CHLOROFLUOROCARBONS (CFCs)

Chlorofluorocarbons or CFCs (also known as Freon) are non-toxic, non-flammable and non-carcinogenic. They contain fluorine atoms, carbon atoms and chlorine atoms. The 5 main CFCs include CFC-11 (trichlorofluoromethane - CFCl₃), CFC-12 (dichloro-difluoromethane - CF₂Cl₂), CFC-113 (trichloro-trifluoroethane - C₂F₃Cl₃), CFC-114 (dichloro-tetrfluoroethane - C₂F₄Cl₂), and CFC-115 (chloropentafluoroethane - C₂F₅Cl).

CFCs are widely used as coolants in refrigeration and air conditioners, as solvents in cleaners, particularly for electronic circuit boards, as a blowing agents in the production of foam (for example fire extinguishers), and as propellants in aerosols. Indeed, much of the modern lifestyle of the second half of the 20^th century had been made possible by the use of CFCs.

Man-made CFCs however, are the main cause of stratospheric ozone depletion. CFCs have a lifetime in the atmosphere of about 20 to 100 years, and consequently one free chlorine atom from a CFC molecule can do a lot of damage, destroying ozone molecules for a long time. Although emissions of CFCs around the developed world have largely ceased due to international control agreements, the damage to the stratospheric ozone layer will continue well into the 21^st century.

Before the Montreal Protocol, CFCs were used in a variety of industrial and commercial appliances.

DOING OUR BIT FOR THE OZONE LAYER

There are a number of steps that we can all take both as individuals and as groups to protect the Earth's ozone layer. We have all been part of the ozone depletion problem, through the use of chemicals in everyday products. However, we can all be part of the solution.

Following the Montreal Protocol most ozone depleting chemicals (ODCs) have or are being phased out of use in most target applications such as aerosols, refrigeration and air conditioning. However, consumer products bought prior to international agreements may still be in use in our homes and offices and cannot easily be replaced. Large appliances, such as refrigerators, have long lifetimes and early replacement would entail great cost. Proper care and maintenance of equipment to ensure that the CFCs they contain are never released to the atmosphere should be applied. Remember that a single CFC molecule can destroy 100,000 ozone molecules.

In addition, if purchasing fire extinguishers try to avoid any that contain halons, which have bromine in them. Purchase carbon dioxide, water, or dry chemical extinguishers instead. Finally, although foam packaging is CFC-free, some products contain HCFCs (hydrochlorofluorcarbons), which while far less damaging to the ozone layer, could contribute substantially to global warming. Avoid those that do. Use and re-use non-disposable packaging.