Notice of Data Availability Regarding Potential Changes to Required Ozone Monitoring Seasons for Colorado, Kansas, and Utah

The EPA is providing notice that it is supplementing the record to the Proposed Rule--Ambient Ozone Monitoring Regulations: Revisions to Network Design Requirements, published July 16, 2009. The EPA has placed in the docket for the Proposed Rule--Ambient Ozone Monitoring Regulations: Revisions to Network Design Requirements (Docket ID No. EPA-HQ-OAR-2008-0338) additional ambient ozone monitoring data for the period January 1, 2007, through April 30, 2010, for the states of Colorado, Kansas, and Utah that cover time periods outside of the current required ozone monitoring seasons. The data for these states consist of daily maximum 8-hour ozone concentrations. These data have become available since original analyses were completed for the proposal, which relied on ambient data covering the period 2004-2006. EPA is specifically considering how these more recent data could impact changes to the current and proposed required ozone monitoring seasons for Colorado, Kansas, and Utah.