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Characterizing the air emissions, transport, and deposition of per- and polyfluoroalkyl substances from a fluoropolymer manufacturing facility
Citation:
D'Ambro, E., H. Pye, J. Bash, J. Boyer, C. Allen, C. Efstathiou, R. Gilliam, L. Reynolds, K. Talgo, AND B. Murphy. Characterizing the air emissions, transport, and deposition of per- and polyfluoroalkyl substances from a fluoropolymer manufacturing facility. International Journal of Environmental Science and Technology. Springer, Heidelburg, Germany, 55(2):862-870, (2021). https://doi.org/10.1021/acs.est.0c06580
Impact/Purpose:
We have shown that the new model, CMAQ-PFAS, when informed by estimated emissions from a fluoropolymer manufacturer, captures observed deposition fluxes of total GenX within a factor of 10 on average for the 5 measurement sites. This is consistent with predicted ambient air concentrations of 24.6 ng m-3 at the facility, which decreases with distance to ~0.1 ng m-3 35 km from the facility. We have further characterized the ambient air concentrations and domain-wide deposition of the total mixture of PFAS emitted by the facility and find that the annually averaged air concentrations reach a maximum of 8.5 µg m-3 near the facility and the majority of PFAS deposition (~95 %) is transported more than ~150 km away. Lastly, we find that the uncertainty related to acyl fluoride hydrolysis to carboxylic acid products in the atmosphere is relevant for predicting and constraining PFAS deposition within ~150 km from the facility. This work makes important steps towards both explicitly understanding the fate of PFAS air emissions from one manufacturing facility and building a methodology that quantifies regional-scale impacts of PFAS air emissions in general.
Description:
Per- and polyfluoroalkyl substances (PFASs) have been released into the environment for decades, yet contributions of air emissions to total human exposure, from inhalation and drinking water contamination via deposition, are poorly constrained. The atmospheric transport and fate of a PFAS mixture from a fluoropolymer manufacturing facility in North Carolina were investigated with the Community Multiscale Air Quality (CMAQ) model applied at high resolution (1 km) and extending ∼150 km from the facility. Twenty-six explicit PFAS compounds, including GenX, were added to CMAQ using current best estimates of air emissions and relevant physicochemical properties. The new model, CMAQ-PFAS, predicts that 5% by mass of total emitted PFAS and 2.5% of total GenX are deposited within ∼150 km of the facility, with the remainder transported out. Modeled air concentrations of total GenX and total PFAS around the facility can reach 24.6 and 8500 ng m–3 but decrease to ∼0.1 and ∼10 ng m–3 at 35 km downwind, respectively. We find that compounds with acid functionality have higher deposition due to enhanced water solubility and pH-driven partitioning to aqueous media. To our knowledge, this is the first modeling study of the fate of a comprehensive, chemically resolved suite of PFAS air emissions from a major manufacturing source.
URLs/Downloads:
DOI: Characterizing the air emissions, transport, and deposition of per- and polyfluoroalkyl substances from a fluoropolymer manufacturing facility
https://pubs.acs.org/doi/10.1021/acs.est.0c06580