Criteria air pollutants gases threaten both the public health and the public welfare, and that greenhouse gas emissions from motor vehicles contribute to that threat. This final action has two distinct 'findings,' which are: 1) The 'Endangerment Finding' in which the Administrator found that the mix of atmospheric concentrations of six key, well-mixed greenhouse gases threatens both the public health and the public welfare of current and future generations. These six greenhouse gases are: carbon dioxide (CO), methane (CH), nitrous oxide (NO), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF). These greenhouse gases in the atmosphere constitute the "air pollution" that threatens both
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