Final answer:
CFCs released into the stratosphere are broken down by UV radiation which releases chlorine atoms, destroying ozone molecules in a catalytic cycle.
Step-by-step explanation:
In order for chlorofluorocarbons (CFCs) to break down ozone, they must reach the stratosphere and be exposed to ultraviolet (UV) radiation. Upon contact with UV radiation, CFCs release highly reactive chlorine atoms which act as a catalyst in the destruction of ozone molecules (O₃).
The reaction can be understood through a series of steps where a Cl atom reacts with an ozone molecule to form chlorine monoxide (ClO) and oxygen (O₂). This ClO can react with another Cl atom resulting in the release of the original chlorine atom, which is free to destroy more ozone molecules in a continuous cycle.
CFCs were found in various products like refrigerants, air conditioning systems, foams, and aerosols, contributing significantly to ozone depletion. Thanks to global initiatives and the development of alternatives such as hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs), the use of CFCs has significantly diminished.
Global efforts have reduced CFC usage by replacing them with more benign substances like HFCs and HCFCs.