smog

noun

ˈsmäg 

ˈsmȯg

: a fog made heavier and darker by smoke and chemical fumes

also : a photochemical haze caused by the action of solar ultraviolet radiation on atmosphere polluted with hydrocarbons and oxides of nitrogen especially from automobile exhaust

smogless

ˈsmä-gləs 

ˈsmȯ-

adjective

Synonyms of smog

• haze
• fog
• cloud
• mist

Examples of smog in a Sentence

the city's smog was once so bad that darkness often prevailed, even at noon

Recent Examples on the Web

The report analyzes ozone, smog and particle pollution. —Stephanie Stahl, CBS News, 23 Apr. 2026

South Florida air quality was graded by American Lung Association, which analyzed 2022-2024 data to grade counties on unhealthy levels of smog and soot. —Samantha Neely, USA Today, 23 Apr. 2026

In this case, nitrogen oxides and what are called volatile organic chemicals react with sunlight to create ground-level ozone, the principal component of smog. —Andrea Thompson, Scientific American, 22 Apr. 2026

Ozone pollution, also called smog, is the presence of ground-level ozone that forms when chemicals like nitrogen oxides and volatile organics from electric utilities, car exhaust, gasoline vapors, industrial facilities and chemical solvents react to sunlight. —Jen Christensen, CNN Money, 22 Apr. 2026

Word History

Etymology

smoke + fog

First Known Use

1880, in the meaning defined above

Phrases Containing smog

• anti-smog

Rhymes for smog

• blog
• bog
• clog
• cog
• dog
• flog
• fog
• frog
• grog
• hog
• jog
• log

Kids Definition

smog

noun

ˈsmäg 

also ˈsmȯg

: a thick haze caused by the action of sunlight on air polluted especially by smoke and automobile exhaust fumes

Etymology

from smoke and fog

Medical Definition

smog

noun

ˈsmäg also ˈsmȯg

: a fog made heavier and darker by smoke and chemical fumes

also : a photochemical haze caused by the action of solar ultraviolet radiation on atmosphere polluted with hydrocarbons and oxides of nitrogen especially from automobile exhaust