Drivers of water pollutant discharge in urban agglomerations and their scale effects

Revealing the drivers and scale effects of water pollutant discharges is an important issue in study environmental consequences during urban agglomeration evolution. It also a prerequisite for realizing collaborative reduction governance agglomerations. This paper takes 305 counties Yangtze River Delta (YRD) as example selects chemical oxygen demand (COD) ammonia nitrogen (NH3—N) two distinctive indicators, using Spatial Lag Model (SLM) Error (SEM) to estimate 2011 2016. Then Multiscale Geographically Weighted Regression (MGWR) model constructed diagnose effect spatial heterogeneity drivers. The findings show that size population, level urbanization, economic development global-level increase impacts on discharges, while industrialization, social fixed assets investment, foreign direct local fiscal decentralization are local-level impacts. presents following characteristics: Social investment has strong promoting both COD NH3—N Hangzhou—Jiaxing—Huzhou region coastal area YRD; industrialization Taihu Lake basin Zhejiang province; inhibitory discharge, pollution halo more prominent marginal areas YRD such northern Jiangsu, Anhui, southern Zhejiang; noticeable discharge central YRD, reflecting positive improved awareness stronger constraints multilevel regulations agglomeration. Therefore, it recommended guide greener reduce discharge; embed push-back mechanism fields industrial production, capital financial income expenditure; establish high-quality pattern agglomerations systematically compatible with carrying capacity environment.