Knowra Ozone-depleting substance Ozone-depleting substance An ozone-depleting substance is a chemical whose atmospheric reactions reduce stratospheric ozone, often by releasing chlorine or bromine that catalytically destroys ozone molecules.
Ozone layer : A region of the stratosphere with relatively high ozone concentrations that absorbs much of the Sun’s ultraviolet radiation. These substances matter because their reactions thin this protective stratospheric region.
Chlorofluorocarbon : A compound containing carbon, chlorine, and fluorine, historically used in refrigeration, aerosols, and foam production. This widely used substance class became a major source of stratospheric chlorine.
Mario Molina : A Mexican chemist who helped establish how chlorofluorocarbons can destroy stratospheric ozone. His research with F. Sherwood Rowland identified the atmospheric threat from chlorofluorocarbons.
Ozone depletion : The reduction of ozone concentration in the stratosphere through chemical and physical processes. This is the atmospheric change caused by emissions of ozone-depleting substances.
Catalytic ozone destruction : A reaction cycle in which a catalyst converts ozone into oxygen without being consumed. Chlorine and bromine released from many substances destroy ozone through catalytic cycles.
Halons : Bromine-containing compounds developed primarily for use in fire extinguishers. Their bromine content gives these fire suppressants unusually high ozone-depletion potential.
F. Sherwood Rowland : An American chemist whose research with Mario Molina showed how chlorofluorocarbons can deplete ozone. Their 1974 analysis connected widely used chemicals to stratospheric ozone destruction.
Ultraviolet radiation : Electromagnetic radiation with wavelengths shorter than visible light and longer than X-rays. Thinner ozone allows more harmful ultraviolet radiation to reach Earth’s surface.
Chlorine radical : A chlorine atom with an unpaired electron, capable of reacting rapidly with atmospheric molecules. Ultraviolet light can release chlorine radicals from chlorinated substances in the stratosphere.
Hydrochlorofluorocarbon : A compound containing hydrogen, chlorine, fluorine, and carbon, used as a transitional substitute for chlorofluorocarbons. They deplete ozone less than many chlorofluorocarbons but were also scheduled for phaseout.
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