Abstract: The spatial divergence of pollution control and emission effects between central and peripheral cities has led to the occurrence of emission reduction“islands”, which restricts the high-quality development of regional green development. Based on the center-periphery spatial structure, a theoretical model of pollution control and emission spatial effects is constructed to explain the reasons for the formation of emission reduction“islands”from the perspective of heterogeneity in scale returns of production activities between cities. Combined with the panel data from 279 prefecture level cities in China from 2003 to 2016, this paper makes use of spatial network analysis and spatial econometric models to provide empirical tests for the theoretical deduction results. The findings show that under the effect of increasing returns to scale, the output level of unit pollutant emissions increases with the increase of urban centrality, and the emission control effect of the central cities is more obvious, leading to the formation of emission reduction“islands”. The spatial urban emission control effect is positively correlated, the higher the centrality of the city, the more significant its positive spatial spillover effect from other cities; and the“island”of emission reduction is further strengthened. The heterogeneity of the dominant industries between central and peripheral cities and the resulting industrial associations are the fundamental reasons for the spatial divergence of emission control effects. Therefore, it is necessary to accept the basic reality that it is difficult to automatically bridge the emission reduction gap between central and peripheral cities solely based on the internal strength of the economic system. However, policy supply can be optimized from the perspectives of promoting the transformation of green industries in the peripheral cities, accelerating the spillover of green technologies from the central cities, and enhancing the economic cooperation between central and peripheral cities, in order to maximize the relative convergence of the pollutant discharge intensity.

Key words: pollution control, core-periphery, spatial effects, emission reduction “island”