: 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
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 pollutant causes smog and is linked to asthma, lung disease and premature death.
—
Adam Liptak, New York Times, 2 July 2024
This is how climate change may alter 10 of the world's natural wonders
The grasses, brought in from grazing livestock decades ago, are artificially fertilized by the smog coming from the Los Angeles region, Cummings said.
—Julia Jacobo, ABC News, 14 June 2024
Collectively, the chemicals subject to these regulations also contribute to smog, so these reductions will have an additional health impact by reducing its levels as well.
—John Timmer, Ars Technica, 9 Apr. 2024
Washington — The Supreme Court on Thursday agreed to block an environmental rule that aims to curb air pollution and address harmful smog that travels from certain states into others while legal proceedings continue.
—Melissa Quinn, CBS News, 27 June 2024
See all Example Sentences for smog 
Adam Liptak, New York Times, 2 July 2024
This is how climate change may alter 10 of the world's natural wonders
The grasses, brought in from grazing livestock decades ago, are artificially fertilized by the smog coming from the Los Angeles region, Cummings said.
—Julia Jacobo, ABC News, 14 June 2024
Collectively, the chemicals subject to these regulations also contribute to smog, so these reductions will have an additional health impact by reducing its levels as well.
—John Timmer, Ars Technica, 9 Apr. 2024
Washington — The Supreme Court on Thursday agreed to block an environmental rule that aims to curb air pollution and address harmful smog that travels from certain states into others while legal proceedings continue.
—Melissa Quinn, CBS News, 27 June 2024
See all Example Sentences for smog
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'smog.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Dictionary Entries Near smog
Cite this Entry
“Smog.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/smog. Accessed 15 Jul. 2024.
Copy CitationKids 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
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