Atmospheric CFC-11, CFC-12, CFC-113, CCl4 and SF6 Histories (1910-2014)

(updated January 7, 2014)

John Bullister (NOAA/PMEL, John L. Bullister@noaa.gov)

1. Details for CFC-11, CFC-12, CFC-113 and CCl4

The initiation of global atmospheric monitoring programs for CFC-11, CFC-12, CFC-113 and CCl4 began in the late 1970's and early 1980's. Atmospheric concentrations of these compounds prior to this period are derived from estimates of annual industrial production and release of these compounds, with corrections applied based on the atmospheric lifetimes of each compound. Details on the procedures for deriving annual mean CFC-11, CFC-12, CFC-113 and CCl4 concentration values (and estimates of errors) for the period 1910-1998 are provided in Walker et al (2000).

Concentration values for CFC-11, CFC-12, CFC-113 and CCl4 listed in Table 1 from 1910.5 up to 2008.5 are based on a 2009 update ( https://bluemoon.ucsd.edu/pub/cfchist ) of the Walker et al. (2000) results. Information on the calibration scales used at the Scripps Institution of Oceanography (SIO) is also provided at this website. The most recent (2009.5 to 2013.5) concentration values reported in Table 1 are derived from CMDL atmospheric measurements tabulated at the website: ftp://ftp.cmdl.noaa.gov/hats/ in 2013. Because of small (<1%) differences in the CMDL and SIO calibration scales for these compounds, the CMDL concentration values reported from 2009.5 to 2013.5 are not directly used in Table 1. Instead, the yearly changes (in ppt) reported by CMDL for each compound during the period 2008.5 to 2013.5 are added to the SIO concentration values for 2008.5 in Table 1 to derive the yearly concentration values for 2009.5 to 2013.5. The CMDL tabulations available (as of December 2013) at the website ftp://ftp.cmdl.noaa.gov/hats/ only go to November 2013. The 2014.5 concentration values for each compound in Table 1 are extrapolated from the corresponding 2013.5 values, assuming the same changes (in ppt per year) between 2013.5 and 2014.5 as those observed between 2012.5 and 2013.5

There have been several revisions of the calibration scales used at SIO (e.g. SIO93, SIO98, SIO05) for reporting CFC-12, CFC11, CFC-113 and CCl4 concentrations ( https://bluemoon.ucsd.edu/pub/cfchist ). The most recent SIO calibration scale for reporting CFC-12, CFC11, CFC-113 and CCl4 concentrations is the SIO05 scale, which differs slightly from earlier SIO calibration scales. Since most of the measurements of dissolved CFCs in seawater made as part of the World Ocean Circulation Experiment (WOCE) and other major studies have been reported on the earlier SIO98 scale, it has been recommended (Bullister and Tanhua, 2010) for consistency that all future measurements of the concentrations of CFCs in seawater continue to be reported (and stored in data centers) on the SIO98 scale. If desired, seawater CFC concentrations on the SIO98 scale can be converted by users to any other SIO scale using simple multiplicative factors (see https://bluemoon.ucsd.edu/pub/cfchist ).

All of the atmospheric CFC-11, CFC-12, CFC-113 and CCl4 concentration values in Table 1 are reported on the SIO98 calibration scale

2. Details for SF6

A discussion of the atmospheric history of SF6 is provided in Bullister et al. (2006). The initiation of global atmospheric monitoring programs for SF6 began in the 1990's In Table 1, annual atmospheric concentrations of SF6 for the period 1953.5-1994.5 are based on the industrial production and release estimates in Maiss and Brenninkmeijer (1998) (MB1988) for this period. To convert these annual release estimates to atmospheric concentrations, the MB1988 cumulative release value for SF6 in 1995.5 is compared to the measured CMDL ( ftp://ftp.cmdl.noaa.gov/hats/sf6/combined/HATS_global_SF6.txt) NH and SH SF6 atmospheric concentrations in 1995.5. The ratio of the observed CMDL SF6 atmospheric concentration in 1995.5 to the MB1988 cumulative SF6 release for 1995.5 is then used to convert the MB1998 derived cumulative release values for each year (from 1953.5 to 1994.5) to atmospheric concentrations.

Note: In Table 1, atmospheric SF6 concentrations prior to 1953.5 are assumed to be 0. Based on the solubility of SF6 in seawater (Bullister et al, 2002), the 1953.5 atmospheric concentration of SF6 (~0.04 ppt) corresponds to a dissolved SF6 equilibrium concentration of about 0.02 x 10-15 mol/kg seawater. This concentration is at or below the detection limit for dissolved SF6 in seawater using current measurement techniques (Bullister and Wisegarver, 2008).

