Freon fire is a trademark for any of several organic compounds containing fluorine (fluorocarbons) and sometimes chlorine (chloroflurocarbons, or CFCs). It is nonflammable, nontoxic, and noncorrosive, they have low boiling points, which makes them useful as refrigerants. By the mid-1970s they were in wide use in refrigeration and air conditioning systems, as blowing agents for plastic foams, as fire-extinguishing agents, and in aerosol sprays. Evidence has accumulated that decomposition of CFCs in the stratosphere destroys ozone.
Depletion of ozone in stratosphere causes direct as well as indirect harmful effects Ozone strongly absorbs solar UV radiation, causing atmospheric temperature to climb to about 30°F (0°C) at the top of the layer, and preventing much of this radiation from reaching earth's surface, where it would injure many living things. Chloroflurocarbons, or CFCs, and some other air pollutants that diffuse into the ozone layer destroy ozone. In the mid-1980s, scientists discovered that a "hole" — an area where the ozone is up to 50% thinner than normal — develops periodically in the ozone layer above Antarctica. This severe regional depletion, explained as a natural seasonal depletion, appears to have been exacerbated by the effects of CFCs, and may have led to an increase in skin cancer caused by UV exposure.
No comments:
Post a Comment