nitrogen dioxide

noun

: a toxic reddish brown gas NO₂ that is a strong oxidizing agent, is produced by combustion (as of fossil fuels), and is an atmospheric pollutant (as in smog)

Examples of nitrogen dioxide in a Sentence

Recent Examples on the Web

Now imagine that on Tuesday, the nitrogen dioxide held at 105, while ozone levels dropped to 30. — Daniel Engber, The Atlantic, 24 July 2026

At the same time, indoor levels of nitrogen dioxide decreased by 70%. — Ashwini Sehgal, The Conversation, 23 July 2026

Our sensors measure two airborne pollutants—fine particulate matter and nitrogen dioxide, like the exhaust from cars and trucks. — Tara Molina, CBS News, 13 July 2026

Even breathing in a low level of nitrogen dioxide can trigger an attack in people with asthma. — Sanja Jelic, Verywell Health, 29 Apr. 2026

Word History

First Known Use

1869, in the meaning defined above

Rhymes for nitrogen dioxide

• acetaldehyde
• acetanilide
• arabinoside
• cycloheximide
• cyclophosphamide
• diethylamide
• dinucleotide
• ferricyanide
• ferrocyanide
• glutaraldehyde
• glyceraldehyde
• hydroperoxide

Kids Definition

nitrogen dioxide

noun

: a reddish brown poisonous gas that is an air pollutant formed from automobile exhausts

Medical Definition

nitrogen dioxide

noun

: a poisonous strongly oxidizing reddish brown gas NO₂