Nationwide, the largest source of sulfur dioxide comes from coal-burning 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, transportation sources, and steel mills. Other sources include residential, commercial, and industrial space heating. 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 susceptible. Sulfuric acid is a component of acid rain, which can potentially acidify lakes, streams, and soils and corrode building surfaces.

Statewide levels of sulfur dioxide have remained near one-fourth of the annual standard (0.030 ppm) since 1991. Monitored levels statewide also have remained well below the 24-hour standard (0.14 ppm not to be exceeded more than once per year). The state has continued to maintain an attainment designation for sulfur dioxide since October 20, 1982.

Other Resources:

• Sulfur Dioxide Attainment Map
• Sulfur Dioxide Monitoring
• Sulfur Dioxide Real-Time Data

Recommended EPA Resources:

• SO₂ - How Sulfur Dioxide Affects the Way We Live & Breathe