Researched
Chlorofluorocarbons (CFCs)
Midgley's Freon (1930) gives safe refrigerators and spray cans, but later damages the ozone layer.
Open in the interactive tree →CFCs replaced toxic refrigerants such as ammonia and sulphur dioxide. Their long life lets them reach the stratosphere; after the ozone hole was found in 1985 they were phased out under the Montreal Protocol (1987), a lesson in unintended consequences.
Prerequisites
Unlocks
- Ozone hole and Montreal Protocol1987CFCs are the gases behind the ozone hole and the Montreal Protocol
- Green Chemistry1998