The EPA is taking final action to amend its regulations relating to the Clean Air Act (CAA) requirement that Federal actions conform to the appropriate State, Tribal or Federal implementation plan for attaining clean air ("general conformity") to add de minimis emissions levels for particulate matter with an aerodynamic diameter equal or less than 2.5 microns (PM<INF>2.5</INF>) National Ambient Air Quality Standards (NAAQS) and its precursors.