Table 29. GWP-Weighted U.S. Emissions of Hydrofluorocarbons, 
Perfluorocarbons, and Sulfur Hexafluoride, 1990-1998
(Million Metric Tons Carbon Equivalent)

Gas 1990 1991 1992 1993 1994 1995 1996 1997 P1998
Hydrofluorocarbons (HFCs)  
  HFC-23 9.54 8.46 9.70 8.97 8.97 7.85 9.06 8.78 8.65
  HFC-134a 0.20 0.20 0.22 1.02 1.92 3.39 4.83 6.37 6.82
  HFC-125 0.00 0.00 0.18 0.37 1.24 2.15 2.42 2.73 3.01
  HFC-227 0.00 0.00 0.00 0.00 0.70 1.49 1.63 2.09 2.39
  HFC-143a 0.00 0.00 0.00 0.01 0.04 0.09 0.24 0.44 0.62
  HFC-4310 0.00 0.00 0.00 0.00 0.00 0.22 0.37 0.52 0.68
  Other HFCs 0.06 0.03 0.01 0.03 0.03 0.04 0.18 0.36 0.39
    Total 9.80 8.68 10.12 10.39 12.91 15.23 18.72 21.28 22.56
Perfluorocarbons (PFCs)  
  CF4 4.61 4.46 4.03 3.59 3.01 2.95 3.22 3.18 3.09
  C2F6 0.73 0.83 0.88 0.95 1.00 1.10 1.25 1.18 1.13
  C4F10 0.00 0.00 0.00 0.00 0.00 0.05 0.15 0.25 0.25
  PFCs/PFPEs 0.00 0.00 0.00 0.00 0.08 2.48 2.48 2.51 2.51
    Total 5.34 5.29 4.91 4.55 4.09 6.59 7.11 7.12 6.98
Sulfur Hexafluoride 7.30 7.82 8.34 8.93 9.45 9.97 9.97 9.97 9.97
Total Emissions 22.44 21.79 23.37 23.87 26.45 31.80 35.80 38.38 39.51

P = preliminary data.
Sources: 1990-1997: U.S. Environmental Protection Agency, Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-1997, EPA-236-R-99-003 (Washington, DC, April 1999), web site www.epa.gov/globalwarming/inventory/1999-inv.html. 1998: Estimated from methods described in Appendix A. Global warming potentials used to convert emissions to carbon-equivalent basis from Intergovernmental Panel on Climate Change, Climate Change 1995: The Science of Climate Change (Cambridge, UK: Cambridge University Press, 1996), pp. 119 and 121.

Back to Halocarbons and Other Gases