In Table 1, SF6 values for the period 1995.5 to 2013.5 are based on mid-year measurements of SF6 for the NH and SH reported by CMDL ( ftp://ftp.cmdl.noaa.gov/hats/sf6/combined/HATS_global_SF6.txt). The 2014.5 SF6 concentration values in Table 1 are extrapolated from the corresponding 2013.5 values, assuming the same changes (in ppt per year) between 2013.5 and 2014.5 as those observed between 2012.5 and 2013.5

Because of small differences in the CMDL2006 and SIO2005 SF6 calibration scales [Miller at al., (2008); Rigby et al (2010)], all SF6 concentrations reported in Table 1 have been are converted to the SIO2005 SF6 calibration scale. It has been recommended (Bullister and Tanhua, 2010) that all measurements of the concentrations of SF6 in seawater be reported (and stored in data centers) on the SIO2005 scale

3. Additional Notes

There may be very slight differences (<1%) in some of the atmospheric concentrations of CFC-11, CFC-12, CFC-113, CCl4 and SF6 reported in this version of Table 1 vs. previous versions, due to small revisions and re-calibration of earlier measurements by the CMDL and SIO groups.

Download the Data file and documentation (NH - northern hemisphere, SH - southern hemisphere)

Table 1. Annual mean tropospheric CFC-11, CFC-12, CFC-113, carbon tetrachloride (CCl4) and sulfur hexafluoride (SF6) concentrations in the northern (NH) and southern (SH) hemispheres for the period 1910.5 to 2014.5. The concentrations are expressed as the mixing ratio (mole fraction) of the trace gas in dry air. All concentration values are reported in parts-per-trillion (ppt). CFC-11, CFC-12, CFC-113 and CCl4 concentrations are reported on the SIO98 calibration scale; SF6 concentrations are reported on the SIO2005 calibration scale.

