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SO2 Air Quality Data Update
2005-2006 Design Values

The following is a brief summary of EPA's 2006 air quality update for sulfur dioxide (SO2) based on ambient monitoring data for the period of 2005 through 2006.

During this period:

  • All of the original 54 areas designated non-attainment for the annual SO2 NAAQS in 1990 met the SO2 NAAQS in 2006.
  • However, 1 additional area failed to meet the SO2 24-hour NAAQS in 2006 (site 420958000, Northampton County, PA, DV= 0.147 ppm)
  • Additionally, there are two violating monitors in Hawaii that are directly affected by a nearby volcano. These monitors are maintained by the National Park Service.

EPA has two primary National Ambient Air Quality Standards for sulfur dioxide: (1) annual arithmetic mean concentration of 0.03 parts per million (ppm), and (2) a 24-hour average concentration of 0.14 ppm (not to be exceeded more than once per year).

Air quality data from EPA’s Air Quality System (AQS) were used to calculate SO2 design values. The data used for these calculations were obtained from AQS on July 11, 2007. To date, no regulatory decisions on attainment status have been made for any area based on these specific calculations.

For information concerning these data, contact:
Louise Camalier
U.S. Environmental Protection Agency
Air Quality Trends and Analysis Group (C304-04)
Research Triangle Park, NC 27711
(919) 541-0200, (919) 541-3613 (FAX)


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