Ozonabbauende

Ozonabbauende, which translates to "ozone-depleting" in English, refers to substances that have the ability to chemically destroy the ozone layer in the Earth's stratosphere. This layer is crucial for life on Earth as it absorbs most of the Sun's harmful ultraviolet (UV) radiation. When ozone-depleting substances (ODS) are released into the atmosphere, they are transported to the stratosphere. There, under the influence of UV radiation, they break down into highly reactive molecules, such as chlorine and bromine atoms. These atoms then initiate catalytic cycles that convert ozone (O3) into oxygen (O2), thereby reducing the concentration of ozone in the stratosphere.

The most well-known ODS are chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, carbon tetrachloride, and methyl chloroform. These chemicals were widely used in refrigerants, aerosols, fire suppressants, and solvents due to their chemical stability and non-toxicity in terrestrial applications. However, this very stability allowed them to persist long enough in the atmosphere to reach the stratosphere. The realization of their damaging effect led to international agreements, most notably the Montreal Protocol on Substances that Deplete the Ozone Layer, signed in 1987. This protocol mandated a phase-out of the production and consumption of most ODS, which has been largely successful in halting and beginning to reverse the depletion of the ozone layer. Despite this progress, some ODS have long atmospheric lifetimes, meaning their effects will continue for decades.