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

---

Example Sentences

See Examples For:

nitrogen dioxide

The proposed changes pertain to a 2023 rule designed to tamp down NOx -- shorthand for nitric oxide and nitrogen dioxide -- from truck tailpipes, beginning with model year 2027.

From Barron's ● Jul. 9, 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

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

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