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

But as we would find out, our smog — photochemical smog — made the air taste like poison and look like something you’d put out with the garbage.

From Los Angeles Times • Mar. 26, 2026

Cleaner cars have wrought wonders in getting rid of photochemical smog, when all we need to do is buy one.

From Los Angeles Times • Mar. 26, 2026

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 • May 9, 2019

This ozone is a toxic component of photochemical smog.

From Textbooks • Feb. 14, 2019

In the presence of sunlight, the hydrocarbons and nitrogen oxides emitted largely by automobile exhausts react to produce the sort of brownish and irritating photochemical smog that blankets Los Angeles for most of the year.

From Time Magazine Archive