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

At the station in Brintons Road, near St Mary's Stadium, the council and Environment Agency monitor levels of nitrogen dioxide, sulphur dioxide and other pollutants.

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

To understand how people are exposed to nitrogen dioxide, the team combined indoor air measurements with outdoor pollution data, information on 133 million residential buildings, and statistics on household behavior.

From Science Daily • Dec. 3, 2025

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 McPherson, William