The Montreal Protocol is an international treaty that aims to protect the ozone layer by phasing out the production and consumption of ozone-depleting substances (ODS). ODS are chemicals that contain chlorine or bromine, which can destroy the ozone molecules in the stratosphere. CFCs, or chlorofluorocarbons, are a group of ODS that were widely used in refrigeration, air conditioning, aerosols, and solvents. The Montreal Protocol banned the production of CFCs in 201012. Freon is a trade name for some CFCs and HCFCs, or hydrochlorofluorocarbons, which are also ODS but less harmful than CFCs. The Montreal Protocol also controls the production of HCFCs, which are being phased out gradually12. Ammonia is not an ODS and is not regulated by the Montreal Protocol1.
The Montreal Protocol on Substances That Deplete the Ozone Layer | U.S. Department of State2 Montreal Protocol - Wikipedia1 The Montreal Protocol: fixing the ozone layer and taking climate action - Canada.ca3