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 Standard for Fine Particulate Matter and Approval of Associated Maintenance Plan

The Environmental Protection Agency (EPA) is issuing this Advanced Notice of Proposed Rulemaking (ANPR) to inform the public of currently available information that will be used by the Administrator to issue a subsequent action to propose redesignation of the Missouri portion of the St. Louis MO-IL nonattainment area for the 1997 PM2.5 NAAQS, (hereafter referred to as the ``St. Louis area'' or ``area''). On September 2, 2011, Missouri, through the Missouri Department of Natural Resources (MDNR) submitted a request for EPA to redesignate the Missouri portion of the St. Louis MO-IL nonattainment area to attainment for the 1997 Annual National Ambient Air Quality Standards (NAAQS) for fine particulate matter (PM2.5) and approve a state implementation plan (SIP) revision containing a maintenance plan for the Missouri portion of the area. In advance of any potential rulemaking to address the state of Missouri's request, EPA is specifically requesting early input and comments on its interpretation that currently available data support a finding that the area will be attaining the 1997 Annual PM2.5 NAAQS based on air quality monitoring data from 2015- 2017, and on EPA's advanced notice of its expectation that the state's plan for maintaining the 1997 Annual PM2.5 NAAQS for the St. Louis Area (maintenance plan) including the associated motor vehicle emission budgets (MVEBs) for nitrogen oxides (NOX) and PM2.5 for the years 2008-2025 is approvable. EPA will take any information received from this ANPR into consideration when developing a proposed action for redesignating the Missouri portion of the St. Louis Area to attainment for the 1997 Annual PM2.5 NAAQS.