Word: cfcs
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Dates: during 1986-1986
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...oxygen molecules that protects the earth's surface from the sun's harmful ultraviolet radiation, a form of light just beyond the human range of vision. Speculation on the reason for these "holes" has ranged from weather patterns and solar activity to the action of man-made chlorofluorocarbons (CFCs), chemicals used as spray-can propellants, refrigerants and industrial solvents...
...content of the hole had dropped by about 40%. Says Team Leader Susan Solomon, a chemist with the National Oceanic and Atmospheric Administration in Boulder, Colo.: "We suspect a chemical process is fundamentally responsible," although atmospheric dynamics undoubtedly help shape it. The chemicals could be natural -- volcanic, perhaps -- but CFCs might play a role...
...split some of them apart. The single oxygen atoms tend to attach themselves to the remaining molecules, forming an oxygen-atom triplet. The result: a layer, from six to 30 miles up, of ozone-enriched air. Once formed, an ozone molecule is a good absorber of ultraviolet. But when CFCs rise to the ozone layer, sunlight decomposes them, releasing the chlorine they contain. The chlorine is a catalyst, breaking ozone apart without itself being affected. At present, the ozone layer lets enough ultraviolet through to cause sunburn and, in some people, skin cancer. More ultraviolet would increase the effect...