Ozone depletion

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Ozone depletion in the stratosphere (the ozone layer) consists of two related phenomena observed since the late 1970s: a lowered total amount of ozone in Earth's upper stratosphere, and a much larger springtime decrease in around Earth's polar regions. The latter phenomenon over the south pole is referred to as the ozone hole. There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric events. The main causes of ozone 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 being emitted from the surface, mixing much faster than the molecules can settle. Once in the stratosphere, they release atoms from the halogen group through photodissociation, which catalyze the breakdown of...

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