Approval and Promulgation of Air Quality Implementation Plans; State of Colorado; Second Ten-Year PM10 Maintenance Plan for Pagosa Springs

The Environmental Protection Agency (EPA) is taking final action partially approving and partially disapproving State Implementation Plan (SIP) revisions submitted by the State of Colorado. On March 31, 2010, the Governor of Colorado's designee submitted to EPA a revised maintenance plan for the Pagosa Springs area for the National Ambient Air Quality Standards (NAAQS) for particulate matter with an aerodynamic diameter less than or equal to 10 microns (PM<INF>10</INF>). The State adopted the revised maintenance plan on November 19, 2009. As required by Clean Air Act (CAA) section 175A(b), this revised maintenance plan addresses maintenance of the PM<INF>10</INF> standard for a second 10-year period beyond the area's original redesignation to attainment for the PM<INF>10</INF> NAAQS. EPA is taking final action approving the revised maintenance plan with the exception of one aspect of the plan's contingency measures. EPA's approval includes the revised maintenance plan's 2021 transportation conformity motor vehicle emissions budget (MVEB) for PM<INF>10</INF>. In taking final action to approve the revised maintenance plan, we are taking final action to exclude from use in determining whether or not Pagosa Springs continues to attain the 24-hour PM<INF>10</INF> NAAQS, exceedances of the 24-hour PM<INF>10</INF> NAAQS that were recorded at the Pagosa Springs PM<INF>10</INF> monitor on March 22, 2009, April 3, 2009, April 5, 2010, April 28, 2010, April 29, 2010, May 11, 2010, and May 22, 2010 because the exceedances meet the criteria for exceptional events caused by high wind natural events. This action is being taken under sections 110 and 175A of the CAA.