I assume you mean "the ozone [layer]".
UV-C and more energetic radiation from the Sun shatter oxygen and nitrogen molecules, at about the elevation of the ozone layer. Some of the oxygen atoms and molecules reform as ozone (with nitrogen's help).
Contaminants serve both to block some ozone production, and serve to provide a decay path for ozone. Contaminants include water vapor, and chlorine from CFC molecules that diffused to altitude.
Ozone decays with time and temperature. The Sun destroys ozone when ozone stops UV-B (and some of it later reforms...). And contaminants also decay ozone.
UV-C and more energetic radiation from the Sun shatter oxygen and nitrogen molecules, at about the elevation of the ozone layer. Some of the oxygen atoms and molecules reform as ozone (with nitrogen's help).
Contaminants serve both to block some ozone production, and serve to provide a decay path for ozone. Contaminants include water vapor, and chlorine from CFC molecules that diffused to altitude.
Ozone decays with time and temperature. The Sun destroys ozone when ozone stops UV-B (and some of it later reforms...). And contaminants also decay ozone.