Approval and Promulgation of Air Quality Implementation Plans; 2008 Ozone NAAQS Interstate Transport for Colorado, Montana, North Dakota and South Dakota

The Environmental Protection Agency (EPA) is approving State Implementation Plan (SIP) submissions from the states of Colorado, Montana, North Dakota and South Dakota that are intended to demonstrate that the SIP for each respective state meets certain interstate transport requirements of the Clean Air Act (Act or CAA) for the 2008 8-hour ozone National Ambient Air Quality Standards (NAAQS). These submissions address the requirement that each SIP contain adequate provisions prohibiting air emissions that will have certain adverse air quality effects in other states. The EPA is approving these SIPs for all four states as containing adequate provisions to ensure that air emissions in the states do not significantly contribute to nonattainment or interfere with maintenance of the 2008 8-hour ozone NAAQS in any other state.