Changes
In the stratosphere it serves a very important function, by acting to filter out most of the sun's ultraviolet radiation.
Some activists claimed that this ozone scientists have measured a thinning layer has been threatened in recent decades by the release of ozone over the north and south poles resulting from [[chlorofluorocarbons]], on the theory that these 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>
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[[category:Chemistry]]
