Photochemical reaction

Refers to any chemical reaction which occurs as a result of light energy from the sun.

For example, ozone is formed through a photochemical reaction involving nitrogen dioxide and reactive organic compounds.

Source: DNREC online   A history of air pollution events

The adjective "photochemical" also describes substances that react or that are formed under the action of the sun.

Ozone

Nitrogen Dioxide

Climate Change

Ozone layer depletion