Photochemical

The air was infected with photochemical smog.

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.

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).

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

Between 1826 and 1837, Nicéphore Niépce, credited with taking the first successful photograph, in 1827, and Louis Daguerre, the most famous photographic innovator of his day, found that silver iodide was especially light sensitive, and they used this discovery as the basis for their early work, which even then had begun to gain international notice. By 1842, others found that when sunlight hit a gelatin emulsion containing silver iodide, soon to be called a daguerreotype plate, it induced a photochemical reaction. Practical photography was born.

[…] Kodak's production of photochemicals, and Sheppard worked out a method of suspending pulverized coal in fuel oil for use in U.S. Navy ships. By the spring of 1918 Sheppard had developed a collodial mixture containing chemical […]

Troubleshooting emulsion artifacts: Many problems will be averted by consulting Kodak materials and Reference 4 before the first experiment. Because nuclear track emulsions are very sensitive to chemical contaminants, especially metals and photochemicals, Kodak recommends three controls for every experiment: blank, charged slides (no tissue), charged slides with unlabeled tissues (not hybridized), and charged slides with hybridized (radioactive) tissue sections.