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.

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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

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Example Sentences

Its aim was to reduce the most harmful air pollutants - nitrogen dioxide and particulate matter.

From BBC • May 27, 2026

Despite more knowledge and awareness of the effects of pollution, the presence of nitrogen dioxide and other pollutants has reduced both in the long-term and in recent years.

From BBC • May 13, 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

This new analysis is the first nationwide evaluation of how much nitrogen dioxide people encounter from both indoor and outdoor sources, including gas stoves, vehicle traffic, and electricity generation.

From Science Daily • Dec. 3, 2025

When slowly heated in a vacuum vessel until ignition takes place, some nitrogen dioxide, NO2, is also produced.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 6 "Groups, Theory of" to "Gwyniad" by Various