EPA is proposing to redesignate as “attainment/unclassifiable” certain “unclassifiable” areas in Missouri, Ohio, Nebraska, and Texas. When these areas were initially designated, EPA did not have sufficient information to determine if they attained the 2010 1-hour health-based National Ambient Air Quality Standard for Sulfur Dioxide.

Since then, the states added additional monitoring to better understand air quality in those areas. EPA now has sufficient information to determine that these areas are attaining the 2010 1-hour SO₂ primary NAAQS. EPA is also proposing to approve requests for redesignation from the states of Nebraska, Ohio, and Texas.  EPA has not received a formal request to redesignate the Missouri area, so the Agency is concurrently notifying the Governor of its recommendation that the area be redesignated to attainment/unclassifiable, based on currently available information.

Read the proposal here.

The letter to the Governor of Missouri, and a summary fact sheet are below.

• Letter to Governor of Missouri (PDF)(3 pp, 268 K)
• Fact Sheet: Redesignation of Certain Unclassifiable Areas for the 2010 1-Hour Sulfur Dioxide Primary National Ambient Air Quality Standard (PDF)(3 pp, 161 K)