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

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

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

A 2024 investigation by the same research team found that gas stoves release nitrogen dioxide at unsafe levels that persist for hours after cooking ends.

From Science Daily • Dec. 3, 2025

A maroon-coloured powder, of composition CuNO2, is formed when pure dry nitrogen dioxide is passed over finely-divided copper at 25�-30�.

From Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 3 "Convention" to "Copyright" by Various