Results of the mediation test.

Environmental regulation has played an essential function in reducing pollution and it also influences the flow of labor. Although studies on employment and environmental regulation have gained prominence, most researches ignore the heterogeneity of regulatory tools and its discrepant impacts on different skilled labor; moreover, few literatures have explored how environmental regulations affect employment. Therefore, this study creatively incorporates environmental regulation, industrial green transformation and employment skill structure into a unified analytical framework, categorizing environmental regulations into command-and-control type, market-incentive type and voluntary type and analyzing the heterogeneous influences of environmental regulations on employment skill structure. Meanwhile, we explore the indirect impact of environmental regulations on the employment skill structure from the mediating role of industrial green transformation. The following are the research findings: (1) From a national perspective, both command-and-control and market-incentive types present a U-shaped association with employment skill structure, and their intensity has not surpassed the turning point yet; while the voluntary type is positively connected with the employment skill structure. (2) From the regional analysis, the findings in central and western areas are consistent with the national results; while the market-incentive and voluntary types show a reciprocal U-shaped connection with employment skill structure in eastern, and their regulatory intensity is in the rising stage of the curve. (3) Industrial green transformation acts as a partly mediator between market-incentive type and employment skill structure, but presents a suppression effect between command-and-control type, voluntary type, and employment skill structure. This paper takes industrial green transformation as the mediating variable, which emphasizes the importance of industrial green transformation and enhances the understanding on the mechanism of environmental regulation influencing employment skill structure. The research results provide theoretical support and significant reference for China in formulating policies to facilitate industrial green transformation, mitigate pollution, and optimize employment skill structure.环境规制在污染治理中发挥着核心作用，同时也对劳动力流动产生影响。尽管有关就业与环境规制的研究已备受关注，但多数研究均忽视了规制工具的异质性，以及其对不同技能劳动力的差异化影响；此外，鲜有文献深入探讨环境规制对就业的具体作用路径。据此，本研究创新性地将环境规制、工业绿色转型（industrial green transformation）与就业技能结构（employment skill structure）纳入统一分析框架，将环境规制划分为命令控制型（command-and-control）、市场激励型（market-incentive）与自愿型（voluntary）三类，分析环境规制对就业技能结构的异质性影响。同时，本研究以工业绿色转型为中介变量，探究环境规制对就业技能结构的间接影响效应。本研究的核心结论如下：（1）全国层面视角下，命令控制型与市场激励型环境规制均与就业技能结构呈U型关联，且当前二者的规制强度尚未越过拐点；而自愿型环境规制则与就业技能结构呈显著正相关关系。（2）区域异质性分析显示，中西部地区的研究结论与全国层面结果一致；而东部地区的市场激励型与自愿型环境规制则与就业技能结构呈倒U型关联，且当前二者的规制强度处于曲线上升阶段。（3）工业绿色转型在市场激励型环境规制与就业技能结构之间发挥部分中介作用，而在命令控制型、自愿型环境规制与就业技能结构之间则呈现遮掩效应。本研究以工业绿色转型作为中介变量，凸显了工业绿色转型的重要性，深化了对环境规制影响就业技能结构作用机制的认知。本研究结论可为中国制定相关政策提供理论支撑与重要参考，以推动工业绿色转型、加强污染治理并优化就业技能结构。