美国环境保护署一位官员负责监督特朗普政府在回滚气候和空气污染法规方面一些最重要的举措，该机构周二表示，这位官员已于上周辞职。
The Environmental Protection Agency official who has overseen some of the Trump administration's most consequential efforts to roll back climate and air pollution regulations resigned effective last week, the agency said on Tuesday.