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
Carbon dioxide combustion of all carbon-based fuels, such as methane (natural gas), petroleum distillates (gasoline, diesel, kerosene, propane), coal, wood and generic organic matter produces carbon dioxide and, except in the case of pure carbon, water. As an example, the chemical reaction between methane and oxygen: It is produced by thermal decomposition of limestone, by heating (calcining) at about , in the manufacture of quicklime (calcium oxide, ), a compound that has many industrial uses: Iron is reduced from its oxides with coke in a blast furnace, producing pig iron and carbon dioxide: Carbon dioxide is a byproduct of the industrial production