Which pollutant is most responsible for depletion of the ozone layer?
Chlorofluorocarbons are stable in the lower atmosphere and can persist long enough to reach the stratosphere. Ultraviolet radiation there photolyses them, releasing chlorine radicals. A chlorine radical catalytically converts ozone to molecular oxygen and is regenerated, allowing one atom to destroy many ozone molecules. This mechanism produced severe polar ozone depletion and motivated international controls under the Montreal Protocol. At organismal level, respiratory surfaces are especially exposed because large volumes of air contact thin, moist epithelia designed for rapid gas exchange. S
Ref: Campbell Biology, Urry et al., 12th Ed., Unit 8 Ecology