polar ozone depletion (commonly called the ozone hole) gets

larger, additional ultraviolet rays are allowed to pass through.

These rays cause cancer, cataracts, and lowered immunity to

diseases.1 What causes the depletion of the ozone layer?

In 1970, Crutzen first showed that nitrogen oxides produced

by decaying nitrous oxide from soil-borne microbes react

catalytically with ozone hastening its depletion. His findings

started research on "global biogeochemical cycles" as well as the

effects of supersonic transport aircraft that release nitrogen

oxide into the stratosphere.2

In 1974, Molina and Rowland found that human-made

chlorofluorocarbons used for making foam, cleaning fluids,

refrigerants, and repellents transform into ozone-depleting

Chlorofluorocarbons stay in the atmosphere for several

decades due to their long tropospheric lifetimes. These compounds

are carried into the stratosphere where they undergo hundreds of

catalytic cycles with ozone.4 They are broken down into chlorine

troposphere. The remainder breaks down under exposure to

wins Nobel. Science News, 148, pp. 262

Hole Fails to Recover. Science, 266, pp.217

of the ozone is lost. This helps explain why there is less ozone

Some topics in this essay:
Bay Antarctica, HCFC-123 HFC-134a, El Chichon, Paper July, Molina Rowland, Chlorofluorocarbons CFCs, O2 ClO, ClO ClONO2, Depletion Processes, June Version, ozone depletion, 1996 june, version 17, methyl bromide, 1996 june version, june version 17, june version, ciesin 1996 june, ozone hole, ciesin 1996, depletion processes, 17 ozone, version 17 ozone, 17 ozone depletion, national oceanic,