Sulfur Dioxide (SO2)
SO2 Attainment Designation Recommendations to EPA (06/2011)
Sulfur dioxide is one of a group of highly reactive gasses known as "oxides of sulfur." Nationwide, the largest source of sulfur dioxide is fossil-fuel combustion at power plants. State regulations require that most of the coal burned in Michigan contain low amounts of sulfur. Sulfur dioxide also is emitted from smelters, petroleum refineries, pulp and paper mills, and steel mills. Other sources include residential, commercial, and industrial space heating and the burning of high sulfur fuels by locomotives, large ships, and non-road diesel equipment. Sulfur dioxide also contributes to the formation of fine particle pollution in the atmosphere.
Human exposure to sulfur dioxide aggravates existing respiratory and cardiovascular disease. Asthmatics and individuals with chronic lung and/or cardiovascular disease, children, and the elderly are most at risk. Short-term exposures are now linked to adverse respiratory effects.
Deposition of sulfur dioxide can potentially acidify lakes, streams, and soils and corrode building surfaces.
Sulfur Dioxide Standards
On June 22, 2010, the sulfur dioxide National Ambient Air Quality Standards were revised by the U.S. Environmental Protection Agency. The revised standard is set at 75 parts per billion (ppb), which is attained when the 3-year average of the 99th percentile of 1-hour daily maximum concentrations does not exceed 75 ppb. The previous standards were set in 1971, and the State continued to maintain an attainment designation for sulfur dioxides since October 20, 1982.
Michigan has made a recommendation to the Environmental Protection Agency on the appropriate designations for this new standard based on the most recent ambient monitoring. The recommendation was for a designation of "nonattainment" for an area in Wayne County, and an "unclassifiable" designation for the remainder of the state.
For more information about Sulfur Dioxide (SO2); please contact Robert Irvine at 517-373-7042.
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