Chlorofluorocarbons or CFCs (also known as Freon) are non-toxic, non-flammable and non-carcinogenic. They contain fluorine, carbon atoms and chlorine atoms. The 5 main CFCs are CFC-11 (trichlorofluoromethane - CFCl3), CFC-12 (dichlorodifluoromethane - CF2Cl2), CFC-113 (trichlorotrifluoroethane - C2F3Cl3), CFC-114 (dichlorotetrafluoroethane - C2F4Cl2), and CFC-115 (chloropentafluoroethane - C2F5Cl).
CFCs are widely used as liquid refrigerants in refrigerators and air conditioners, as solvents and strippers, especially for electronic circuit boards, as blowing agents in the production of foam (for example in extinguishers) and as propellants in spray cans. Many aspects of modern life styles in the second half of the twentieth century were made possible through the use of CFCs.
However, synthetic CFCs are the main cause of the destruction of the stratospheric ozone layer. CFCs have a lifetime in the atmosphere of around 20 to 100 years, and consequently each atom of free chlorine from a molecule of CFC can cause much damage, destroying ozone molecules over a long period. Although CFC emissions from the developed world have largely ceased through international monitoring agreements, the damage to the stratospheric ozone layer will continue for a long time to come ...