These are the substances responsible for the physical destruction of ozone. As they come in contact with an ozone molecule, they cause the third oxygen atom to detach and form an O2 molecule with another stray oxygen atom. Since they don�t react with the oxygen, the chlorine compounds remain intact and can destroy up to 150,000 ozone molecules each.
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There are a number of different CFC�s. The compounds most responsible for ozone layer destruction are CFC-11 (trichlorofluoromethane), CFCl3; CFC-12 (dichlorodifluoromethane), CF2Cl2; and CFC-113 (1,1,2 trichlorotrifluoroethane), CF2ClCFCl2. All of these compounds are excellent refrigerants, and CFC-12 is marketed by DuPont as Freon�.
The word "CFC" has become a generic term referring to any substance that is deleterious to the ozone layer. However, many destructive compounds are not CFC�s by definition. All ozone-destroying compounds contain at least one of two common elements: chlorine, or the more catalytic bromine. Compared atom-to-atom, bromine can destroy 10-100 times the number of ozone molecules as chlorine. Fortunately, its atmospheric concentration is much smaller.
One of the other O3-destructive groups is called the hydrochlorofluorocarbons, or HCFC�s. HCFC�s are organic compounds in which not all of the hydrogen atoms have been replaced by chlorine or fluorine. One such compound is R-22 (HCFC-22), CHClF2.
Some other non-CFC compounds that destroy the ozone layer include carbon tetrachloride (tetrachloromethane), CCl4; methyl chloroform (1,1,1 trichloroethane), CH3CCl3; and methyl chloride (chloromethane), CH3Cl.
The result of ozone layer depletion is a increase in ultraviolet rays at the surface. Humans, animals, marine life, and plants are all susceptible to UV radiation damage.