Hydrofluorocarbons (HFC's)

"Hydrofluorocarbons (HFCs) are compounds containing carbon, hydrogen, and fluorine. Certain chemicals within this class of compounds are viewed by industry and the scientific community as acceptable alternatives to chlorofluorocarbons and hydrochlorofluorocarbons on a long-term basis. Because the HFCs contain no chlorine they do not directly affect stratospheric ozone. Furthermore, mechanisms for ozone destruction involving fragments produced as HFCs are decomposed within the atmosphere (CF3 radicals) have been shown to be insignificant.

Like HCFCs, the HFCs contain hydrogen that is susceptible to attack by the hydroxyl radical. Oxidation of HFCs by the hydroxyl radical is believed to be the major destruction pathway for HFCs in the atmosphere. Atmospheric lifetimes of the most commonly used HFCs (HFC-134a and HFC-152a) are limited to <12 yrs because of this reaction.

Although it is believed HFCs will not deplete ozone within the stratosphere, this class of compounds has other adverse environmental effects (see the Chlorofluorocarbon Alternatives Measurement Project info)-for example, these gases are efficient absorbers of infrared radiation. Concern over these effects may make it necessary to regulate production and use of these compounds at some point in the future. Such restrictions have been proposed in the Kyoto Protocol." - The US Global Monitoring Lab