Editing Carbon monoxide (section)

===Atmospheric presence===
[[File:Carbon Monoxide.ogv|thumb|The streak of red, orange, and yellow across [[South America]], [[Africa]], and the [[Atlantic Ocean]] in this animation points to high levels of carbon monoxide on September 30, 2005.]]
[[File:Carbon Monoxide concentrations in spring..jpg|thumb|Carbon monoxide concentrations in Northern Hemisphere spring as measured with the MOPITT instrument]]

Carbon monoxide (CO) is present in small amounts (about 80 [[Parts per billion|ppb]]) in the [[Atmosphere of Earth|Earth's atmosphere]]. Most of the rest comes from chemical reactions with [[organic compound]]s emitted by human activities and natural origins due to [[photochemistry|photochemical]] reactions in the [[troposphere]] that generate about 5 × 10<sup>12</sup> kilograms per year.<ref name="Weinstock-1972">{{Cite journal|last1=Weinstock|first1=B.|last2=Niki|first2=H.|year=1972|title=Carbon Monoxide Balance in Nature|journal=Science|volume=176|issue=4032|pages=290–2|bibcode=1972Sci...176..290W|doi=10.1126/science.176.4032.290|pmid=5019781|s2cid=25223868}}</ref> Other natural sources of CO include volcanoes, [[forest fires|forest]] and [[bushfire]]s, and other miscellaneous forms of combustion such as [[fossil fuel]]s.<ref name="Seinfeld2006">{{cite book|last1=Seinfeld|first1=John|title=Atmospheric Chemistry and Physics: From Air Pollution to Climate Change|last2=Pandis|first2=Spyros|date=2006|publisher=John Wiley & Sons|isbn=978-0-471-72018-8}}</ref> Small amounts are also emitted from the ocean, and from geological activity because carbon monoxide occurs dissolved in molten volcanic rock at high pressures in the Earth's [[mantle (geology)|mantle]].<ref>{{Cite book|author1=Sigel, Astrid|url=https://books.google.com/books?id=kcllhZcy53cC&pg=PA243|title=Metal-Carbon Bonds in Enzymes and Cofactors|author2=Sigel, Roland K. O.|publisher=Royal Society of Chemistry|year=2009|isbn=978-1-84755-915-9|page=243}}</ref> Because natural sources of carbon monoxide vary from year to year, it is difficult to accurately measure natural emissions of the gas.

Carbon monoxide has an indirect effect on [[radiative forcing]] by elevating concentrations of direct [[greenhouse gas]]es, including [[methane]] and [[troposphere|tropospheric]] [[ozone]]. CO can react chemically with other atmospheric constituents (primarily the [[hydroxyl]] [[Radical (chemistry)|radical]], <sup>•</sup>OH) that would otherwise destroy methane.<ref>{{Cite book|author=White, James Carrick|url=https://books.google.com/books?id=gnaNHeU4rgQC&pg=PA106|title=Global climate change linkages: acid rain, air quality, and stratospheric ozone|publisher=Springer|year=1989|isbn=978-0-444-01515-0|page=106|display-authors=etal}}</ref> Through natural processes in the atmosphere, it is oxidized to [[carbon dioxide]] and ozone. Carbon monoxide is short-lived in the atmosphere (with an average lifetime of about one to two months), and spatially variable in concentration.<ref>{{cite web|last=Drummond|first=James|date=February 2, 2018|title=MOPITT, Atmospheric Pollution, and Me: A Personal Story|url=http://bulletin.cmos.ca/mopitt-atmospheric-pollution/|access-date=August 1, 2018|publisher=Canadian Meteorological and Oceanographic Society}}</ref>

Due to its long lifetime in the mid-troposphere, carbon monoxide is also used as a tracer for pollutant plumes.<ref>{{cite journal|last1=Pommier|first1=M.|last2=Law|first2=K. S.|last3=Clerbaux|first3=C.|last4=Turquety|first4=S.|last5=Hurtmans|first5=D.|last6=Hadji-Lazaro|first6=J.|last7=Coheur|first7=P.-F.|last8=Schlager|first8=H.|last9=Ancellet|first9=G.|last10=Paris|first10=J.-D.|last11=Nédélec|first11=P.|year=2010|title=IASI carbon monoxide validation over the Arctic during POLARCAT spring and summer campaigns|url=https://hal.archives-ouvertes.fr/hal-00491181|journal=Atmospheric Chemistry and Physics|volume=10|issue=21|pages=10655–10678|bibcode=2010ACP....1010655P|doi=10.5194/acp-10-10655-2010|doi-access=free|last15=Bernath|first15=P.|first14=J. S.|last14=Holloway|first13=J. R.|last13=Podolske|first12=G. S.|last12=Diskin}}</ref>