Rapid growth of hydrofluorocarbon 134a and hydrochlorofluorocarbons 141b, 142b, and 22 from Advanced Global Atmospheric Gases Experiment (AGAGE) observations at Cape Grim, Tasmania, and Mace Head, Ireland

Abstract

An update of in situ Advanced Global Atmospheric Gases Experiment (AGAGE) hydrofluorocarbon (HFC)/hydrochlorofluorocarbon (HCFC) measurements made at Mace Head, Ireland, and Cape Grim, Tasmania, from 1998 to 2002 are reported. HCFC‐142b, HCFC‐141b, HCFC‐22 and HFC‐134a show continued rapid growth in the atmosphere at mean rates of 1.1, 1.6, 6.0, and 3.4 ppt/year, respectively. Emissions inferred from measurements are compared to recent estimates from consumption data. Minor updates to the industry estimates of emissions are reported together with a discussion of how to best determine OH concentrations from these trace gas measurements. In addition, AGAGE measurements and derived emissions are compared to those deduced from NOAA‐Climate Monitoring and Diagnostics Laboratory flask measurements (which are mostly made at different locations). European emission estimates obtained from Mace Head pollution events using the Nuclear Accident Model (NAME) dispersion model and the best fit algorithm (known as simulated annealing) are presented as 3‐year rolling average emissions over Europe for the period 1999–2001. Finally, the measurements of HCFC‐141b, HCFC‐142b, and HCFC‐22 discussed in this paper have been combined with the Atmospheric Lifetime Experiment (ALE)/Global Atmospheric Gases Experiment (GAGE)/AGAGE measurements of CFC‐11, CFC‐12, CFC‐113, CCl 4 , and CH 3 CCl 3 to produce the evolution of tropospheric chlorine loading.