The Reston Groundwater Dating Laboratory

Atmospheric mixing ratios of CFC-11, CFC-12, CFC-113,CFC-13 x 100, SF6 x 100, and SF5CF3 x 1000 for Northern Hemisphere atmosphere.

Data for the construction of the mixing ratios in this figure were obtained from the CMDL/NOAA website URL http://www.cmdl.noaa.gov/ (Elkins, Butler, Thompson, and Montzka, 2003; Montzka et al., 1996 and 1999), from the CDIAC website URL http://cdiac.esd.ornl.gov/ (Walker et al., 2000; Prinn et al., 2000; Cunnold et al., 1997). Data that was used to construct the Northern Hemisphere 1980 to 1990 atmospheric concentrations for CFC-113 were obtained from a number of sources (Busenberg and Plummer, 1993; Wisegarver and Gammon, 1988; Gilpin, 1991; Wang 1993 and 1997; and Tominaga, 1993). The pre-1980's mixing ratios were reconstructed from production and atmospheric release data (Fisher and Midgley, 1993; and AFEAS, 2003, http://www.afeas.org/ ). The USGS CFC Lab Age Dating Group also maintains an air monitoring station at Shenandoah National Park, VA.

Atmospheric mixing ratios of CFC-11, CFC-12, CFC-13, CFC-113, and SF6 in North America (NH) compiled by the USGS CFC Lab Age Dating Group can be downloaded in an excel spreadsheet here.

Air Curves CFCs SF6 3H excel spreadsheet