Ozone depletion
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Ozone depletion consists of two related events observed since the late 1970s: a lowered total amount of ozone in Earth's upper atmosphere, and a much larger springtime decrease in stratospheric ozone
Lowest value of ozone measured by TOMS each year in the ozone hole
Ozone hole in North America during 1984 (abnormally warm, reducing ozone depletion) and 1997 (abnormally cold, resulting in increased seasonal depletion). Source: NASA
Ozone levels stabilized in the 1990s following the Montreal Protocol, and have started to recover. They are projected to reach pre-1980 levels before 2075.
Air pollution 3
Chlorofluorocarbon
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Chlorofluorocarbons and hydrochlorofluorocarbons are fully or partly halogenated hydrocarbons that contain carbon, hydrogen, chlorine, and fluorine. They are produced as volatile derivatives of methan
Ozone depletion
…depletion and the ozone hole are manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants, and foam-blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons), referred to as ozone-depleting substances (ODS). These compounds are transported into the stratosphere by turbulent mixing after…
CFCs negatively affecting stratospheric ozone production
NASA projection of stratospheric ozone, in Dobson units, if chlorofluorocarbons had not been banned. Animated version.
Freon tanks awaiting CFC reclamation and container recycling in 2012