Photochemical

The air was infected with photochemical smog.

Source: tatoeba (18234)

Closer to the ground, ozone can also be created by photochemical reactions between the sun and pollution from vehicle emissions and other sources, forming harmful smog.

Source: tatoeba (6548037)

Oxygen was later produced and introduced into our atmosphere through two processes; photochemical dissociation, caused by the breakup of water molecules by the sun’s ultraviolet light, and photosynthesis, the process that uses carbon dioxide and water (H₂O) to form organic compounds while also releasing oxygen (O₂).

Source: tatoeba (11549898)

The O–O bond in benzoyl peroxide and the C–N bonds in AIBN homolyze under thermal or photochemical conditions.

Source: wiktionary