Ozone-depleting substances

Substances listed in the Montreal Protocol on Substances that Deplete the Ozone Layer.

Ozone-depleting substances (ODS) are chemical compounds that significantly contribute to the damage of the ozone layer in the stratosphere. This layer protects the Earth from harmful ultraviolet (UV) radiation by absorbing most of this radiation. The depletion of the ozone layer has far-reaching health and ecological consequences, including an increased risk of skin cancer and various eye diseases, as well as negative effects on plant and animal biodiversity.

Among the most well-known ODS are chlorofluorocarbons (CFCs), partly halogenated fluorocarbons (HCFCs), halons, and methyl bromide. These substances are mostly halogenated organic compounds that are activated by the influence of UV radiation in the atmosphere. This process leads to the release of reactive halogen atoms, particularly chlorine and bromine radicals, which then act as catalysts and break down ozone molecules.

The harmful effect of these substances is determined by their ozone-depleting potential (ODP), which measures their efficiency compared to trichlorofluoromethane. Additionally, many ozone-depleting substances also have a high global warming potential (GWP), meaning they contribute to global warming.International agreements such as the Montreal Protocol have heavily regulated or even banned the use and production of these substances. Nevertheless, the burden of such substances remains due to their long atmospheric lifetime, which increases the need to develop alternative substances and promote sustainable solutions.