Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Nitrogen dioxide is a reddish-brown gas with a characteristic sharp, biting odor and is one of several nitrogen oxides. This toxic gas is an important air pollutant and is the primary source of nitrate pollution in the atmosphere.
Related terms
Nitric Oxide: A colorless, poisonous gas that reacts rapidly with oxygen to form nitrogen dioxide.
Smog: A type of air pollution that results from the reaction of sunlight with nitrogen dioxide and other compounds in the atmosphere.
Acid Rain: Rainfall made sufficiently acidic by atmospheric pollution that it causes environmental harm, typically to forests and lakes. The main cause is the industrial burning of coal and other fossil fuels, which release sulfur dioxide and nitrogen dioxide into the atmosphere.