Nitrous Oxide

Commonly known as laughing gas, nitrous oxide has been consumed by humans since the 1700s, when it was first isolated by Joseph Priestley. It was initially used for public entertainment, much in the same way that ‘hippy crack’ is consumed now, as attested to by the empty bulbs and balloons that can be found on London streets on a Sunday morning. Inhaling the gas can give feelings of euphoria or relaxation, fits of giggles, sound distortions and hallucinations and, as first noticed by dental surgeon Horace Wells in the 1840s, relief from pain. This was the beginning of its use as an anaesthetic in dentistry, surgery and childbirth. It is also used to whip cream because it is bacteriostatic, dissolves in the cream easily and does not cause the cream to oxidize in the can. It can also be injected into a car’s engine during motor racing to give it more available oxygen for combustion and therefore more power. 

 

But is this substance all laughs? Aside from being an asphyxiation hazard, nitrous oxide also contributes to global warming. We tend to focus on carbon dioxide when we talk about greenhouse gases, but nitrous oxide, along with methane and fluorinated gases like sulphur hexafluoride (SF₆), have a much greater impact on global warming.

 

All of these gases enhance the greenhouse effect in that same way as CO₂, by capturing reradiated infrared radiation from the earth’s atmosphere and warming up the lower atmosphere. However although nitrous and SF₆ are present in smaller concentrations, they trap heat very effectively, making them high global-warming potential (GWP) gases. Nitrous oxide is 300 times more warming than CO₂, it lasts a very long time in the atmosphere, and the process to remove it from the atmosphere also depletes ozone. Globally, about 40% of N₂O emissions come from human activities including agriculture, fuel consumption, wastewater management and as a by-product of industrial processes like the production of nitric acid, which is used to make synthetic fertilizers.

 

These bulbs were collected as part of a Materials Library display for our Gases Open Day.