Sulfur dioxide (chemical formula SO₂) is produced by burning sulfur or sulfur-containing compounds. It is also produced by burning coal and, e.g., producing metals from their sulfides, like copper sulfide. Natural sources of sulfur dioxide are volcanoes and algae-producing di-methyl sulfide, which is converted to sulfur dioxide in the ambient atmosphere.

Sulfur dioxide is used in paper-making and other chemical processes as a bleaching agent. It is formed as the first step in the production of sulfuric acid, which has very wide applications. Fossil fuels, such as coal and oil, can contain sulfur from trace amounts to a few percent and the combustion of these fuels results in emissions of sulfur dioxide. The only fossil fuel which can contain little or practically no sulfur is natural gas.

Sulfur emissions by fossil fuel-fired facilities can be greatly reduced (>95%) by the application of wet and dry desulfurization installations, based on either washing with a calcium hydroxide solution or reaction with calcium oxide.

References

• David R.Lide, ed (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3.
• A/F.Holleman and E.Wiberg (2001), Inorganic Chemistry, San Diego: Academic Press, ISBN 0-12-352651-5
• Norman N.Greenwood and Alan Earnshaw (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. p. 700. ISBN 0080379419.
• C.Michael Hogan. 2010. Abiotic factor. Encyclopedia of Earth. Topic ed. Emily Monosson; Ed.-in-chief Cutler J.Cleveland. Environmental Information Coalition, National Council for Science and the Environment. Washington DC