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 and retains adequate mental faculties to respond to questions and instructions from the dentist. Inhalation of nitrous oxide is used frequently to relieve pain associated with childbirth, trauma, oral surgery, and acute coronary syndrome (includes heart attacks). Its use during labour has been shown to be a safe and effective aid for birthing women. Its use for acute coronary syndrome is of unknown benefit. In Britain and Canada, Entonox and Nitronox are used commonly by ambulance crews (including unregistered practitioners) as a rapid and highly effective analgesic gas. 50% nitrous oxide can be considered for use by trained non-professional first