Sampling Sites

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    Concentration Units (Click to see graph)

    Ozone Depletion Potential*

    Atmospheric lifetime (years)**
    Ozone
    O3

    ppm

    hours
    Trichlorofluoromethane
    CCl3F
    CFC-11

    ppt

    1.0

    45
    Dichlorodifluoromethane
    CF2Cl2
    CFC-12

    ppt

    1.0

    100

    Trichlorotrifluoroethane
    CCl2FCClF2
    CFC-113

    ppt

    1.0

    85
    Carbon tetrachloride
    CCl4

    ppt

    0.73

    26
    Chloroform
    CHCl3

    ppt

    0.51
    Dichloromethane
    CH2Cl2

    ppt

    0.38
    Methyl chloride
    CH3Cl

    ppt
    0.02
    1.0
    Tetrachloroethene
    Cl2C=CCl2
    perchloroethylene (perc)

    ppt
    Methyl chloroform
    CH3CCl3

    ppt

    0.12

    5

    Chlorodifluoromethane
    CHClF2
    HCFC-22

    ppt

    0.05

    12
    Chlorodifluoroethane
    CH3CClF2
    HCFC-142b

    ppt
    0.07
    17.9

    Dichlorofluoroethane
    CH3CFCl2
    HCFC-141b

    ppt
    0.12
    9.3

    Difluoroethane
    CH3CHF2
    HFC-152a

    ppt
    1.4

    Tetrafluoroethane
    CH2FCF3
    HFC-134a

    ppt
    14

    Fluoroform
    CHF3
    HFC-23

    ppt
    270
    Perfluoroethane
    CF3CF3
    PFC-116

    ~ 4 ppt

    10,000

    Bromochlorodifluoromethane
    CBrClF2
    Halon-1211

    ppt

    7.1

    16

    Methylbromide
    CH3Br

    ppt

    0.51

    0.7
    Dibromotetrafluoroethane
    CBrF2CBrF2
    Halon-2402

    ppt

    11.5

    20
    Bromotrifluoromethane
    CBrF3
    Halon-1301

    ppt

    16

    65
    Sulfur hexafluoride
    SF6

    ppt

    3,200
    Trifluoromethyl sulfur pentafluoride
    CF3SF5

    ppt

    800
    Nitrogen trifluoride
    NF3

    ppt

    740
    Carbon tetrafluoride
    CF4

    ~80 ppt

    50,000

    * The Ozone Depletion Potentials (ODP) is used to contrast different gases and provides a simple measure of the expected impact on ozone per unit mass emission of a gas relative to CFC-11 defined as 1.0; values are from Table 8-1, Scientific Assessment of Ozone Depletion: 2006, World Meteorological Organization (WMO) Global Ozone Research and Monitoring Program -- Report No. 50 (2007). See also US EPA Ozone-depleting Substances.

    ** Atmospheric lifetime is used to characterize the decay of an instanenous pulse input to the atmosphere, and represents the time the input would take to decay to 0.368 (1/e) of its original value. Values are from Table 2.14, Intergovernmental Panel on Climate Change, Climate Change 2007: The Physical Science Basis, IPCC WG1 AR4 Report. See also http://cdiac.esd.ornl.gov/pns/current_ghg.html

    References

    Ozone Depleting Molecules | Ozone Hole | ChemConnections