Figure 3. Ozone is destroyed in a 3 step catalytic process. The first ozone molecule is photolyzed to form an O atom and and the first oxygen molecule. In step 2, the catalyst reacts with another ozone molecule to form XO and the second oxygen molecule. Finally, the XO molecule reacts with the O atom to form a third oxygen molecule, and to reform the original catalyst. The catalyst converts 2 oxone molecules into 3 oxygen molecules without being affected itself. A typical chlorine atom can destroy thousands of ozone molecules in this fashion.