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  • Print publication year: 2004
  • Online publication date: June 2012

Chapter 8 - Stratospheric-ozone depletion


“If all the ozone in the atmosphere were compressed to a pressure corresponding to that at the earth's surface, the layer would be only 3 mm [0.118 in] thick… The thin stratospheric-ozone layer has proved to be an Achilles' heel that may be seriously injured by apparently moderate changes in the composition of the atmosphere.”

Swedish Academy of Sciences, announcing the award of the 1995 Nobel Prize for Chemistry to Mario Molina, F. Sherwood Rowland, and Paul Crutzen

You have read in this text many times of the major pollution problems resulting from combustion, especially fossil-fuel combustion. In this chapter we see a global issue – destruction of stratospheric ozone – which does not result from combustion. The chemicals responsible are synthetic chemicals, chlorofluorocarbons (CFCs) and halons. Stratospheric ozone is essential to life on Earth. It absorbs more than 95% of the sun's ultraviolet (UV) radiation, which could otherwise destroy most life. Stratospheric-ozone depletion led to the 1987 Montreal Protocol, the first worldwide agreement to protect the environment. Except for smuggled chemicals, the ban of ozone-depleting chemicals is working. The stratospheric-ozone layer is expected to recover, albeit slowly. Section I below examines the stratosphere and provides background on CFC uses and how ozone depletion was detected. In Section II, we see why the greatest ozone depletion occurs over Antarctica, and describe the increases in UV radiation reaching the Earth.

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Further reading
Hileman, B.Nations fight Chlorofluorocarbon (an ozone-depleting chemical) smuggling. Chemical and Engineering News, 80(12), 25 March, 2002, 30–32
Hobbs, P. V. Stratospheric chemistry, in Introduction to Atmospheric Chemistry. Cambridge: Cambridge University Press, 2000
Kerr, R. A.Ozone depletion: a brighter outlook for good ozone. Science, 297(5587), 6 September, 2002, 1623–25
Parson, E. A. and Greene, O.The complex chemistry of the international ozone agreements. Environment, 37(2), March, 1995, 16–20 and 35–43
Rowland, F. S. and Molina, M. J.Ozone depletion: 20 years after the alarm. Chemical and Engineering News, 72(33), 15 August, 1994, 8–13
Strange, C. J.Thwarting skin cancer with sun sense. Food and Drug Administration Consumer, 29(6), July/August, 1995, 10–14
Internet resources
US Department of Energy (ORNL). Current Greenhouse Gas Concentrations. (accessed January, 2004)
US Environmental Protection Agency (a US agency). 2002. (accessed August, 2002)
US Environmental Protection Agency (a US agency) 2002. The Science of Ozone Depletion. (accessed September, 2002)
US National Aeronautics and Space Administration. 2002. (accessed January, 2004)