Energy and Environment MonitorOn November 16, 2009, U.S. EPA proposed to adopt a new 1-hour primary national ambient air quality standard (NAAQS) for sulfur dioxide (SO2) at a level between 50 and 100 parts per billion (ppb), based on the 3-year average of the annual 99th percentile (or 4th highest) of 1-hour daily maximum concentrations. U.S. EPA is also proposing to revoke both the existing 24-hour primary standard of 140 ppb and annual primary SO2 standard of 30 ppb. Alternatively, U.S. EPA is seeking comment on a 1-hour NAAQS up to 150 ppb. At a level of 150 ppb, U.S. EPA would retain the existing 24-hour and revoke only the annual standard. Comments are due 60 days after U.S. EPA publishes the proposal in the Federal Register. U.S. EPA will hold a public hearing for its proposed rule on January 5, 2010 in Atlanta, Georgia, and is obligated under a consent decree to sign a final rule on the primary SO2 primary NAAQS by June 2, 2010. For the pre-publication version of the proposed rule, click here.
Any final revised SO2 NAAQS will affect facilities that burn fossil fuels, including power plants and other industrial facilities. U.S. EPA estimates, based upon 2005 emissions data, that fossil fuel combustion at power plants and other industrial facilities accounts for 66% and 29%, respectively, of total U.S. SO2 emissions. Other sources of SO2 emissions include industrial processes such as extracting metal from ore, and the burning of high sulfur fuels by locomotives, large ships, and non-road equipment.
If the SO2 NAAQS is revised as proposed, additional areas could be classified as nonattainment, meaning the area does not meet the standard. For a map of the counties designated nonattainment for the current SO2 standard, click here. Based upon data from 2006-2008, U.S. EPA projects that 45 counties have monitors that would exceed a NAAQS of 100 ppb, 22 additional counties for a total of 67 counties would violate a standard of 75 ppb, and 40 additional counties for a total of 147 counties would exceed a standard of 50 ppb. For a map of counties with monitors currently violating proposed range for 1-hour SO2 standard of 50-100 ppb, click here. For a map of counties with monitors projected to violate proposed range for 1-hour SO2 standard of 50-100 ppb in 2020, click here.
If U.S. EPA signs the final revised SO2 NAAQS in June 2010, then state governors would have an opportunity to submit to U.S. EPA recommendations for the areas in their state that should be “designated” or identified as “attainment” (i.e., meeting the standard), “nonattainment” (i.e., failing to meet the standard), or “unclassifiable” (i.e., information is not available). The state governors’ recommendations would be due in June 2011, and U.S. EPA would promulgate final designations in June 2012, within two years of the anticipated effective date of the final revised standard, if any. No later than 120 days before the agency promulgates the designations, U.S. EPA must give notice to the states of any modifications to their initial designations. This notification of any modifications would be due in February 2012 if U.S. EPA adheres to its schedule and promulgates final designations in June 2012. In the event of insufficient information, the Clean Air Act provides that U.S. EPA can take an additional year or until June 2013 to designate areas.
The final designation date is important because attainment dates or the latest date by which a nonattainment area is required to attain or meet the NAAQS is determined from the effective date of the nonattainment designation for the area. Areas designated nonattainment must achieve the NAAQS “as expeditiously as practicable, but no later than 5 years from the date such area[s were] designated nonattainment”. If U.S. EPA promulgates final SO2 designations by June 1, 2012, then nonattainment areas would be required to meet the SO2 standard no later than the summer of 2017.
This article was authored by Gale Lea Rubrecht, Jackson Kelly PLLC. For more information on the author, see here.
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