The Environmental Protection Agency (EPA) is taking final action to determine that the Muscatine sulfur dioxide (SO<INF>2</INF>) nonattainment area attained the 2010 1-hour SO<INF>2</INF> primary national ambient air quality standard (NAAQS) by the applicable attainment date of October 4, 2018, based upon a weight-of-evidence analysis using available air quality information. Additional analysis of the attainment determination is provided in a Technical Support Document (TSD) included in the docket to this rulemaking. This action addresses the EPA's obligation under a consent decree which established a deadline of March 31, 2022 for the EPA to determine under Clean Air Act (CAA) section 179(c) whether the Muscatine SO<INF>2</INF> nonattainment area attained the NAAQS by the October 4, 2018, attainment date. The consent decree deadline was extended to June 30, 2022.