The Stratospheric Photochemistry of Chlorine Compounds and Its Influence on the Ozone Layer
Most gaseous chemical species released at the surface of the earth are removed from the atmosphere rather rapidly, and consequently are not important as stratospheric pollutants. Among the effective tropospheric removal processes or sinks are rainout and washout, especially for water-soluble species; biological interactions; and decomposition by absorption of visible (400–700 nm) or near ultraviolet (300–400 nm) solar radiation. Chemical reaction, either with surface materials or with common tropospheric gaseous species (for example OH radicals), can also be very effective in other cases. However, whenever a molecular species is reasonably inert toward these tropospheric interactions, the molecules can survive long enough to penetrate into the stratosphere and become potential stratospheric pollutants. As such molecules rise higher and higher into the stratosphere, they become exposed to shorter and shorter wavelengths of ultraviolet light, and eventually, at high enough altitudes, all diatomic or polyatomic molecules can be photochemically decomposed by intense solar ultraviolet radiation.
KeywordsSkin Cancer Ozone Concentration Stratospheric Ozone Chlorine Compound Atmospheric Lifetime
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- 2.“Halocarbons: Effects on Stratospheric Ozone”, U.S. National Academy of Sciences, Washington, D. C., 1976.Google Scholar
- 3.Climatic Impact Assessment Program Monographs. Six volumes. U.S. Department of Transportation, DOT-TST-75- 51, Washington, D. C., 1975. See especially Vol. 1, “The Natural Stratosphere of 1974.”Google Scholar
- 4.“Environmental Impact of Stratospheric Flight. Biological and Climatic Effects of Aircraft Emissions in the Stratosphere”. Climatic Impact Committee, National Research Council, National Academy of Sciences, National Academy of Engineering, Washington, D. C. 1975.Google Scholar
- 6.“Fluorocarbons and the Environment”, Report of Federal Task Force on Inadvertent Modification of the Stratosphere (IMOS), June, 1975.Google Scholar
- 7.“Measurements of Ultraviolet Radiation in the United States and Comparisons with Skin Cancer Data”, J.Scott, T.R. Fears and G. B. Gori, National Cancer Institute, DHEW No. (NIH) 76–1029, 1976.Google Scholar
- 9.“Free Chlorine in the Stratosphere: an In Situ Study of CI and CIO”, J. G. Anderson, J.J. Margitan and D. H. Stedman, preprint, February, 1977.Google Scholar
- 10.Upper Limit for Stratospheric ClONO2 from Balloon-Borne Infrared Measurements”, D. G. Murcray, A. Goldman, W.J. Williams, F. H. Murcray, F.S. Bonomo, C.M. Bradford, G. R. Cook, P.L. Hanstand M.J. Molina, preprint, Mar. 1977.Google Scholar
- 12.F.S. Rowland and M.J. Molina, paper presented at the American Chemical Society Meeting, Atlantic City, N.J., September 1974.Google Scholar
- 16.“Stratospheric Photodissociation of Several Saturated Perhalo Chlorofluorocarbon Compounds in Current Technological Use (Fluorocarbons-13, 113, 114, 115),” C.C. Chou, R.J. Milstein, W. S. Smith, H. Vera Ruiz, M. J. Molina and F. S. Rowland, J. Phys. Chem. (in press)Google Scholar
- 17.“Greenhouse Effect Due to Chlorofluorocarbons: Climatic Implications”, V. Ramanathan, Science, 190, 50 (1975).Google Scholar
- 19.“The Fluorocarbon-Ozone Theory II: Tropospheric Lifetimes; An Estimate of the Tropospheric Lifetime of CCl3F”, J. P. Jesson, P. Meakin, and L. C. Glasgow, preprint published in “Chlorofluorocarbon Effects and Regulations”, U.S. Senate Hearings on Dec. 15, 1976.Google Scholar