Year CFC11NH CFC11SH CFC12NH CFC12SH CFC113NH CFC113SH CCl4NH CCl4SH SF6NH SF6SH
1910.5 0 0 0 0 0 0 0 0 0 0
1911.5 0 0 0 0 0 0 0.1 0 0 0
1912.5 0 0 0 0 0 0 0.1 0.1 0 0
1913.5 0 0 0 0 0 0 0.1 0.1 0 0
1914.5 0 0 0 0 0 0 0.2 0.1 0 0
1915.5 0 0 0 0 0 0 0.3 0.2 0 0
1916.5 0 0 0 0 0 0 0.5 0.3 0 0
1917.5 0 0 0 0 0 0 0.8 0.5 0 0
1918.5 0 0 0 0 0 0 1 0.7 0 0
1919.5 0 0 0 0 0 0 1.1 0.9 0 0
1920.5 0 0 0 0 0 0 1.2 1.1 0 0
1921.5 0 0 0 0 0 0 1.3 1.2 0 0
1922.5 0 0 0 0 0 0 1.4 1.2 0 0
1923.5 0 0 0 0 0 0 1.7 1.4 0 0
1924.5 0 0 0 0 0 0 1.9 1.6 0 0
1925.5 0 0 0 0 0 0 2.2 1.8 0 0
1926.5 0 0 0 0 0 0 2.5 2.1 0 0
1927.5 0 0 0 0 0 0 2.8 2.4 0 0
1928.5 0 0 0 0 0 0 3.1 2.7 0 0
1929.5 0 0 0 0 0 0 3.6 3 0 0
1930.5 0 0 0 0 0 0 4.2 3.5 0 0
1931.5 0 0 0 0 0 0 4.8 4.1 0 0
1932.5 0 0 0 0 0 0 5.4 4.6 0 0
1933.5 0 0 0 0 0 0 6 5.2 0 0
1934.5 0 0 0 0 0 0 6.8 5.8 0 0
1935.5 0 0 0 0 0 0 7.8 6.6 0 0
1936.5 0 0 0.1 0 0 0 8.9 7.5 0 0
1937.5 0 0 0.1 0.1 0 0 10.3 8.6 0 0
1938.5 0 0 0.2 0.1 0 0 11.6 9.9 0 0
1939.5 0 0 0.3 0.2 0 0 12.9 11.1 0 0
1940.5 0 0 0.4 0.3 0 0 14.4 12.4 0 0
1941.5 0 0 0.5 0.4 0 0 16.2 14 0 0
1942.5 0 0 0.7 0.5 0 0 18.5 15.8 0 0
1943.5 0 0 0.9 0.7 0 0 21.2 18 0 0
1944.5 0 0 1.2 0.9 0 0 24.2 20.5 0 0
1945.5 0.1 0 1.7 1.2 0 0 26.7 23.2 0 0
1946.5 0.1 0.1 2.3 1.7 0 0 28.2 25.3 0 0
1947.5 0.1 0.1 3.4 2.4 0 0 30.1 27.1 0 0
1948.5 0.2 0.1 4.8 3.4 0 0 32.5 29.2 0 0
1949.5 0.4 0.2 6.1 4.7 0 0 34.2 31.2 0 0
1950.5 0.7 0.4 7.6 6 0 0 35.6 32.9 0 0
1951.5 1.01 0.7 9.2 7.4 0 0 37.3 34.4 0 0
1952.5 1.51 1.01 11 9 0 0 38.4 35.9 0 0
1953.5 2.21 1.51 12.8 10.7 0 0 39.3 37 0.042 0.039
1954.5 3.02 2.21 15 12.6 0 0 39.7 37.8 0.043 0.039
1955.5 4.12 3.02 17.4 14.7 0 0 40.1 38.3 0.043 0.04
1956.5 5.33 4.02 20.2 17.1 0 0 40.4 38.7 0.044 0.041
1957.5 6.83 5.23 23.4 19.9 0 0 40.6 39 0.046 0.042
1958.5 8.14 6.53 26.8 23 0 0 41.5 39.5 0.048 0.044
1959.5 9.45 7.84 30.5 26.3 0 0 42.6 40.3 0.051 0.047
1960.5 11.06 9.15 35 30.1 0 0 43.7 41.2 0.055 0.051
1961.5 13.27 10.85 40 34.4 0.1 0.1 44.7 42.2 0.061 0.056
1962.5 16.18 13.07 45.8 39.4 0.3 0.1 45.9 43.3 0.068 0.062
1963.5 19.6 15.78 52.5 45.1 0.5 0.3 47.6 44.5 0.078 0.071
1964.5 23.72 19.2 60.4 51.8 0.8 0.5 49.4 46.1 0.091 0.084
1965.5 28.44 23.12 69.3 59.5 1.1 0.8 50.9 47.7 0.109 0.1
1966.5 33.67 27.64 79.2 68.2 1.49 1.1 53 49.3 0.131 0.12
1967.5 39.4 32.66 90.3 77.9 1.99 1.49 55.8 51.4 0.155 0.142
1968.5 46.03 38.29 102.8 88.8 2.69 1.99 59.1 54.1 0.181 0.166
1969.5 53.77 44.82 116.8 101.1 3.39 2.59 63.4 57.4 0.207 0.19
1970.5 62.41 52.26 132 114.7 4.18 3.29 69.3 61.7 0.235 0.215
1971.5 72.06 60.7 148.4 129.6 5.18 4.08 74.9 67 0.266 0.243
1972.5 82.71 69.95 166.1 145.7 6.27 5.08 77.6 71.4 0.301 0.276
1973.5 94.87 80.4 185.8 163.3 7.47 6.18 79.7 74.3 0.341 0.312
1974.5 108.34 92.16 207.1 182.5 8.96 7.37 83.2 77.2 0.386 0.354
1975.5 121.41 104.72 228.2 202.9 10.66 8.76 85.2 80 0.438 0.401
1976.5 133.97 117.09 248.1 223.2 12.45 10.36 87 82.1 0.501 0.459
1977.5 145.93 129.35 266.9 242.7 14.64 12.25 89.8 84.4 0.579 0.531
1978.5 156.58 140.8 284.3 261.2 16.93 14.34 91.9 86.7 0.665 0.61
1979.5 168.34 148.74 306.1 273.5 19.62 16.63 93.3 88.6 0.766 0.703
1980.5 176.68 159.3 323.2 292.3 22.61 19.32 94.9 89.6 0.887 0.813
1981.5 184.32 167.84 339.6 308.8 25.9 22.21 96.4 90.8 1.011 0.927
1982.5 191.46 176.08 353.4 325.5 29.18 25.3 97.5 92.3 1.141 1.046
1983.5 199.3 184.52 369 342.6 32.97 28.09 98.5 93.5 1.273 1.167
1984.5 208.04 192.46 385.7 359.4 37.85 31.37 99.8 95.1 1.409 1.292
1985.5 217.99 202.01 403.4 378.2 43.92 35.96 100.5 96.6 1.562 1.432
1986.5 229.35 211.36 424.3 396.5 48.31 40.94 101.9 98.2 1.722 1.579
1987.5 241.61 222.21 444 416.3 55.68 47.01 102.5 100 1.892 1.735
1988.5 252.86 233.27 465.4 435.8 63.55 53.29 103.5 100.6 2.063 1.892
1989.5 259.3 242.11 483.6 454.4 69.72 59.66 104.4 101.1 2.237 2.051
1990.5 265.83 251.06 497.7 472.7 75.6 66.14 104.9 102.3 2.427 2.225
1991.5 268.24 256.68 506 487.3 80.98 71.31 105.5 102.5 2.64 2.42
1992.5 268.14 260.8 516.3 498.3 83.96 77.19 104.9 101.9 2.868 2.629
1993.5 269.55 262.51 523.2 507 84.36 79.58 104 101.1 3.104 2.846
1994.5 269.65 263.72 528.5 514.8 84.46 81.27 103 100.3 3.35 3.071
1995.5 268.34 263.22 533.4 521 84.36 82.17 102.1 99.6 3.6 3.3
1996.5 266.93 262.91 537.3 526.5 84.06 82.67 101.1 98.6 3.861 3.56
1997.5 265.73 262.01 540.1 530.8 83.57 82.67 100.2 98 4.08 3.824
1998.5 264.52 261.01 542.9 534.3 83.17 82.47 99.2 97 4.262 4.026
1999.5 263.12 259.9 544.4 537.2 82.47 81.97 98.2 96.2 4.485 4.262
2000.5 261.71 258.29 545.9 539 81.87 81.37 97.3 95.4 4.69 4.471
2001.5 260 256.98 546.5 540.6 81.18 80.78 96.3 94.4 4.909 4.657
2002.5 258.19 255.08 546.7 541.3 80.48 79.98 95.3 93.6 5.135 4.887
2003.5 256.18 253.27 546.7 541.6 79.88 79.38 94.3 92.5 5.36 5.081
2004.5 253.97 251.36 545.7 541.5 79.08 78.78 93.3 91.7 5.58 5.305
2005.5 251.96 249.15 544.9 540.7 78.49 78.09 92.4 90.8 5.795 5.513
2006.5 249.55 247.34 543.1 539.8 77.69 77.59 91.3 89.7 6.034 5.749
2007.5 247.54 245.03 541.1 538.1 76.99 76.79 90.4 88.9 6.324 6.028
2008.5 245.63 243.12 538.6 536.2 76.29 76.2 89.3 87.7 6.613 6.286
2009.5 243.61 241.07 536.11 533.53 75.81 75.49 87.68 85.99 6.876 6.576
2010.5 241.33 239.19 533.3 530.94 75 74.82 86.6 85.21 7.191 6.856
2011.5 239.41 236.92 530.67 528.47 74.34 74.09 85.16 83.67 7.439 7.159
2012.5 236.6 234.6 527.16 525.88 73.65 73.46 84.08 82.62 7.715 7.424
2013.5 235.08 233.29 525.26 523.48 72.99 73.01 82.78 81.62 8.066 7.754
2014.5 233.55 231.97 523.36 521.08 72.33 72.56 81.49 80.62 8.417 8.084

