Assessing the effectiveness of PM pollution control from the perspective of interprovincial transport and PM mitigation costs across China.

Due to the transboundary nature of air pollutants, a province's efforts to improve air quality can reduce PM concentration in the surrounding area. The inter-provincial PM pollution transport could bring great challenges to related environmental management work, such as financial fund allocation and subsidy policy formulation. Herein, we examined the transport characteristics of PM pollution across provinces in 2013 and 2020 via chemical transport modeling and then monetized inter-provincial contributions of PM improvement based on pollutant emission control costs. We found that approximately 60% of the PM pollution was from local sources, while the remaining 40% originated from outside provinces. Furthermore, about 1011 billion RMB of provincial air pollutant abatement costs contributed to the PM concentration decline in other provinces during 2013-2020, accounting for 41.2% of the total abatement costs. Provinces with lower unit improvement costs for PM, such as Jiangsu, Hebei, and Shandong, were major contributors, while Guangdong, Guangxi, and Fujian, bearing higher unit costs, were among the main beneficiaries. Our study identifies provinces that contribute to air quality improvement in other provinces, have high economic efficiency, and provide a quantitative framework for determining inter-provincial compensations. This study also reveals the uneven distribution of pollution abatement costs (PM improvement/abatement costs) due to transboundary PM transport, calling for adopting inter-provincial economic compensation policies. Such mechanisms ensure equitable cost-sharing and effective regional air quality management.