Air Plan Approval and Air Quality Designation; MO; Redesignation of the Missouri Portion of the St. Louis Missouri-Illinois Area to Attainment of the 1997 Annual Standards for Fine Particulate Matter and Approval of Associated Maintenance Plan

On January 5, 2018, the Environmental Protection Agency (EPA) published in the Federal Register an advanced notice of proposed rulemaking (ANPR) specifically requesting early input and comments on the Agency's interpretation that air quality monitoring data from 2015- 2017 support a finding that the Missouri Portion of the St. Louis nonattainment area attains the 1997 Annual National Ambient Air Quality Standards (NAAQS) for fine particulate matter (PM2.5). The notice also provided an evaluation of Missouri's 1997 Annual PM2.5 NAAQS maintenance plan, which includes the 2008 and 2025 NOX and PM2.5 motor vehicle emission budgets (MVEBs) and established the 2008 base year emissions inventory. EPA received no comments on the ANPR. EPA is now taking direct final action on three items, consistent with the ANPR. First, EPA is approving the state's request to redesignate the Missouri portion of the St. Louis MO-IL nonattainment area to attainment for the 1997 Annual PM2.5 NAAQS as the monitoring values demonstrate the area attains the standard. Second, EPA is approving the state implementation plan (SIP) revision containing a maintenance plan for the Missouri portion of the area including the motor vehicle emissions budget. Third, EPA is approving Missouri's 2008 base year emissions inventory in accordance with section 172(c)(3) of the CAA.