They have been used in refrigerators, air conditioners, and freezers, as propellants in aerosol sprays, as foaming agents in the production of styrofoam, and as solvents. CFC's interfere with the Chapman Cycle. They inhibit the production of ozone, thus reducing the concentration of ozone in the upper atmosphere. The Ozone Hole Ozone concentrations in the upper atmosphere have been decreasing over the last twenty years. Decreasing ozone concentrations allow more damaging UV energy to reach the earth's surface.
Ozone depletion is most obvious over Antarctica.
This is due in part to the fact that the South Pole is the coldest area on earth. Once scientists discovered that the depletion of ozone in the upper atmosphere was caused by CFC's, the U.S. banned these compounds for use in propellants in aerosol sprays, and in the manufacture of styrofoam. For more information, check out The Epa or the Ozone Depletion Resource Center .