Monitoring and Management > 4. The Atmosphere >
Present information from secondary sources to write the equations to show the reactions involving CFCs and ozone to demonstrate the removal of ozone from the atmosphere
- Ultraviolet radiation causes CFCs to undergo photodissociation, producing highly reactive chlorine free radicals, such as in the case of dichlorodifluoromethane:
- Chlorine free radicals react with ozone, removing it from the atmosphere and producing highly reactive ClO free radicals:
- Due to the continual formation and decomposition of ozone in the stratosphere, oxygen free radicals are present, and these can react with ClO free radicals to reform chlorine free radicals:
- Alternatively, ClO free radicals can undergo photodissociation to reform chlorine free radicals:
- The reformation of chlorine free radicals begins the process again, resulting in a chain reaction.
- One chlorine atom can destroy thousands of ozone molecules in this process, before a reaction with methane, nitrogen dioxide or itself takes place:
