Natural gas is an odorless, nontoxic, gaseous mixture of hydrocarbons, mostly (typically 85% to 95%) methane (CH4) and accounts for about one-fourth of the energy used in the U.S.A. The mixture of hydrocarbon gases occurs with petroleum deposits deep in the earth. This mixture may contain varying quantities of ethane, propane, butane, pentane, nitrogen, carbon dioxide and other gases including helium in some sources. It is used by itself or mixed with various enrichments of oxygen as a fuel, used as the most common and cheapest way to produce hydrogen, or used in the manufacture of organic compounds.
Methane is the shortest hydrocarbon chain with 1 carbon atom for every 4 hydrogen atoms. This means, when combusted, natural gas results in the lowest possible carbon monoxide emission than all other hydrocarbon fuels (gasoline, Diesel, propane, etc). Carbon monoxide becomes carbon dioxide when exposed to the atmosphere and sunlight and carbon dioxide is targeted as a GHG that affects the ozone layer protecting the earth from harmful rays from the sun. Gasoline and Diesel is closer to a 2 to 1 ratio of carbon to energy, resulting in a higher level of carbon monoxide as a product of combustion.