Investigation of the production of TFA from two halocarbons, HFC-134a and HFO-1234yf and its fates using a global 3D chemical transport model

Rayne E T Holland, M. A. H. Khan, Isabel Driscoll, Rabi Chhantyal-Pun, Richard G. Derwent, Craig A. Taatjes, Andrew J Orr-Ewing, Carl J. Percival, Dudley E Shallcross*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

Trifluoroacetic acid (TFA), a highly soluble and stable organic acid, is photochemically produced by certain anthropogenically emitted halocarbons such as HFC-134a and HFO-1234yf. Both these halocarbons are used as refrigerants in the automobile industry and the high global warming potential of HFC-134a has promoted regulation of its use. Industries are transitioning to the use of HFO-1234yf as a more environmentally friendly alternative. We investigated the environmental effects of this change and found a thirty-three-fold increase in the global burden of TFA from an annual value of 65 tonnes formed from the 2015 emissions of HFC-134a, to a value of 2200 tonnes formed from an equivalent emission of HFO-1234yf. The percentage increase in surface TFA concentrations resulting from the switch from HFC-134a to HFO-1234yf remains substantial with an increase of up to 250-fold across Europe. The increase in emissions greater than the current emission scenario of HFO-1234yf is likely to result in significant TFA burden as the atmosphere is not able to disperse and deposit relevant oxidation products. The Criegee intermediate initiated loss process of TFA reduces the surface level atmospheric lifetime of TFA by up to 5 days (from 8 days to 3 days) in tropical forested regions.
Original languageEnglish
Number of pages9
JournalACS Earth and Space Chemistry
Volume(2021)
Early online date10 Mar 2021
DOIs
Publication statusE-pub ahead of print - 10 Mar 2021

Keywords

  • anthropogenic halocarbons
  • trifluoroacetic acid
  • atmospheric lifetime
  • global burden
  • Criegee intermediates

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