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Chlorofluorocarbons (CFCs) and other halogenated ozone-depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion. The total amount of effective halogens (chlorine and bromine) in the stratosphere can be calculated and are known as the equivalent effective stratospheric chlorine (EESC).
The ozone depletion potential (ODP) of a chemical compound is the relative amount of degradation to the ozone layer it can cause, with trichlorofluoromethane (R-11 or CFC-11) being fixed at an ODP of 1.0. Chlorodifluoromethane (R-22), for example, has an ODP of 0.05. CFC 11, or R-11 has the maximum potential amongst chlorocarbons because of the ...
CFC-113 is a very unreactive chlorofluorocarbon. It remains in the atmosphere about 90 years, [ 9 ] sufficiently long that it will cycle out of the troposphere and into the stratosphere . In the stratosphere, CFC-113 can be broken up by ultraviolet radiation (UV, sunlight in the 190-225 nm range), generating chlorine radicals (Cl•), which ...
NASA projection of stratospheric ozone, in Dobson units, if chlorofluorocarbons had not been banned. Animated version . By 1987, in response to a dramatic seasonal depletion of the ozone layer over Antarctica , diplomats in Montreal forged a treaty, the Montreal Protocol , which called for drastic reductions in the production of CFCs.
Trichlorofluoromethane, also called freon-11, CFC-11, or R-11, is a chlorofluorocarbon (CFC). It is a colorless, faintly ethereal, and sweetish-smelling liquid that boils around room temperature. [5] CFC-11 is a Class 1 ozone-depleting substance which damages Earth's protective stratospheric ozone layer. [6]
The hole in the ozone layer over the South Pole shrank to the smallest it's been in 30 years in 2019, and this year, scientists are eagerly watching and waiting to see what 2020 means for the ...
Fluoroalkanes are not ozone depleting, as they contain no chlorine or bromine atoms, and they are sometimes used as replacements for ozone-depleting chemicals. [19] The term fluorocarbon is used rather loosely to include any chemical containing fluorine and carbon, including chlorofluorocarbons , which are ozone depleting.
The largest Antarctic ozone hole recorded (September 2006) 2012 retrospective video by NASA on the Montreal Protocol The Montreal Protocol on Substances That Deplete the Ozone Layer [2] is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion.