HFPO-DA and Other PFAS in Air Downwind of a Fluoropolymer Production Plant in the Netherlands: Measurements and Modeling

Emissions of historical fluorinated processing aids used in fluoropolymer production are known to have contributed significantly to environmental levels of persistent perfluoroalkyl acids (PFAAs). Less is known about emissions of contemporary processing aids and the efficacy of technology used to contain them. To address this, we investigated the occurrence of hexafluoropropylene oxide dimer acid (HFPO-DA) and other per- and polyfluoroalkyl substances (PFAS) in airborne PM10 near a fluoropolymer production plant in the Netherlands. The 20-week high-volume air sampling campaign coincided with installation of emission abatement systems. HFPO-DA levels ranged from below detection limits to 98.66 pg m^-3 when the wind came from the plant, and decreased to a maximum of 12.21 pg m^-3 postabatement. Lagrangian dispersion modeling using FLEXPART revealed good concordance between measured and modeled HFPO-DA concentrations (Pearson's <i>r</i> = 0.83, <i>p</i> ≤ 0.05, Wilmott's <i>d</i> = 0.71, mean absolute error = 3.66 pg m^-3), providing further evidence that the plant is a point source. Modeling also suggested that HFPO-DA could undergo long-range atmospheric transport with detectable HFPO-DA air concentrations predicted up to several thousand kilometers away. Besides HFPO-DA, the fluorinated processing aid 6:2 fluorotelomer sulfonate and the suspected polymerization byproducts, hydrogen-substituted perfluoroalkyl carboxylic acids, were also observed, highlighting the complex mixture of PFAS emitted by the plant.