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EPA announcement vs. scientific skepticism
Some scientists have measured a thinning layer of ozone over the north and south poles resulting from [[chlorofluorocarbons]], as they act as [[catalyst]]s to break down the O<sub>3</sub> molecules.<ref>http://ozonewatch.gsfc.nasa.gov/facts/hole.html</ref>
Some scientists have measured a thinning layer of ozone over the north and south poles resulting from [[chlorofluorocarbons]], as they act as [[catalyst]]s to break down the O<sub>3</sub> molecules.<ref>http://ozonewatch.gsfc.nasa.gov/facts/hole.html</ref>
*In April 1991, the Environmental Protection Agency announced that ozone levels in the Northern Hemisphere shrank as much as 5 percent over the United States in the past 10 years.
*A minority opinion holds that ozone depletion has little to do with CFCs and that the ozone hole may be more natural than man-made. S. Fred Singer, an environmental scientist at the University of Virginia, has argued that a rise in methane or changes in the sun's cycle may affect ozone. He also believes the lack of historical data about ozone depletion makes it difficult to determine if similar changes occurred centuries before hairspray cans were invented. [http://www.coaleducation.org/issues/DEPLET.HTM]
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[[category:Chemistry]]
[[category:Chemistry]]