The regulations of the Montreal Protocol on Substances that Deplete the Ozone layer and its Amendments and Adjustments has led to the phase-out of chlorofluorocarbons (CFCs) and hydrofluorochlorocarbons (HCFCs) in the rigid foam blowing sector. As a consequence the production of new hydrofluorocarbons (HFCs) has recently begun. Their escape to the atmosphere has led to the first appearance and rapid growth of HFC-245fa (CHF2CH2CF3) and HFC-365mfc (CH3CF2CH2CF3) as observed at the Jungfraujoch SOGE station and now also at AGAGE stations. HFC-365mfc is currently produced in a single plant (France) and exclusively marketed in Europe. HFC-245fa is also produced in a single plant (Geismar, Louisiana) and predominantly marketed in North America.
The atmospheric background concentrations of both substances are very small and in the sub-ppt range. At Jungfraujoch, HFC-245fa has reached ~0.7 ppt at the end of 2005 while HFC-365mfc reached ~0.2 ppt at the end of 2004. HFC-365mfc emissions for central Europe were estimated at 400 - 500 t yr-1 for 2003 and 2004. For HFC-245fa, global emissions increased from 2100 - 2400 t in 2003 to 5100 - 5900 t in 2005. More measurements and improved modeling should help to further our understanding of the atmospheric budgets of these two compounds. Their current southern hemispheric emissions are negligible, suggesting that these new anthropogenic compounds may serve as interhemispheric transport tracers. Alternatively, because their only significant removal process from the atmosphere is OH, these compounds may help in assessing southern hemisphere OH concentrations.
For reprints and further information, please contact Martin Vollmer: firstname.lastname@example.org
European emissions of HFC-365mfc, a chlorine-free substitute for the foam blowing agents HCFC-141b and CFC-11. K. Stemmler et al. (2007), Environmental Science & Technology 41: 1145-1151.
First appearance and rapid growth of anthropogenic HFC-245fa (CHF2CH2CF3) in the atmosphere. M. K. Vollmer et al. (2006), Geophysical Research Letters 33: L20806.