Ozone update.Every fall, the hole in Earth's ozone layer ozone layer or ozonosphere, region of the stratosphere containing relatively high concentrations of ozone, located at altitudes of 12–30 mi (19–48 km) above the earth's surface. (protective gas in the upper atmosphere) opens wide. This year's hole was nearly the size of North America--35 percent larger than in 2002, when it shrank and split in two. But scientists remain convinced that the ozone hole ozone hole n. An area of the ozone layer, such as the large area over Antarctica or the smaller area over the North Pole, that periodically becomes depleted of ozone. will slowly disappear. "Ozone holes should be smaller by the time today's teens are in their mid to late 20s," says scientist Craig Long of the National Oceanic and Atmospheric Administration Noun 1. National Oceanic and Atmospheric Administration - an agency in the Department of Commerce that maps the oceans and conserves their living resources; predicts changes to the earth's environment; provides weather reports and forecasts floods and hurricanes and . That's thanks to a law in 1987 banning chlorofluorocarbons chlorofluorocarbons (klōr'əfl  r`əkär'bənz, klôr'–) (CFCs), organic compounds that contain carbon, chlorine, and fluorine atoms. (CFCs), or ozone-chewing chemicals, from aerosol cans and refrigerators. CFCs released before the ban have hovered above Earth's icy poles for decades before finally breaking down. An unusual cold spell in Antarctica this year sped up ozone depletion.--N.F.
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