An atmospheric photochemical source of the persistent greenhouse gas CF4

Details

• Journal Title:
  Geophysical Research Letters
• Personal Author:
  Jubb, Aaron M. ; McGillen, Max R. ; Portmann, Robert W. ; Daniel, John S. ; Burkholder, James B.
• NOAA Program & Office:
  OAR (Oceanic and Atmospheric Research) ; ESRL (Earth System Research Laboratory) ; CSL (Chemical Sciences Laboratory)
• Description:
  A previously uncharacterized atmospheric source of the persistent greenhouse gas tetrafluoromethane, CF4, has been identified in the UV photolysis of trifluoroacetyl fluoride, CF3C(O)F, which is a degradation product of several halocarbons currently present in the atmosphere. CF4 quantum yields in the photolysis of CF3C(O) F were measured at 193, 214, 228, and 248 nm, wavelengths relevant to stratospheric photolysis, to be (75.3 +/- 1) x 10(-4), (23.7 +/- 0.4) x 10(-4), (6.6 +/- 0.2) x 10(-4), and <= 0.4 x 10(-4), respectively. A 2-D atmospheric model was used to estimate the contribution of the photochemical source to the global CF4 budget. The atmospheric photochemical production of CF4 from CF3CH2F (HFC-134a), CF3CHFCl (HCFC-124), and CF3CCl2F (CFC-114a) per molecule emitted was calculated to be (1-2.5) x 10(-5), 1.0 x 10(-4), and 2.8 x 10(-3), respectively. Although CF4 photochemical production was found to be relatively minor at the present time, the identified mechanism demonstrates that long-lived products with potential climate impacts can be formed from the atmospheric breakdown of shorter-lived source gases.
• Source:
  Geophysical Research Letters, 42(21), 9505-9511.
• DOI:
  https://doi.org/10.1002/2015gl066193
• Document Type:
  Journal Article
• Rights Information:
  Other
• Compliance:
  Submitted
• Main Document Checksum:
  urn:sha256:37a22ef52e87e5643709fe4407cd4e7708d22d62181f8c014cb096c475365387
• Download URL:
  https://repository.library.noaa.gov/view/noaa/21651/noaa_21651_DS1.pdf
• File Type:
  [PDF - 356.96 KB ]