Nitrous oxide inside the cells, by a process catalyzed by the enzyme nitrous oxide reductase. Nitrous oxide has significant global warming potential as a greenhouse gas. On a per-molecule basis, considered over a 100-year-period, nitrous oxide has 298 times the atmospheric heat-trapping ability of carbon dioxide (), however, because of its low concentration (less than 1/1000 of that of ), its contribution to the greenhouse effect is less than one-third that of carbon dioxide, and also less than water vapour and methane. On the other hand, since 38% or more of the entering the atmosphere is the result of human activity, and
Nitrous oxide Because nitrous oxide is minimally metabolised in humans (with a rate of 0.004%), it retains its potency when exhaled into the room by the patient, and can pose an intoxicating and prolonged exposure hazard to the clinic staff if the room is poorly ventilated. Where nitrous oxide is administered, a continuous-flow fresh-air ventilation system or scavenger system is used to prevent a waste-gas buildup. The National Institute for Occupational Safety and Health recommends that workers' exposure to nitrous oxide should be controlled during the administration of anaesthetic gas in medical, dental, and veterinary operators. It set a recommended exposure limit