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

• brume
• fog
• gauze
• haze
• mist
• murk
• reek
• soup

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 sulfur dioxide can create a volcanic smog that is hazardous to breathe. —Kenna Hughes-Castleberry, Space.com, 4 June 2025

Increasing the supply of renewable energy also helps reduce ozone pollution — a problem that plagues the Front Range during the summer when nitrogen oxides and volatile organic compounds bake in the sun and create a brown smog. —Noelle Phillips, Denver Post, 2 June 2025

Sulfur dioxide reacts in the atmosphere to create visible haze of volcanic smog, called vog. —Eduardo Cuevas, USA Today, 27 May 2025

Los Angeles, for example, has an average of over 150 days a year of unhealthy levels of ozone smog. —Anna Skinner, MSNBC Newsweek, 1 May 2025

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