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
Industrial gas nitrogen (1772), nitrous oxide (1772) , oxygen (1773) , ammonia (1774), chlorine (1774), methane (1776), hydrogen sulfide (1777), carbon monoxide (1800), hydrogen chloride (1810), acetylene (1836), helium (1868) fluorine (1886), argon (1894), krypton, neon and xenon (1898) Carbon dioxide, hydrogen, nitrous oxide, oxygen, ammonia, chlorine, sulfur dioxide and manufactured fuel gas were already being used during the 19th century, and mainly had uses in food, refrigeration, medicine, and for fuel and gas lighting. For example, carbonated water was being made from 1772 and commercially from 1783, chlorine was first used to bleach textiles in 1785 and nitrous oxide was first