving energy efficiency,and reducing the proportion of secondary industries.(5)The influence mechanism of polycentric spatial development of urban agglomeration on haze pollution will be affected by industrial agglomeration,the level of infrastructure and the distance between cities.Only when infrastructure and industrial agglomeration are at a high level,the haze-reducing mechanism of polycentric spatial development of urban agglomerations can be effectively exerted.In addition,the deviation effect of polycentric spatial development of urban agglomerations on haze pollution is n-shaped with distance,so haze pollution can be suppressed by rationally arranging the distribution of cities in urban agglomerations.According to the research results,the control of haze pollution in national urban agglomerations can be considered from the following aspects.First of all,in order to reduce the haze pollution of urban agglomerations,it is necessary to actively build a polycentric network of urban agglomerations,and make overall plans for the population distribution of urban agglomerations so as to give full play to the adjustment effect of population density.Secondly,urban agglomerations in the central and eastern regions should beware of the spillover of haze pollution and establish a mechanism to jointly prevent and control haze.Although there is no pollution spillover,urban agglomerations in the western regions should also build up a sense of urgency.Third,the formation of haze pollution is the result of a combination of various factors,so it is necessary to make overall planning,formulate scientific policies to reduce haze and implement haze-reducing targets at all levels.Finally,the exertion of the haze-reducing mechanism depends on higher levels of industrial agglomeration and infrastructure conditions,so the governments of non-central cities should be urged to actively carry out their functions,and the governments of central cities should continue to strengthen the dominant position,thereby promoting the flow of factors and improving the level of industrial agglomeration and infrastructure.