Freons (e.g., Freon-12: $$\text{CF}_2\text{Cl}_2$$) Impact

Chlorofluorocarbons (CFCs) are stable, non-flammable, and non-toxic in the lower atmosphere. When they migrate into the stratosphere, ultraviolet light decomposes them into chlorine radicals ($$\text{Cl}^\bullet$$).

Mechanism of Ozone Depletion:

$$\text{CF}_2\text{Cl}_2 \xrightarrow{h\nu} {}^\bullet\text{CF}_2\text{Cl} + \text{Cl}^\bullet$$

$$\text{Cl}^\bullet + \text{O}_3 \to \text{ClO}^\bullet + \text{O}_2$$

$$\text{ClO}^\bullet + \text{O} \to \text{Cl}^\bullet + \text{O}_2$$

A single chlorine radical continuously initiates chain reactions that destroy thousands of ozone molecules.