The Environmental Protection Agency (EPA) is approving a State Implementation Plan (SIP) revision submitted by the State of New Hampshire. On July 29, 2021, the State submitted its 1997 ozone national ambient air quality standards (NAAQS) Limited Maintenance Plan (LMP) for the Boston-Manchester-Portsmouth (Portsmouth) area. EPA is approving the Portsmouth area LMP because it provides for the maintenance of the 1997 ozone NAAQS through the end of the second 10- year portion of the maintenance period.

The Environmental Protection Agency (EPA) is approving a State Implementation Plan (SIP) revision submitted by the State of Iowa as meeting the Clean Air Act (CAA) requirement that each State's SIP contain adequate provisions to prohibit emissions that will significantly contribute to nonattainment or interfere with maintenance of the 2015 8-hour ozone national ambient air quality standards (NAAQS) in any other state. This action is being taken in accordance with the CAA.

The Environmental Protection Agency (EPA) is taking final action to approve a revision to the Bullhead City portion of the Arizona State Implementation Plan (SIP). These revisions concern the second 10-year maintenance plan for the Bullhead City area for the 1987 national ambient air quality standards (NAAQS or ``standards'') for particulate matter less than 10 micrometers in diameter (PM<INF>10</INF>).

The Environmental Protection Agency (EPA) is approving state implementation plan (SIP) revisions submitted by the District of Columbia (DC), State of Maryland (MD), and Commonwealth of Virginia (VA) (collectively, the States). The revisions consist of the base year inventory for the Washington, DC-MD-VA nonattainment area (the DC Area) for the 2015 ozone national ambient air quality standards (NAAQS). This action is being taken under the Clean Air Act (CAA).