Editing Compressed natural gas (section)

== Advantages ==
[[File:Emt-gas-2.jpg|thumb|right|A CNG-powered bus being refueled in Madrid, Spain.]]
* [[Natural gas vehicle]]s have lower maintenance costs than other hydrocarbon-fuel-powered vehicles.
* CNG fuel systems are sealed, preventing fuel losses from spills or evaporation.
* Increased life of lubricating oils, as CNG does not contaminate and dilute the crankcase oil.
* Being a gaseous fuel, CNG mixes easily and evenly in air.
* CNG is less likely to ignite on hot surfaces, since it has a high auto-ignition temperature (540&nbsp;°C), and a narrow range (5–15 percent) of [[flammability]].<ref name=GAIL>{{Cite web|url=http://www.gailonline.com/gailnewsite/businesses/citygasdistributionadvantage.html |title=GAIL |access-date=2009-10-25 |url-status=dead |archive-url=https://web.archive.org/web/20091231100505/http://gailonline.com/gailnewsite/businesses/citygasdistributionadvantage.html |archive-date=2009-12-31}}</ref>
* CNG-powered vehicles are considered to be safer than petrol-powered vehicles.<ref>{{Cite web|url=http://www.cleanvehicle.org/committee/technical/PDFs/Web-TC-TechBul2-Safety.pdf|title=How Safe are Natural Gas Vehicles?|publisher=Clean Vehicle Education Foundation|access-date=2008-05-08|url-status=dead|archive-url=https://web.archive.org/web/20080528041023/http://www.cleanvehicle.org/committee/technical/PDFs/Web-TC-TechBul2-Safety.pdf|archive-date=2008-05-28}}</ref><ref>{{Cite web|url=http://alternativefuels.about.com/od/naturalgaspropane/a/safenaturalgas.htm|title=How Safe is Natural Gas?|website=Alternativefuels.about.com|access-date=2008-05-08|archive-date=2016-09-18|archive-url=https://web.archive.org/web/20160918224004/http://alternativefuels.about.com/od/naturalgaspropane/a/safenaturalgas.htm|url-status=dead}}</ref><ref>{{Cite web|url=http://www.firetrainingresources.net/items/CNGAutoFire-FIREFIGHTERNEARMISScompressedpics.pdf|title=Fighting CNG fires|website=Firetrainingsources.net|access-date=2008-05-08|url-status=usurped|archive-url=https://web.archive.org/web/20080528041023/http://www.firetrainingresources.net/items/CNGAutoFire-FIREFIGHTERNEARMISScompressedpics.pdf|archive-date=2008-05-28}}</ref>
* ''Less pollution and more efficiency:''
** CNG emits significantly less pollution directly than petrol or oil when combusted (e.g., [[unburned hydrocarbon]]s (UHC), [[carbon monoxide]] (CO), [[nitrogen oxide]]s (NO<sub>X</sub>), [[sulfur oxide]]s (SO<sub>x</sub>) and PM ([[Atmospheric particulate matter|particulate matter]])). For example, an engine running on petrol for 100&nbsp;km produces 22&nbsp;kilograms of {{CO2}}, while covering the same distance on CNG emits only 16.3&nbsp;kilograms of {{CO2}}.<ref>{{Cite web|url=http://naturalgas.org/environment/naturalgas.asp |title=Archived copy |access-date=2012-11-25 |url-status=dead |archive-url=https://web.archive.org/web/20121117000137/http://www.naturalgas.org/environment/naturalgas.asp |archive-date=2012-11-17}}</ref>{{Better source needed|date=November 2015}}<!-- NatGas industry is not an independent source. Comparison depends on pollution standard -->
** The [[Life cycle assessment|lifecycle]] greenhouse gas emissions for CNG compressed from California's pipeline natural gas is given a value of 67.70&nbsp;grams of [[carbon dioxide equivalent|{{CO2}}-equivalent]] per [[megajoule]] (gCO<sub>2</sub>e/MJ) by CARB (the [[California Air Resources Board]]), approximately 28 percent lower than the average petrol fuel in that market (95.86 gCO<sub>2</sub>e/MJ).
** CNG produced from landfill biogas was found by CARB to have the lowest greenhouse gas emissions of any fuel analyzed, with a value of 11.26 gCO<sub>2</sub>e/MJ (more than 88 percent lower than conventional petrol) in the [[low-carbon fuel standard]] that went into effect on January 12, 2010.<ref>{{Cite web |url=http://www.arb.ca.gov/fuels/lcfs/121409lcfs_lutables.pdf |title=Table 6. Carbon Intensity Lookup Table for Gasoline and Fuels that Substitute for Gasoline. |website=Arb.ca.gov |access-date=2016-07-17 |archive-date=2017-11-20 |archive-url=https://web.archive.org/web/20171120105610/https://www.arb.ca.gov/fuels/lcfs/121409lcfs_lutables.pdf |url-status=dead }}</ref>
** Due to lower carbon dioxide emissions, switching to CNG can help mitigate [[greenhouse gas emission]]s.<ref name=GAIL /> However, natural gas leaks (both in the direct use and in the production and delivery of the fuel) represent an increase in greenhouse gas emissions. The ability of CNG to reduce greenhouse gas emissions over the entire fuel lifecycle will depend on the source of the natural gas and the fuel it is replacing.