From Ecopedia

Overview

Chlorofluorocarbons are man-made organic compounds developed in 1930s for use in various commercial, household and industrial applications.

Chlorofluorocarbons containing chlorine, fluorine and carbon, are produced as volatile derivatives of ethane and methane for commercial purposes. CFCs, most commonly known by Freon, a DuPont trade name, are generally represented by Freon-12 or R-12 (dichlorodifluoromethane).

Chemical Properties

CFCs are non-toxic, non-carcinogenic, non-reactive and non-flammable substances possessing stable thermodynamic characteristics. CFCs can be easily converted from a gas to liquid or vice versa, making the compounds most suitable for use as refrigerants, aerosol-spray propellants, blowing agents as well as electronic solvents.

Environmental Information

CFCs and Ozone Depletion

As a result of CFCs extensive usage, large amounts of chlorine that is present in the CFCs is getting released into the atmosphere. Typically, the chemical inertness of the CFCs allows longer atmospheric residence periods, enabling global distribution of the compound.

Ultraviolet (UV) radiation coming from the sun causes the release of free chlorine atoms into the stratosphere (ozone layer) of the atmosphere, causing the depletion of the ozone layer and increasing the harmful UV radiation to dangerous levels.

Since the lifetime of the CFCs in the earth’s atmosphere is around 20 to 100 years, a single chlorine atom released from a CFC molecule could cause significant damage to the ozone molecules for a very long time.

Control Measures

Presently, several international control agreements enabled considerable reductions in CFC emissions.

Montreal Protocol

Signed in 1987, the Montreal Protocol committed around 170 nations to minimize the emissions of certain halogenated hydrocarbon groups, which are found to contribute to the depletion of ozone layer.

Certain amendments to the protocol were adopted to accelerate the phasing out of CFCs among other ozone-depleting substances including halons.

References

http://en.wikipedia.org/wiki/Chlorofluorocarbon http://en.wikipedia.org/wiki/CFC http://www.ciesin.org/TG/OZ/cfcozn.html http://www.theozonehole.com/cfc.htm http://www.answers.com/topic/chlorofluorocarbon http://www.enotes.com/science-fact-finder/environment/how-do-chlorofluorocarbons-affect-earths-ozone http://www.enviropedia.org.uk/Global_Warming/CFCs.php http://www.ace.mmu.ac.uk/eae/ozone_depletion/older/CFCs.html http://www.ornl.gov/sci/engineering_science_technology/eere_research_reports/electrically_driven_heat_pumps/fluids_development/cfc_and_hcfc_replacements/ornl_tm_9817/ornl_tm_9817.pdf http://www.answers.com/topic/montreal-protocol