: 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 greenhouse gas rating is a 5 and the smog rating is a 6; both out of 10.
—
Tony Leopardo, The Mercury News, 12 Jan. 2025
Researchers also noted an increase in lung cancer cases, but the incline was commonly attributed to other types of inhaled toxins, like automobile exhaust, tar fumes and factory smog.
—Sonja Anderson, Smithsonian Magazine, 11 Jan. 2025
Those who grew up in the 1970s would remember smog reports and jokes about certain industrial cities.
—Martin Jarzebowski, Forbes, 9 Jan. 2025
One of the most unusual cases handled during his tenure was filed in April against 12 people accused of designing and running a decade-long scheme to fake out California’s smog check system for automobiles, Talbert said.
—Sharon Bernstein, Sacramento Bee, 7 Jan. 2025
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Tony Leopardo, The Mercury News, 12 Jan. 2025
Researchers also noted an increase in lung cancer cases, but the incline was commonly attributed to other types of inhaled toxins, like automobile exhaust, tar fumes and factory smog.
—Sonja Anderson, Smithsonian Magazine, 11 Jan. 2025
Those who grew up in the 1970s would remember smog reports and jokes about certain industrial cities.
—Martin Jarzebowski, Forbes, 9 Jan. 2025
One of the most unusual cases handled during his tenure was filed in April against 12 people accused of designing and running a decade-long scheme to fake out California’s smog check system for automobiles, Talbert said.
—Sharon Bernstein, Sacramento Bee, 7 Jan. 2025
See all Example Sentences for smog
Dictionary Entries Near smog
Cite this Entry
“Smog.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/smog. Accessed 20 Jan. 2025.
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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