4. References

  • Bullister, J. L., D. P. Wisegarver, and R. E. Sonnerup. 2006. Sulfur hexafluoride as a transient tracer in the North Pacific Ocean. Geophys. Res. Lett., 33, L18603, doi: 10.1029/2006GL026514.
  • Bullister, J.L., and T. Tanhua. 2010. Sampling and measurement of chlorofluorocarbons and sulfur hexafluoride in seawater. In The GO-SHIP Repeat Hydrography Manual: A Collection of Expert Reports and Guidelines. E.M. Hood, C.L. Sabine, and B.M. Sloyan (eds.), IOCCP Report Number 14, ICPO Publication Series Number 134. Available online at http://www.go-ship.org/HydroMan.html.
  • Maiss, M., and C. A. M. Brenninkmeijer. 1998. Atmospheric SF6, trends sources and prospects. Environ. Sci. Tech., 32:3077-3086.
  • Miller, B. R., R. F. Weiss, P. K. Salameh, T. Tanhua, B. R. Greally, J. Muhle, and P. G. Simmonds. 2008. Medusa: A sample preconcentration and GC/MS detector system for in situ measurements of atmospheric trace halocarbons, hydrocarbons, and sulfur compounds. Anal. Chem., 80, 1536–1545, doi:10.1021/ac702084k, http://pubs.acs.org/doi/abs/10.1021/ac702084k, 2008.
  • Walker, S. J., R. F. Weiss, and P. K. Salameh. 2000. Reconstructed histories of the annual mean atmospheric mole fractions for the halocarbons CFC-11 CFC-12, CFC-113, and carbon tetrachloride. J. Geophys. Res., 105(C6), 14,285–14,296, doi:10.1029/1999JC900273.
  • Rigby, M., J. Mühle, B. R. Miller, R. G. Prinn, P. B. Krummel, L. P. Steele, P. J. Fraser, P. K. Salameh, C. M. Harth, R. F. Weiss, B. R. Greally, S. O'Doherty, P. G. Simmonds, M. K. Vollmer, S. Reimann, J. Kim, K. -R. Kim, H. J. Wang, J. G. J. Olivier, E. J. Dlugokencky, G. S. Dutton, B. D. Hall, J.W. and Elkins. 2010. History of atmospheric SF6 from 1973 to 2008, Atmos. Chem. Phys., 10, 10305-10320, www.atmos-chem-phys.net/10/10305/2010/, doi:10.5194/acp-10-10305-2010.

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