The Impact Of Agglomeration On The Industrial Pollution Discharge

Agglomeration is one of the most important organizational forms of China’s industrial development.Especially along the Yangtze River Economic Belt（YREB）,an important economic leading demonstration belt in China,world-class industrial clusters such as electronic information,equipment manufacturing,household appliances,automobiles,textiles and clothing have been formed,which has greatly promoted the economic development of related cities.Meanwhile,industrial pollution accompanied by industrial agglomeration has become an urgent problem to be solved.The environmental externalities of industrial agglomeration have always been a hot topic.Some scholars have further refined the agglomeration to explore the impact of specialization and diversity on environmental pollution,but so far there is no consensus.In addition,there are few literatures in the academic circles about the factors affecting the externalities of specialization and diversity.This article is based on the related theories such as the agglomeration environmental externalities and the cluster life cycle theory.The central topic is"What is the difference between the environmental externalities of specialization and diversity and their influencing factors",which meets the actual needs of the sustainability of the YREB,also has certain theoretical and practical significance.Based on the related theories and existing research,this paper insists that the impact of specialization and diversity on industrial pollution has two sides,depending on the comparison between the positive environmental externality and the negative environmental externality.Under this framework,this paper proposes three theoretical hypotheses.Then,paper uses panel data of 108 prefecture-level cities in the YREB during 2004-2012 to conduct empirical tests.The research includes the following aspects:（1）the degree of specialization and diversity agglomeration are measured.The spatial pattern of industrial agglomeration and industrial pollution emissions in the YREB are described with Arc GIS 10.0;（2）The impacts of specialization and diversity on the intensity of industrial SO₂emissions are estimated by fixed effects model,as well as identifying the factors affecting the environmental externalities;（3）Based on the threshold model,test the evolution of specialization and diversity agglomeration have what impact on the industrial pollution emissions.The main conclusions of this research are as follows:（1）During the study period,compared with the eastern of the region,the types of industries in the upper reaches of the YREB are more unitary,while the degree of diversity was reversed.The degree of specialization in most cities has declined,while the degree of diversity in most cities has increased.The industrial pollution emission intensity of upstream cities is significantly higher than that of downstream cities.Moreover,cities with high pollution intensity are increasingly concentrated in the upper reaches of the Yangtze River Economic Belt.（2）Specialization and diversity jointly affect the intensity of industrial pollution emissions.An increase in professionalism will lead to an increase in industrial pollution.On the contrary,diversity has a significant inhibitory effect on industrial pollution emissions.In addition,there are differences in the factors that affect the externalities of specialization and diversity.FDI,technology,and environmental regulations are conducive to improving the positive externalities of specialization and agglomeration,and economic scale and technology are the main factors that increase the positive externalities of diversity.（3）This paper verifies the important impact of industrial linkages on the externalities of diverse agglomeration environments.The positive environmental externalities of relevant diversity agglomeration are significantly higher than that of non-relevant diversity agglomeration.In addition,the external influence of economic scale,science and technology and other factors on the agglomeration environment also mainly occurs through the relevant diversity of agglomeration.This shows that the positive externalities of the diverse agglomeration environment depend on industrial linkages.（4）As the life cycle of agglomeration changes,the environmental externalities of specialization and diversity will change.The relationship between specialization and industrial pollution emissions is roughly"U";the relationship between related diversity and industrial pollution emissions is roughly an inverted"U"relationship.Irrelevant diversity has always inhibited industrial pollution emissions,but will has weakened with the development of agglomeration,like “L”.