Sulfur dioxide

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Colorless gas with a pungent odor. Sulfur dioxide is a common Pollutant produced from burning high sulfur Coal in metallurgical and electrical generating plants. When sulfur dioxide combines with water to form Sulfurous acid, it is especially deleterious to carbonates such as Marble and Limestone. Sulfur dioxide also tarnishes Metal and can be harmful to dyes, Paper, and Leather. Industrially sulfur dioxide is used for disinfecting and fumigating fruits and vegetables as well as for bleaching Straw and Textile fibers. Sulfur dioxide is produced by the oxidation of Pyrite at moderate humidity levels (Waller 1990).

  • See Pollutant record for a comparison table of aerosols and collection risks.

Synonyms and Related Terms

sulfurous anhydride; sulfurous oxide; sulphur dioxide; sulfur oxides; sulphur dioxide (Br.)

Personal Risks

  • Noncombustible.
  • Toxic by inhalation.
  • Strongly irritation to eyes and mucous membranes.
  • Airgas: SDS

Collection Risks

  • Metal corrosion
  • Dye fading and pigment darkening
  • Cellulose embrittlement
  • Photograph deterioration
  • Leather “red-rot”
  • Reaction with calcareous materials

Physical and Chemical Properties

Soluble in water (forming sulfuric acid), ethanol, ether.

Composition SO2
CAS 7446-09-5
Melting Point -76.1 C
Molecular Weight mol. wt. = 64.1
Boiling Point -10 C

Resources and Citations

  • R. Waller, "Pyrite Oxidation at 25C and 10-90 Percent Relative Humidity" Program and Abstracts, Society for the Preservation of Natural History Collections, Chicago, 1990.
  • M.Dimitroff, J.Lacksonen "The Diffusion of Sulfur Dioxide in Air through Stacked Layers of Paper" JAIC, 25:31-37, 1986
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 784
  • Hermann Kuhn, Conservation and Restoration of Works of Art and Antiquities, Butterworths, London, 1986
  • Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 9144
  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
  • Marjorie Shelley, The Care and Handling of Art Objects, The Metropolitan Museum, New York, 1987
  • Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
  • Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
  • The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998