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

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

Many of these groups already face high outdoor nitrogen dioxide levels from vehicle exhaust and industrial activity.

From Science Daily • Dec. 3, 2025

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

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