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: 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
Example Sentences
the city's smog was once so bad that darkness often prevailed, even at noon
Recent Examples on the Web
Within the voluminous report, the air district outlines dozens of potential measures that could reduce smog-forming nitrogen oxides and bring the region closer to meeting the 2015 ozone standard, which it is required to meet by 2037.
—
Tony Briscoestaff Writer, Los Angeles Times, 5 Dec. 2022
It’s estimated that the transportation sector is responsible for more than half of all of California’s carbon pollution, 80 percent of smog-forming pollution and 95 percent of toxic diesel emissions.
—Rob Nikolewski, San Diego Union-Tribune, 25 Nov. 2022
Keeping our water supplies from vanishing — and our homes from burning down, our bodies from overheating and our lungs from choking with smog — will require working through conflicts like the one on Mormon Mesa.
—Sammy Rothstaff Writer, Los Angeles Times, 2 Feb. 2023
Today, smog levels and visibility in Los Angeles have improved.
—WSJ, 14 Dec. 2022
From right, Vehicles drive along a highway as smog lingers over Salt Lake City.
—Evan Bush, NBC News, 7 Dec. 2022
This week in 1952, a dense smog descended on London, England.
—Scott Lafee, San Diego Union-Tribune, 6 Dec. 2022
Volcanic emissions include sulfur dioxide, which reacts with other elements in the atmosphere and can begin to form fine particles which cause vog, a type of volcanic air pollution known as volcanic smog.
—Aya Elamroussi, CNN, 6 Dec. 2022
As another November approaches in the Indian capital, millions of residents will be left gasping for breath because of notorious seasonal smog.
—Time, 28 Oct. 2022
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Tony Briscoestaff Writer, Los Angeles Times, 5 Dec. 2022
It’s estimated that the transportation sector is responsible for more than half of all of California’s carbon pollution, 80 percent of smog-forming pollution and 95 percent of toxic diesel emissions.
—Rob Nikolewski, San Diego Union-Tribune, 25 Nov. 2022
Keeping our water supplies from vanishing — and our homes from burning down, our bodies from overheating and our lungs from choking with smog — will require working through conflicts like the one on Mormon Mesa.
—Sammy Rothstaff Writer, Los Angeles Times, 2 Feb. 2023
Today, smog levels and visibility in Los Angeles have improved.
—WSJ, 14 Dec. 2022
From right, Vehicles drive along a highway as smog lingers over Salt Lake City.
—Evan Bush, NBC News, 7 Dec. 2022
This week in 1952, a dense smog descended on London, England.
—Scott Lafee, San Diego Union-Tribune, 6 Dec. 2022
Volcanic emissions include sulfur dioxide, which reacts with other elements in the atmosphere and can begin to form fine particles which cause vog, a type of volcanic air pollution known as volcanic smog.
—Aya Elamroussi, CNN, 6 Dec. 2022
As another November approaches in the Indian capital, millions of residents will be left gasping for breath because of notorious seasonal smog.
—Time, 28 Oct. 2022
See More
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.
Word History
Etymology
smoke + fog
First Known Use
1880, in the meaning defined above
Phrases Containing smog
Dictionary Entries Near smog
Cite this Entry
“Smog.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/smog. Accessed 31 Mar. 2023.
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
nounˈsmäg 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
More from Merriam-Webster on smog
Nglish: Translation of smog for Spanish Speakers
Britannica English: Translation of smog for Arabic Speakers
Britannica.com: Encyclopedia article about smog
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