Approval and Promulgation of State Implementation Plans; State of Colorado; Interstate Transport of Pollution for the 2006 24-Hour PM2.5

The Environmental Protection Agency (EPA) is approving a May 11, 2012 State Implementation Plan (SIP) submission from the State of Colorado that is intended to demonstrate that its SIP meets certain interstate transport requirements of the Clean Air Act (Act or CAA) for the 2006 fine particulate matter (PM 2.5 ) National Ambient Air Quality Standards (NAAQS). This submission addresses the requirement that Colorado's SIP contain adequate provisions prohibiting air emissions that will have certain adverse air quality effects in other states. EPA is determining that Colorado's existing SIP contains adequate provisions to ensure that air emissions in Colorado do not significantly contribute to nonattainment or interfere with maintenance of the 2006 24-hour PM 2.5  NAAQS in any other state, or interfere with another state's measures to prevent significant deterioration of air quality or to protect visibility. EPA is also approving the portion of Colorado's submission that addresses the CAA requirement that SIPs contain adequate provisions related to interstate and international pollution abatement.