This study investigated the particle size distribution and atmospheric transport potential of perfluoroalkyl carboxylic acids (PFCAs) and certain perfluoroalkyl ether carboxylic acids (PFECAs) emitted from a mega fluoropolymer industrial park (FIP) in China. Ambient aerosols sampled in a residential area near the FIP were separated by a cascade impactor into five size fractions (<0.15 to 12.15 μm). Homologues of PFCAs (C5-C11) and five PFECAs were frequently detected in the samples (detection frequencies 40-100%), albeit not in all size fractions. Perfluorooctanoic acid (PFOA) exhibited the highest concentrations (6.5 to 2900 pg m-3). A noticeable mass mode in the >1 μm size range was observed for PFCAs and PFECAs in the samples that were directly influenced by wind from the direction of the FIP. Based on the PFOA concentrations in the aerosol samples, the emission rate of PFOA to air from the FIP was estimated to be 0.4-1.3 t year-1. Modeling results demonstrated that around 67% of the PFOA air emission was transported in the atmosphere above 1500 m in a 7 day continuous emission scenario, implying that the PFOA on <12.15 μm particles undergoes long-range atmospheric transport after being emitted from the FIP.

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals of environmental and human health concern due to their persistence, potential toxicities, and potential to bioaccumulate. Fluoropolymers, a subset of polymeric PFAS, consist of a carbon backbone that is fully or partially fluorinated. This structure confers unique properties such as chemical and thermal resistance, as well as hydrophobicity and lipophobicity and has led to diverse industrial and consumer applications of fluoropolymers. As such, these materials are positioned as a significant component of the global fluorochemical industry and economy.

However, fluoropolymer production has raised concerns due to the use, formation, and emission of various non-polymeric PFAS. In response, industry has sought to mitigate its impacts by introducing alternative PFAS, implementing emission abatement technologies, and modifying production processes.

This thesis aimed to determine and characterize PFAS emissions from fluoropolymer production plants (FPPs) in Europe and China by gaining a holistic understanding of production processes to identify sources and emission pathways. Emissions were captured through emission data collection (Paper I) and environmental sampling near FPPs (Papers II-IV) and further characterized through an emission inventory (Paper I), targeted analyses, suspect screening (Papers II-IV), and atmospheric dispersion modelling (Papers II and IV). Differences in management of PFAS emissions by FPPs between China and Europe were investigated by comparing measured atmospheric concentrations and assessing the implications for human exposure.

Results indicated that despite recent emission reduction efforts in the UK and the Netherlands, FPPs remain point sources of various PFAS, including introduced alternatives (Papers I-III). Perfluorooctanoic acid (PFOA), which was listed in the Stockholm Convention on Persistent Organic Pollutants in 2019, was still in use and emitted in large quantities during the sampling period in China in 2019 (Paper IV). Other identified emissions included monomeric PFAS, by-products from monomer production and polymerization, and PFAS used in fluoropolymer processing (Paper I). Furthermore, due to the persistence of PFAS, historical emissions have turned some production sites into contamination hotspots (Paper III).

Atmospheric dispersion modelling (Papers II and IV) showed that part of the atmospheric PFAS emissions could be subject to long-range atmospheric transport and contribute to PFAS loads in remote locations. Thus, PFAS emissions by FPPs not only influenced the local environment, but possibly had global impacts. Measured median concentrations of atmospheric PFAS (Papers II-IV) exceeded guidance values for exposure through inhalation 30 km from the FPP in China. Before the implementation of emission abatement systems, a similar situation could have existed in the Netherlands and the UK, due to emissions of PFOA and its replacements.

Overall, this thesis underscored the need for a broader scope in future research and regulatory efforts, extending beyond specific well-known PFAS to encompass other PFAS emissions by FPPs. Additionally, addressing geographical disparities in PFAS management is crucial for effective global solutions.

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 r = 0.83, p ≤ 0.05, Wilmott’s d = 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.

Multiple target and suspect per- and polyfluoroalkyl substances (PFAS), including the replacement fluorinated processing aid perfluoro(2-ethoxy-2-fluoroethoxy)-acetic acid ("EEA"), were measured in both air and surface water in the vicinity of a fluoropolymer production plant (FPP) in Thornton-Cleveleys (United Kingdom) during sampling campaigns in 2021 and 2023, respectively. Targeted and suspect screening methods were conducted using ultrahigh-performance liquid chromatography (UHPLC) coupled with Q-Exactive HF Orbitrap high-resolution mass spectrometry (HRMS). Summed PFAS levels in water nearby the plant ranged from 30 to 22,542 ng/L and were dominated by perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl ether carboxylic acids (PFECAs), most notably perfluorooctanoic acid (PFOA; up to 20,624 ng/L), EEA (up to 1744 ng/L), H-PFOA (up to 1027 ng/L), and perfluorohexanoic acid (PFHxA; up to 650 ng/L). Additionally, various homologous series of PFAS suspects, such as hydrogen-substituted PFCAs (H-PFCAs), chlorine-substituted PFCAs (Cl-PFCAs), and monoether perfluoroether alkyl carboxylic acids (ME-PFECAs) were identified, some for the first time in Europe. In air, PFOA was detected in all but one sample collected 20 km from the plant at concentrations ranging from 0.51 to 2.50 pg/m3. The three air samples that showed detectable EEA concentrations also displayed evidence of long-chain targets and suspects and were associated with high wind speeds from a southwesterly direction. Overall, this study shows that this site continues to be a source of a complex mixture of legacy and scarcely monitored PFAS that occur in multiple environmental media. This highlights the importance of further research that assesses the toxicity of these substances and the resulting impacts on humans and wildlife.