Work

Atmospheric Removal of Trifluoroacetic Acid by Dry and Wet Deposition: A Multiyear Analysis in Toronto

Year: 2026

Type: article

Abstract: Trifluoroacetic acid (TFA) is a mobile and persistent compound that is widespread in the environment. While TFA forms in the atmosphere and deposition is its primary loss process, the relative contributions of wet and dry deposition pathways require better observational constraints. Here, we present a record of TFA in total, wet, and dry deposition in Toronto, Canada, between 2018 and 2024. Samples were collected using custom-built total and automated wet deposition samplers. All total (n=103) and wet (n=98) deposition samples contained TFA, with concentrations ranging from 0.07-4.55 µg L-1 and 0.09-3.19 µg L-1, respectively. Seasonal variation showed fluxes peaking in summer months, consistent with atmospheric oxidation of precursors as a major source. Fluxes in 2020 were statistically lower than other years by a factor of 2-5, coinciding with reduced anthropogenic activity during COVID-19 lockdowns. This provides compelling evidence that TFA sources in Toronto are mainly driven by short-lived precursors. The median dry deposition flux (104 µg m-2 a-1) accounted for 0-94 % (mean 45 %) of the total TFA deposition, higher and more variable than model estimates. These results provide the first field-based quantification of TFA in dry deposition, demonstrating that it is a significant and previously underrepresented removal pathway.

Source: Environmental Science & Technology Letters

DOI: 10.1021/acs.estlett.5c01100

Authors: Daniel Persaud, Shira Joudan, Trevor C. VandenBoer, Cora J. Young

Institution: York University

Language: English

Topic: Atmospheric chemistry and aerosols

Subfield: Atmospheric Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDG: Climate action

Open Access status: green

Funders: York University, Environment and Climate Change Canada, Natural Sciences and Engineering Research Council of Canada