Properties
- include fluorinated, chlorinated and brominated organic compounds
- colourless and odourless gases
Main sources
- use and inappropriate disposal of products with halogenated organic compounds
- aerosol cans
- synthetic foam
- refrigeration
- technical cleaning
- fire protection
Impacts
- not toxic to humans and animals in normally occurring concentrations
- affects the climate, contributes to the greenhouse gas effect
- chlorinated and brominated compounds: major cause of ozone layer depletion in the stratosphere
Measures
- global ban on ozone-depleting substance classes of chlorofluorocarbons (CFCs), persistent brominated organic compounds (halons, methyl bromide) and the chlorinated solvent carbon tetrachloride and 1,1,1-trichloroethane (Montreal Protocol)
- fluorinated compounds included in the Kyoto Protocol adopted in 1997 to reduce greenhouse gases
- ban on chemical substitutes such as Hydrochlorofluorocarbons (HCFCs) in industrial nations and to some degree in developing nations; replaced by hydrofluorocarbons (HFCs)
Status and changes
ozone-depleting substances were released into the atmosphere in large quantities especially in the 1970s and 1980s. These emissions have decreased significantly around the world since the 1990s.
