Issue 2, 2020

A global atmospheric chemistry model for the fate and transport of PFCAs and their precursors


Perfluorocarboxylic acids (PFCAs) are environmental contaminants that are highly persistent, and many are bio-accumulative and have been detected along with their atmospheric precursors far from emission sources. The overall importance of precursor emissions as an indirect source of PFCAs to the environment is uncertain. Previous studies have estimated the atmospheric source of PFCAs using models and degradation pathways of differing complexities, leading to quantitatively different results. We present results from simulations of atmospheric PFCA formation and fate using the chemical transport model GEOS-Chem. We simulate the most up-to-date chemistry available to our knowledge for the degradation of the precursors fluorotelomer alcohol (FTOH), fluorotelomer olefin (FTO), and fluorotelomer iodide (FTI), as well as the deposition and transport of the precursors, intermediates and end-products of the formation chemistry. We calculate yields of C3–C13 PFCAs formed from 4 : 2 to 12 : 2 fluorotelomer precursors and their deposition to the surface. We find that the ratio of long-chain to short-chain PFCAs increases strongly with distance from source regions. We compare our model results to remote deposition measurements and mid-latitude rainwater measurements. The model captures the observed relationship between rainwater abundance and PFCA chain length, as well as the average deposition rates at mid-latitude and Arctic sites, but underestimates the deposition of PFDoA, PFDA, and TFA at mid-latitudes and PFNA at the Devon Ice Cap. We provide estimates of cumulative PFCA deposition globally. We find that given the most recent emission inventory, the atmospheric source of PFCAs is 6–185 tonnes per year globally and 0.1–2.1 tonnes per year to the Arctic.

Graphical abstract: A global atmospheric chemistry model for the fate and transport of PFCAs and their precursors

Supplementary files

Article information

Article type
08 Jul 2019
14 Dec 2019
First published
24 Dec 2019
This article is Open Access
Creative Commons BY license

Environ. Sci.: Processes Impacts, 2020,22, 285-293

A global atmospheric chemistry model for the fate and transport of PFCAs and their precursors

C. P. Thackray, N. E. Selin and C. J. Young, Environ. Sci.: Processes Impacts, 2020, 22, 285 DOI: 10.1039/C9EM00326F

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity