This rule establishes air quality designations for certain areas in the United States for the 2010 primary Sulfur Dioxide (SO<INF>2</INF>) National Ambient Air Quality Standard (NAAQS). The EPA is issuing this rule to identify areas that, based on recorded air quality monitoring data showing violations of the NAAQS, do not meet the 2010 SO<INF>2</INF> NAAQS and areas that contribute to SO<INF>2</INF> air pollution in a nearby area that does not meet the SO<INF>2</INF> NAAQS. At this time, the EPA is designating as nonattainment most areas in locations where existing monitoring data from 2009-2011 indicate violations of the 1-hour SO<INF>2</INF> standard. The EPA intends to address in separate future actions the designations for all other areas for which the agency is not yet prepared to issue designations and that are consequently not addressed in this final rule. The Clean Air Act (CAA) directs areas designated nonattainment by this rule to undertake certain planning and pollution control activities to attain the NAAQS as expeditiously as practicable.