English: Ozone–oxygen cycle in the ozone layer.

1. Oxygen molecules are photolyzed, yelding 2 oxygen atoms (SLOW)

2. Ozone and oxygen atoms are continuosly being interconverted as solar UV breaks ozone and the oxygen atom reacts with another oxygen molecule (FAST)

3. Ozone is lost by a reaction of the oxygen atom or the ozone molecule with each other, or some other trace gas such as chlorine (SLOW)

This interconversion process converts UV radiation into thermal energy, heating the stratosphere