smog

American  

[smog, smawg] / smɒg, smɔg /

noun

1. smoke or other atmospheric pollutants combined with fog in an unhealthy or irritating mixture.

2. photochemical smog.

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verb (used with object)

1. to cover or envelop with or as if with smog.

smog British  

/ smɒɡ /

noun

1. a mixture of smoke, fog, and chemical fumes

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smog Scientific  

/ smŏg /

1. A form of air pollution produced by the reaction of sunlight with hydrocarbons, nitrogen compounds, and other gases primarily released in automobile exhaust. Smog is common in large urban areas, especially during hot, sunny weather, where it appears as a brownish haze that can irritate the eyes and lungs. Ozone, a toxic gas that is not normally produced at lower atmospheric levels, is one of the primary pollutants created in this kind of smog.

2. Also called photochemical smog

3. Fog that has become polluted with smoke and particulates, especially from burning coal.

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smog Cultural  

1. A haze or fog composed of water vapor, complex molecules, and suspended particles.

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Discover More

In North America, the primary cause of smog is pollution from automobile exhaust.

The Los Angeles basin, where pollutants can be trapped by inversions and the surrounding mountains, has frequent problems with smog, as do other major urban areas.

The word smog is a combination of smoke and fog.

Other Word Forms

• desmog
  verb (used with object)
• smoggy
  adjective
• smogless
  adjective

Etymology

Origin of smog

1900–05; sm(oke) + ( f)og ¹

Explanation

What do you get when you combine "smoke" and "fog"? Smog! Smog is the thick haze or smoke that's caused by polluting substances in the air. Generally, the more cars there are in a city, the more likely there is to be smog. There are other culprits for smog, though, including coal-burning factories, other chemical emissions from plants and mills, and nearby forest fires. If there's too much smog in a city, it can make it hard for people with asthma to breathe.Smog is a great example of a portmanteau, a word formed by combining two other words into one: it comes from smoke and fog.

Example Sentences

Smog went on throttling Southern California — through the 1940s, into the 1950s, getting worse, not better.

From Los Angeles Times • Mar. 26, 2026

We caught films at the Vista and drank at the Smog Cutter, and John took me to sweaty punk shows at Spaceland.

From Los Angeles Times • Dec. 29, 2023

This brought an end to the Great Smog event but prompted authorities to issue the Clean Air Act of 1956, regulating both industrial and domestic smoke, to prevent a situation this dangerous occurring again.

From BBC • Dec. 5, 2023

Smog has also been reported in Manila north of Taal in recent days, but the Philippine Institute of Volcanology and Seismology said it was largely caused by vehicle emissions and not the volcano.

From Seattle Times • Sep. 22, 2023

Smog made the air seem thick, like light, yellowed fog.

From "Homecoming" by Cynthia Voigt

Related Words

• acid rain
• carbon dioxide
• fog
• smoke
• soot