Which greenhouse gas is also called laughing gas?

Nitrous oxide is the greenhouse gas commonly called laughing gas.

Its chemical formula is N2O, meaning each molecule contains two nitrogen atoms and one oxygen atom. It is a colorless, nonflammable gas with a slightly sweet odor and has been used medically as an analgesic and anesthetic, especially in dentistry and childbirth. Its familiar nickname comes from the euphoria and laughter sometimes associated with inhalation.

English chemist and inventor Humphry Davy studied the gas in the late 1790s and popularized the name “laughing gas.” Recreational “laughing gas parties” became fashionable in Britain beginning in 1799, while medical use developed later. Dentist Horace Wells demonstrated nitrous oxide for pain control during a tooth extraction in 1844.

Nitrous oxide is not the same as nitrogen dioxide or nitric oxide, despite the similar names. It is also distinct from methane, ozone, and sulfur hexafluoride. Beyond its medical and culinary uses, N2O is a potent greenhouse gas and contributes to stratospheric ozone depletion.