Carbon dioxide equivalent of carbon dioxide. Equivalent (e) is the concentration of that would cause the same level of radiative forcing as a given type and concentration of greenhouse gas. Examples of such greenhouse gases are methane, perfluorocarbons, and nitrous oxide. e is expressed as parts per million by volume, ppmv. Carbon dioxide equivalent Carbon dioxide equivalent (CDE) and equivalent carbon dioxide (e and eq) are two related but distinct measures for describing how much global warming a given type and amount of greenhouse gas may cause, using the functionally equivalent amount or concentration of carbon dioxide () as the reference. Carbon dioxide
Nitrous oxide and inhibit pain signalling. Exactly how causes the release of endogenous opioid peptides remains uncertain. Nitrous oxide is a colourless, non-toxic gas with a faint, sweet odour. Nitrous oxide supports combustion by releasing the dipolar bonded oxygen radical, thus it can relight a glowing splint. The above reaction is the route adopted by the commercial chemical industry to produce azide salts, which are used as detonators. The gas was first synthesised in 1772 by English natural philosopher and chemist Joseph Priestley, who called it "phlogisticated nitrous air" (see phlogiston) or "inflammable nitrous air". Priestley published his discovery in the book