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Per- and polyfluoroalkyl substances (PFAS) have been applied in numerous industrial and consumer products, the majority of which flow into waste management infrastructures (WMIs) at the end of their life cycles, but little is known about atmospheric releases of PFAS from these facilities. In this study, we addressed this key issue by investigating 49 PFAS, including 23 ionic and 26 neutral and precursor PFAS, in the potential sources (n = 4; within or adjacent to WMIs) and reference sites (n = 2; coastal and natural reserve sites) in urban and rural areas of Hong Kong, China. Duplicate samples of air and size-segregated particulate matter were collected for 48 h continuously using a 11-stage Micro-Orifice Uniform Deposit Impactor (MOUDI). In general, fluorotelomer alcohols (FTOHs) and perfluoroalkane sulfonamides were the predominant PFAS classes found across sampling sites. We also demonstrated the release of several less frequently observed semivolatile intermediate products (e.g., secondary FTOHs) during waste treatment. Except for perfluorooctane sulfonate, the size-segregated distributions of particulate PFAS exhibited heterogeneity across sampling sites, particularly in the WMIs, implying combined effects of sorption affinity and emission sources. A preliminary daily air emission estimation revealed that landfill was a relatively important source of PFAS relative to the wastewater treatment plant. A simplified International Commission on Radiological Protection model was used to estimate lung depositional fluxes, and the results showed that inhaled particulate PFAS were mainly deposited in the head airway while fine and ultrafine particles carried PFAS deeper into the lung alveoli. The cumulative daily inhalation dose of gaseous and particulate PFAS ranged from 81.9 to 265 pg/kg/d. In-depth research is required to understand the health effect of airborne PFAS on workers at WMIs., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Bioaccessibility of particle-bound hydrophobic organic contaminants and related particle size effects are significant for assessing the potential human health risk via inhalation exposure, but have not been clearly evaluated. To fill this knowledge gap, the present study developed an in vitro method to estimate the inhalation bioaccessibility of particulate polycyclic aromatic hydrocarbons (PAHs) using simulated human lung fluids, i.e., a modified Gamble's solution (MGS) and artificial lysosomal fluid (ALF) with Tenax as the absorption media. Assay parameters, namely incubation time (10 d) and influence of filter use, were optimized for establishing the in vitro method. The results showed that the bioaccessibility of PAHs increased with increasing particle size, but other factors, such as total organic carbon and chemical hydrophobicity, also played a large role in the fate of these compounds. The results from this portion of the present study were then used to evaluate human health risk, which showed that the risk of these particle-bound PAHs by incorporating size-dependent PAHs bioaccessibility and deposition efficiency in the human respiratory tract into inhalation exposure risk calculations was reduced by >90% when compared to using total concentration. This suggested that the inhalation bioaccessibility and deposition efficiency of hydrophobic organic chemicals should be included in human health risk assessment., (Copyright © 2018 Elsevier Ltd. All rights reserved.)