text: The age of a water parcel can be estimated by the CFC partial pressure (pCFC) age or SF partial pressure (pSF) age. The pCFC age of a water sample is defined as:
  where [CFC] is the measured CFC concentration (pmol kg) and F is the solubility of CFC gas in seawater as a function of temperature and salinity. The CFC partial pressure is expressed in units of 10–12 atmospheres or parts-per-trillion (ppt). The solubility measurements of CFC-11 and CFC-12 have been previously measured by Warner and Weiss Additionally, the solubility measurement of CFC-113 was measured by Bu and Warner and SF by Wanninkhof et al. and Bullister et al.  Theses authors mentioned above have expressed the solubility (F) at a total pressure of 1 atm as:
  where F = solubility expressed in either mol l or mol kg atm,
  T = absolute temperature,
  S = salinity in parts per thousand (ppt),
  a, a, a, b, b, and b are constants to be determined from the least squares fit to the solubility measurements. This equation is derived from the integrated Van 't Hoff equation and the logarithmic Setchenow salinity dependence.
  It can be noted that the solubility of CFCs increase with decreasing temperature at approximately 1% per degree Celsius.
  Once the partial pressure of the CFC (or SF) is derived, it is then compared to the atmospheric time histories for CFC-11, CFC-12, or SF in which the pCFC directly corresponds to the year with the same.  The difference between the corresponding date and the collection date of the seawater sample is the average age for the water parcel. The age of a parcel of water can also be calculated using the ratio of two CFC partial pressures or the ratio of the SF partial pressure to a CFC partial pressure.