Laughing gas, N2O, dinitrogen monoxide or to use its older name, nitrous oxide has a range of uses in our society. Most of these would have to fall into the category of non-essential. Nitrous oxide is well known as a dental anaesthetic gas. Having gas at the dentist though, is much less common nowadays, because of accidents that have happened. There have been occasions where patients have had the wrong percentage of oxygen mixed with the nitrous oxide they were given. The requirement in some states that a fully qualified anaesthetist is present when nitrous oxide is used. It is not as pleasant to be given nitrous oxide as it sounds, it often causes nausea and dizziness. Whipped ice-cream uses nitrous oxide as the gas in the tiny bubbles. Nitrous oxide ice-cream chargers have caused death to individuals who have inhaled the gas directly. Nitrous oxide is not poisonous, but inhaled in large amounts, like this and without any added oxygen, it causes the lungs to collapse. Inhaling nitrous oxide in this way is illegal in many jurisdictions. Accidents have also occurred when people have confused nitrous oxide with the highly poisonous nitric oxide gas. Nitrous oxide is used in rocket fuels and also by custom car enthusiasts to boost the performance of their engines. The nitrous oxide is a more powerful oxidizing agent than the 21% oxygen in the atmosphere. Temperatures in the engines are higher and specially designed valves are necessary to withstand the extra heat. Nitrous oxide is extremely harmful to the atmosphere. It has 250 times the greenhouse gas effect as carbon dioxide. This means that 1 litre of nitrous oxide has the same climate changing effect as 250 litres of carbon dioxide. The quantities of nitrous oxide released to the atmosphere are small, so it still only contributes a small fraction of the total greenhouse effect.