Knowra Trichlorofluoromethane Trichlorofluoromethane Trichlorofluoromethane, or CFC-11, is a colorless, nonflammable chlorofluorocarbon formerly used as a refrigerant and aerosol propellant. Its release depletes stratospheric ozone.
Ozone depletion : The reduction of ozone in the stratosphere, caused in part by chlorine released from human-made chemicals. Ultraviolet light breaks down CFC-11, freeing chlorine that catalytically destroys ozone.
Refrigerant : A working fluid that transfers heat in a refrigeration or air-conditioning system. CFC-11 was widely used as a low-pressure refrigerant in large cooling equipment.
Thomas Midgley Jr. : An American engineer and chemist associated with the development and promotion of leaded gasoline and CFC refrigerants. Midgley helped introduce CFC refrigerants as safer alternatives to earlier toxic or flammable fluids.
Ozone hole : The seasonal springtime depletion of stratospheric ozone over Antarctica. CFC-11 contributed chlorine to the chemistry responsible for severe Antarctic ozone loss.
Chlorine radical : A chlorine atom with an unpaired electron, highly reactive in atmospheric chemistry. This reactive product of CFC-11 photolysis drives its ozone-destroying catalytic cycles.
Aerosol propellant : A gas or liquefied gas that expels product from an aerosol container. CFC-11's nonflammability and chemical stability suited it to aerosol sprays.
Chlorofluorocarbon : A compound made of chlorine, fluorine, and carbon, historically used in refrigerants, propellants, and foam production. CFC-11 belongs to this stable, ozone-depleting family of industrial chemicals.
Montreal Protocol assessment : Scientific evaluations of ozone-layer recovery and the effects of controls under the Montreal Protocol. Measurements of CFC-11 abundance help assess whether the phaseout is working as intended.
Stratosphere : The atmospheric layer above the troposphere, extending from roughly 10 to 50 kilometers in altitude. CFC-11 persists long enough to reach this layer, where ultraviolet radiation releases chlorine.
Foam blowing agent : A substance used to create gas bubbles that expand a polymer into foam. CFC-11 also expanded rigid polyurethane insulation and other foams.
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