Ozone is not emitted directly into the air, but instead it is the product of various chemical reactions.
Ozone occurs naturally in the upper atmosphere.
The heat from the sun causes a chemical reaction in NO x and VOCs. This reaction forms ozone. Nature tries to keep a constant amount of this good ozone in the region. Measures to reduce the use of freon and CFCs are meant to protect the good ozone. Bad Ozone Bad ozone occurs at ground level.