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nitrogen dioxide

American  

noun

Chemistry.
  1. a reddish-brown, highly poisonous gas, NO 2 , used as an intermediate in the manufacture of nitric and sulfuric acids, and as a nitrating and oxidizing agent; a major air pollutant from the exhaust of internal combustion engines that are not fitted with pollution control devices.


nitrogen dioxide British  

noun

  1. a red-brown poisonous irritating gas that, at ordinary temperatures, exists in equilibrium with dinitrogen tetroxide. It is an intermediate in the manufacture of nitric acid, a nitrating agent, and also an oxidizer for rocket fuels. Formula: NO 2

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Example Sentences

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Environmental and public health advocates have consistently opposed new smog check waivers, noting they increase exhaust emissions such as nitrogen dioxide that are damaging to human health.

From Los Angeles Times ● Sep. 17, 2026

EPA officials said on a call Monday that the change will not include pollutants that directly harm health such as carbon monoxide and nitrogen dioxide, which are regulated separately.

From Los Angeles Times ● Sep. 14, 2026

London had high levels of the harmful gas nitrogen dioxide which comes from motor vehicles.

From BBC ● Aug. 18, 2026

According to one study, nitrogen dioxide -- a gas emitted by cars -- dropped by 40 percent between 2012 and 2022 in the Paris region.

From Barron's ● Mar. 15, 2026

The nitrogen dioxide formed in this reaction can now enter into combination with a new quantity of sulphur dioxide, steam, and oxygen, and the series of reactions go on indefinitely.

From An Elementary Study of Chemistry by William McPherson

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