#Science #ScienceNews #laughing_gas #nitrous_oxide #dinitrogen_oxide #dinitrogen_monoxide #rocketry Nitrous oxide, commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula N2O. At room temperature, it is a colorless non-flammable gas and has a slightly sweet scent and taste. At elevated temperatures, nitrous oxide is a powerful oxidizer similar to molecular oxygen. Nitrous oxide has significant medical uses, especially in surgery and dentistry, for its anesthetic and pain-reducing effects. Its colloquial name, "laughing gas", coined by Humphry Davy, is due to the euphoric effects upon inhaling it, a property that has led to its recreational use as a dissociative anesthetic. It is on the World Health Organization's List of Essential Medicines. It is also used as an oxidizer in rocket propellants, and in motor racing to increase the power output of engines. Nitrous oxide's atmospheric concentration reached 333 parts per billion (ppb) in 2020, increasing at a rate of about 1 ppb annually. It is a major scavenger of stratospheric ozone, with an impact comparable to that of CFCs. Global accounting of N2O sources and sinks over the decade ending 2016 indicates that about 40% of the average 17 TgN/yr (teragrams, or million metric tons, of nitrogen per year) of emissions originated from human activity, and shows that emissions growth chiefly came from expanding agriculture and industry sources within emerging economies. Being the third most important long-lived greenhouse gas, nitrous oxide also substantially contributes to global warming. Nitrous oxide is used as a propellant and has a variety of applications from rocketry to making whipped cream. It is used as a recreational drug for its potential to induce a brief "high"; most recreational users are unaware of its neurotoxicity and potential to cause neurological damage.