【摘要】 行政边界是生态环境治理“最后一公里”的关键隘口。受事权所限，以传统环保法庭为代表的环境司法制度仅能应对县域边界污染问题，难以纾解市域边界污染困境。鉴于此，本研究借助江苏环境资源审判“9+1”机制改革的准自然实验，基于2015—2023年江苏省95组跨城市毗邻“区县—区县”组对样本和PM_2.5卫星遥感数据，使用双重差分法考察环境司法事权由“跨区县”扩张至“跨城市”对市域边界污染的影响。结果表明：相较于传统环保法庭管辖模式，环境司法事权扩张产生了明显的边界污染治理效应。其主要机制为，环境司法事权扩张后的跨城市集中管辖模式能够有效强化市域边界环境司法、环保执法和促进横向府际环保合作。此外，环境司法事权扩张不能完全规避诉讼“主客场”现象，如果环保法庭与双边区县分属不同城市，上述减污效应会更强。本研究不仅对环境司法、边界污染以及法与经济学交叉领域的现有研究形成了有益补充，而且为探索边界污染治理长效机制和优化现有环境法治体系提供了经验参考。更多还原

【Abstract】 Administrative boundaries constitute the critical juncture for ecological and environmental governance at the "last mile". Constrained by jurisdictional authority, traditional environmental courts, as representative environmental judicial institutions, can only address pollution disputes at the county borders within the same municipality but struggle to resolve pollution issues along municipal boundaries. To address this gap, leveraging the quasi-natural experiment created by the reform of the "9+1" mechanism for environmental resource trials in Jiangsu Province, this study employs a difference-in-differences approach based on 95 cross-prefectural adjacent "district/county–district/county" pairs and PM_2.5 satellite remote sensing data from 2015 to 2023 to examine the environmental impacts of expanding judicial jurisdiction from inter-county to inter-city cases. The results indicate that, compared with the traditional jurisdictional model, the expansion of environmental judicial jurisdiction produced a significant effect on controlling border pollution, reducing average air pollution at municipal boundaries by approximately 1.1%. The mechanism lies in the post-reform cross-city centralized jurisdiction model, which effectively strengthens municipal boundary environmental adjudication, enhances environmental administrative enforcement, and promotes horizontal intergovernmental cooperation in environmental protection. Moreover, the pollution reduction effect is even stronger when the environmental court and the two counties involved belong to different municipalities, suggesting that the reform cannot entirely eliminate "home–away" dynamics in litigation. This study not only enriches existing research on environmental adjudication, border pollution, and the interdisciplinary field of law and economics, but also offers valuable empirical evidence for designing long-term mechanisms for managing boundary pollution and for optimizing the current environmental governance framework.更多还原