Knowra Hydrochlorofluorocarbon Hydrochlorofluorocarbon A hydrochlorofluorocarbon (HCFC) is a compound containing hydrogen, chlorine, fluorine, and carbon. HCFCs were adopted as transitional substitutes for chlorofluorocarbons because they generally deplete stratospheric ozone less, though they still damage it.
Ozone depletion : The loss of stratospheric ozone caused when reactive chemicals catalytically destroy ozone molecules. HCFCs release chlorine in the stratosphere, contributing to this process.
Chlorofluorocarbon : A compound containing chlorine, fluorine, and carbon, once widely used as a refrigerant, propellant, and solvent. HCFCs were developed as less ozone-depleting replacements for these compounds.
HCFC-22 : A hydrochlorofluorocarbon, also called chlorodifluoromethane, used mainly as a refrigerant and chemical feedstock. It became one of the most widely used HCFC refrigerants.
Kigali Amendment : A 2016 amendment to the Montreal Protocol that schedules reductions in hydrofluorocarbon production and consumption. It extended ozone-treaty action to climate-warming substitutes used after HCFCs.
Photolysis : The breaking of chemical bonds by absorption of light. Ultraviolet light breaks down HCFC molecules and can release ozone-destroying chlorine.
Montreal Protocol : A 1987 international treaty that controls substances responsible for stratospheric ozone depletion. The treaty’s controls drove the shift from CFCs to HCFCs and later alternatives.
HCFC-141b : A hydrochlorofluorocarbon, also called 1,1-dichloro-1-fluoroethane, formerly used as a foam-blowing agent and solvent. Its uses show how HCFCs replaced CFCs beyond refrigeration.
Ozone layer : The region of the stratosphere with elevated ozone concentrations that absorbs much of the Sun’s ultraviolet radiation. HCFC regulation aims to protect this atmospheric shield.
Chlorine radical : A chlorine atom with an unpaired electron that reacts readily with other substances. Chlorine radicals released from HCFCs catalyze ozone destruction.
Vienna Convention for the Protection of the Ozone Layer : A 1985 international agreement establishing cooperation to protect the ozone layer. It created the diplomatic framework that preceded controls on HCFCs.
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