photochemical smog

American  

noun

Meteorology.

1. air pollution containing ozone and other reactive chemical compounds formed by the action of sunlight on nitrogen oxides and hydrocarbons, especially those in automobile exhaust.

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Etymology

Origin of photochemical smog

First recorded in 1957; photo- + chemical

Example Sentences

It was a Caltech professor, Arie Jan Haagen-Smit, not GM engineers or chemists, who proved in the 1950s the connection between motor vehicles and the lethal photochemical smog over the cities and suburbs of California.

From Scientific American

This was Los Angeles’ first episode of “photochemical” smog.

From Scientific American

“The light wind hinders effective dispersion of air pollutants. The sunshine enhances photochemical smog activities and the formation of ozone during the daytime, resulting in high pollution in the region.”

From New York Times

Oxidized nitrogen becomes part of photochemical smog and ozone and is a major component of the infamous PM 2.5, particulate matter less than 2.5 microns in diameter that decreases visibility and is harmful when inhaled because it can penetrate deeply into the lungs.

From Scientific American

Cars in Tokyo cause an eye-stinging photochemical smog.

From Time Magazine Archive