Sampling Sites	Click to rotate molecule	Concentration Units (Click to see graph)	Global Warming Potential*	Atmospheric lifetime (years)*
Carbon dioxide CO2		ppm	1	120
Methane CH4		ppb	23	12
Hydrogen H2		ppb
Nitrous oxide N2O		ppb	296	114
Carbon monoxide CO		ppb	~2	0.25
Trichlorofluoromethane CCl3F CFC-11		ppt	4,600	45
Dichlorodifluoromethane CF2Cl2 CFC-12		ppt	10,600	100
Trichlorotrifluoroethane CCl2FCClF2 CFC-113		ppt	6,000	85
Carbon tetrachloride CCl4		ppt	1,800	35
Chloroform CHCl3		ppt	30	0.51
Dichloromethane CH2Cl2		ppt	10	0.46
Methyl chloride CH3Cl		ppt	16	1.3
Tetrachloroethene Cl2C=CCl2		ppt
Methyl chloroform CH3CCl3		ppt	140	4.8
Chlorodifluoromethane CHClF2 HCFC-22		ppt	1,700	11.9
Chlorodifluoroethane CH3CClF2 HCFC-142b		ppt	2,400	19
Dichlorofluoroethane CH3CFCl2 HCFC-141b		ppt	700	9.3
Tetrafluoroethane CH2FCF3 HFC-134a		ppt	1,300	13.8
Perfluoroethane CF3CF3		ppt	10,000	11,900
Bromochlorodifluoromethane CBrClF2 Halon-1211		ppt	1,300	11
Dibromotetrafluoroethane CBrF2CBrF2 Halon-2402		ppt		20
Bromotrifluoromethane CBrF3 Halon-1301		ppt	6,900	65
Sulfur hexafluoride SF6		ppt	22,200	3,200
Trifluoromethyl sulfur pentafluoride CF3SF5		ppt	~17,500	~1000

ppm = parts per million (10⁶), ppb = parts per billion (10⁹), ppt = parts per trillion (10¹²).

^* The Global Warming Potential (GWP) is typically used to contrast different greenhouse gases and provides a simple measure of the radiative effects of various greenhouse gases relative to CO₂ defined as 1. Atmospheric lifetimes is the general term used for the "adjustment time", the time-scale characterizing the decay of an instantaneous pulse input into the reservoir. One hundred year time horizon GWPs and atmospheric lifetimes taken from Table 6.7, Climate Change 2001: The Scientific Basis . J.T. Houghton, Y. Ding, D. J. Griggs, M. Noguer, P. J. van der Linden, X. Da, K. Maskell, and C. A. Johnson for the Intergovernmental Panel on Climate Change. See also http://cdiac.esd.ornl.gov/pns/current_ghg.html

References