Air Quality Designations for the 2010 Sulfur Dioxide (SO2

This rule establishes the initial air quality designations for four areas in Texas for the 2010 primary sulfur dioxide (SO 2 ) National Ambient Air Quality Standard (NAAQS). The Environmental Protection Agency (EPA) is designating three of the areas as nonattainment because they do not meet the NAAQS. One area is being designated unclassifiable because it cannot be classified on the basis of available information as meeting or not meeting the NAAQS. The designations are based on the weight of evidence for each area, including available air quality monitoring data and air quality modeling. For the areas designated nonattainment by this rule, the Clean Air Act (CAA) directs the state of Texas to undertake certain planning and pollution control activities to attain the SO 2  NAAQS as expeditiously as practicable. This action is a supplement to the final rule addressing the second round of area designations for the 2010 SO 2  NAAQS, which the EPA Administrator signed on June 30, 2016.