Nitrous oxide, also known as dinitrogen oxide or dinitrogen monoxide, is a chemical compound with chemical formula N2O. Under room conditions, it is a colourless non-inflammable gas, with a pleasant, slightly-sweet odor. It is used in surgery and dentistry for its anaesthetic and analgesic effects, where it is commonly known as laughing gas due to the euphoric effects of inhaling it. It is also used as a means to enable short periods of extreme high performance in automobile internal combustion engines by introducing extra oxygen into the intake charge which in turn allows a greater amount of fuel to be added and converted into energy and thereby greatly increasing the power produced by the engine. Nitrous oxide is present in the atmosphere where it acts as a powerful greenhouse gas.