In the first quarter of 2016, EPA has taken several actions in relation to the 2010 Sulfur Dioxide (SO2) National Ambient Air Quality Standard (NAAQS). EPA established the primary 1-hour SO2 NAAQS at 75 parts per billion (ppb) in June of 2010. In 2013, EPA designated 29 areas in 16 states as nonattainment based on three years of air monitoring data but made no further designations. To settle litigation brought by environmental groups and certain states claiming that EPA had not timely designated all areas of the country, a consent decree was entered in 2015 scheduling three deadlines for EPA to finalize area designations: the first by July 2, 2016, the second by December 31, 2017 and the third by December 31, 2020. 

A SO2 NAAQS nonattainment designation invokes the general nonattainment area planning requirements of the Clean Air Act and its SO2 specific planning requirements, including the emissions inventory, attainment demonstration, reasonably available control measures (RACM) and reasonably available control technology (RACT), reasonable further progress (RFP) and contingency measures that must be submitted to EPA as part of the nonattainment State Implementation Plan (SIP). A nonattainment SIP is required to demonstrate that an area will attain the NAAQS as expeditiously as practicable but no later than five years from the effective date of designation. For the areas designated as nonattainment for the SO2 NAAQS in 2013, the nonattainment area SIPs were due on April 4, 2015 and would have been required to demonstrate attainment by October 4, 2018. On March 18, 2016, EPA published a final rule finding that 11 states, including Kentucky, Ohio and West Virginia, had failed to submit SO2 nonattainment area SIP submittals for areas designated as nonattainment in 2013. However, EPA noted that both Kentucky and Ohio had submitted redesignation requests for the Campbell-Clermont nonattainment area in each state. EPA has not acted on these requests, but if it approves redesignation, neither state would be required to submit a nonattainment SIP for the area. See 81 Fed. Reg. 14736 (March 18, 2016). Jefferson County, Kentucky is also named in the EPA finding; however, Kentucky has stated that the most recent 2015 data shows Jefferson County to be attaining the standard and is working to demonstrate attainment based on the three-year average of monitoring data. 

As previously reported in the Dinsmore Air Quality Letter, the areas EPA is required to designate by July 2, 2016 consist of two groups: (1) areas that have newly monitored violations of the 2010 SO2 NAAQS; and (2) areas that contain any stationary sources that had not been announced as of March 2, 2015 for retirement and that according to EPA’s Air Markets Database emitted in 2012 either more than 16,000 tons of SO2 or more than 2,600 tons of SO2 with an annual average emission rate of at least 0.45 pounds of SO2/mmBTU. Consistent with the Clean Air Act designation process, states were provided the opportunity to make recommendations to EPA regarding designations of areas. On or about February 16, 2016, EPA notified states of its intended designations and, in many instances, did not accept the state recommendations. For instance, Kentucky’s Ohio and Pulaski counties were recommended by the state for attainment designations, but EPA intends to designate both as “unclassifiable” meaning EPA determined it did not have sufficient information to designate the areas. States were given until April 19, 2016 to submit additional information to EPA prior to final designation. Additionally, EPA provided a 30-day public comment period that ended on March 31, 2016 to solicit input from interested parties other than states. 

Also in March, EPA responded to the first step under the Data Requirements Rule (DRR), which requires states to identify and characterize, through monitoring or modeling, all sources that have SO2 emissions in excess of 2,000 tons per year (tpy) for the most recent year for which emissions data is available. Federally enforceable emission limits, adopted and effective by January 13, 2017, may also be established to ensure a source will emit less than 2,000 tpy of SO2. In this first step, states submitted their lists of sources by January 15, 2016, and EPA posted its responses to each list on April 13, 2016 at The only states with no sources to be addressed under the DRR are Alaska, Delaware, Idaho, Massachusetts, New Jersey, Rhode Island and Vermont. By July 1, 2016, air agencies must identify for each listed source whether monitoring or modeling will be used to characterize air quality in the respective area or whether the source will accept federally established limits on emissions.