What has CAUSED the depletion of the ozone layer?

:] thank you.What has CAUSED the depletion of the ozone layer?
Chlorofluorocarbon (CFC): a compound consisting of chlorine, fluorine, and carbon


CFCs are very stable in the troposphere. They move to the stratosphere and are broken down by strong ultraviolet (UV) light, where they release chlorine atoms that then deplete the ozone layer. CFCs are commonly used as refrigerants, solvents, and foam blowing agents. ozone depletion potential (ODP) for each CFC is, respectively, 1, 1, 0.8, 1, and 0.6.





Carbon tetrachloride was widely used as a raw material in many industrial uses, including the production of chlorofluorocarbons (CFCs), and as a solvent. Solvent use ended when it was discovered to be carcinogenic. It is also used as a catalyst to deliver chlorine ions to certain processes. Its ozone depletion potential is 1.2.





Consumer aerosol products in the US have not used ozone-depleting substances (ODS) since the late 1970s because of voluntary switching followed by federal regulation. The Clean Air Act and EPA regulations further restricted the use of ODS for non-consumer products. All consumer products, and most other aerosol products, now use propellants that do not deplete the ozone layer, such as hydrocarbons and compressed gases.





Class I Substance: one of several groups of chemicals with an ozone-depletion potential of 0.2 or higher


Class I substances listed in the Clean Air Act (CAA) include CFCs, halons, carbon tetrachloride, and methyl chloroform. EPA later added HBFCs and methyl bromide to the list by regulation.What has CAUSED the depletion of the ozone layer?
Kay T is correct about the CFCs.


There are also non-anthropogenic causes, e.g. supernovae and gamma-ray bursts:


http://www.spaceref.com/news/viewsr.html鈥?/a>

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