smog

noun \ ˈsmäg , ˈsmȯg \

|Updated on: 14 Jul 2018

Definition of smog

: 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

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smogless

play \ˈsmä-gləs, ˈsmȯ-\ adjective

See smog defined for English-language learners

See smog defined for kids

Examples of smog in a Sentence

the city's smog was once so bad that darkness often prevailed, even at noon

Recent Examples of smog from the Web

In addition to Fresno, take Salt Lake City, where pollution is a fact of life: The city sits in a basin, and wintertime inversions trap a thick coat of visible smog over the city for days at a time.

— jason plautz, WIRED, "Cheap, Portable Sensors Are Democratizing Air-Quality Data," 11 July 2018
But their capital has become the land of choking smog, as ger dwellers burn coal to ward off the cold.

— simon denyer, Washington Post, "Mongolia’s nomadic way of life threatened by climate change, neglect, modernity," 8 July 2018
For days, volcanic smog hung over the skies off the coast — a reminder that on the other side of the Big Island, Kilauea was erupting violently and magnificently.

— vanessa hua, SFChronicle.com, "Stargazing summer," 5 July 2018
At an embassy town hall last month in Beijing, U.S. officials fielded questions from a standing room-only crowd, on issues such as how to distinguish symptoms of an acoustic attack from those caused by exposure to Beijing’s heavy smog.

— te-ping chen, WSJ, "U.S. Evacuates More Americans From China After Mystery Illness Complaints," 1 July 2018
Another decision swept aside a key pillar of Maryland's plan to reduce soot and smog.

— christina tkacik, baltimoresun.com, "Who is Brett Kavanaugh? The Marylander might be Trump's next Supreme Court pick," 28 June 2018
The government has made strides in curbing smog and slowing the growth of emissions of carbon dioxide and other planet-warming gases.

— chris buckley, New York Times, "In a High-Stakes Environmental Whodunit, Many Clues Point to China," 24 June 2018
In the nadir of the 1970s, choked by smog regulations and forced to contend with unleaded gasoline, manufacturers built massive V8s that wheezed.

— blake z. rong, Popular Mechanics, "The Evolution of the Combustion Engine," 5 June 2018
Like laze, this portmanteau sews together two words—volcano and smog—to describe the acidic haze that commonly forms due to volcanic emissions.

— maya wei-haas, Smithsonian, "A Brief Glossary of Volcano Vocab," 25 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'smog.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of smog

smoke + fog

NEW! Time Traveler

First Known Use: 1881

in the meaning defined above

See Words from the same year

smog Synonyms

Synonyms

fog, haze, mist, murk, reek, soup;

Other Climate/Meteorology Terms

monsoon, occlusion, ozone, rime, squall, zephyr

SMOG Defined for English Language Learners

smog

noun

Definition of smog for English Language Learners

: fog mixed with smoke : a cloud of dirty air from cars, factories, etc., that is usually found in cities

SMOG Defined for Kids

smog

noun \ ˈsmäg \

Definition of smog for Students

: a fog made heavier and thicker by the action of sunlight on polluted air

History for smog

The word smog was coined in England in 1905 by combining the words smoke and fog. The person who coined the word wanted to more accurately describe the atmosphere in London caused by fog mixing with smoke from coal furnaces used for heating. In the United States smog often describes any sort of visible air pollution, such as the haze around cities produced by automobile exhaust affected by sunlight.