nitrogen dioxide

noun

: a toxic reddish brown gas NO2 that is a strong oxidizing agent, is produced by combustion (as of fossil fuels), and is an atmospheric pollutant (as in smog)

Examples of nitrogen dioxide in a Sentence

Recent Examples on the Web
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It is based on ground-level ozone, particle pollution, carbon monoxide, sulfur dioxide, and nitrogen dioxide. Steve Karnowski, Chicago Tribune, 4 June 2025 It is based on ground-level ozone, particle pollution, carbon monoxide, sulfur dioxide and nitrogen dioxide. Patrick Whittle, Los Angeles Times, 4 June 2025 The law focused on lowering levels of several pollutants known to harm human health: particulate matter (also known as particle pollution), ozone, sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead. Alejandra Borunda, NPR, 23 Apr. 2025 There's also been a 70 percent reduction in key pollutants like carbon monoxide, ozone, particulate matter, nitrogen dioxide, and sulfur dioxide. Nick Mordowanec, MSNBC Newsweek, 22 May 2025 See All Example Sentences for nitrogen dioxide

Word History

First Known Use

1869, in the meaning defined above

Time Traveler
The first known use of nitrogen dioxide was in 1869

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Cite this Entry

“Nitrogen dioxide.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/nitrogen%20dioxide. Accessed 15 Jun. 2025.

Kids Definition

nitrogen dioxide

noun
: a reddish brown poisonous gas that is an air pollutant formed from automobile exhausts

Medical Definition

nitrogen dioxide

noun
: a poisonous strongly oxidizing reddish brown gas NO2

More from Merriam-Webster on nitrogen dioxide

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