Aug 2026· Environmental Research· pp.
125533
· 0 citations· 67 references
Medicine
TL;DR
Although PFAA precursors predominated in indoor air, PFAAs accounted for the largest share of estimated inhalation exposure under the high-exposure scenario, highlighting the importance of considering both PFAA precursors and PFAS in comprehensive exposure assessments.
Abstract
Background
Per- and polyfluoroalkyl substances (PFAS) are persistent environmental pollutants increasingly detected in indoor environments, yet information on PFAS in school settings remains scarce.
Objective
We characterized PFAS levels in primary school indoor air and estimated inhalation exposure among children and school staff.
Methods
We collected 36 indoor and 8 outdoor air samples from 8 primary schools in Porto (the second-largest city in Portugal) and analyzed them for 64 PFAS, including perfluoroalkyl acids (PFAAs) and PFAA precursors.
Results
PFAA precursors predominated over terminal PFAAs, accounting for 66.5% and 64.6% of total PFAS in indoor and outdoor air, respectively. Among PFAAs, perfluoroalkyl carboxylic acids (PFCAs) were the dominant class in both indoor and outdoor air (median: 3822.3 and 495.1 pg/m3, respectively), whereas polyfluoroalkyl phosphate esters (PAPs; median: 2811.6 and 732.0 pg/m3) and fluorotelomer alcohols (FTOHs; median: 1436.6 and 313.5 pg/m3) were the predominant PFAA precursors. Trifluoroacetic acid (TFA), perfluorooctane sulfonate (PFOS), nonafluoro-3,6-dioxaheptanoic acid (NFDHA), di-sulfonamido polyfluoroalkyl phosphate (diSAmPAP), and 8:2 fluorotelomer alcohol (8:2 FTOH) were the major individual PFAS detected indoors. All PFAS classes showed indoor enrichment relative to outdoor air. Children had higher body-weight-normalized inhalation exposure than adults. Under the low-exposure scenario, FTOHs contributed most to total EDI, whereas PFCAs predominated under the high-exposure scenario.
Conclusion
Primary schools constitute important indoor microenvironments for PFAS exposure. Although PFAA precursors predominated in indoor air, PFAAs accounted for the largest share of estimated inhalation exposure under the high-exposure scenario, highlighting the importance of considering both PFAA precursors and PFAS in comprehensive exposure assessments.
Per- and polyfluoroalkyl substances (PFAS) have attracted attention because of their persistence and widespread occurrence in indoor environments. This study investigated the occurrence, distribution, and exposure risks of PFAS in indoor dust from different university environments. The associations between indoor dust and hair PFAS concentrations were explored. The average ∑PFAS concentration in dust from unrenovated dormitories (Type Ⅱ, 126.61 ng/g) exceeded that in renovated dormitories (Types Ⅰ and Ⅲ, 63.81 and 54.65 ng/g, respectively). Hair samples from students across all three dormitory types showed PFAS accumulation, with perfluorooctanoic acid (PFOA) as the dominant compound (75.46%, average: 1.15 ng/g). PFAS burdens in hair varied markedly across dormitory types, with average ∑PFAS concentrations of 4.67 ng/g for Type Ⅰ (renovated), 1.00 ng/g for Type Ⅲ (renovated), and 0.49 ng/g for Type Ⅱ (unrenovated). Significant positive correlations between ∑PFAS concentrations in dust and hair (r = 0.77, p < 0.01) suggest that indoor dust may represent a potential contributor to PFAS accumulation in human hair, highlighting the potential of hair as a non-invasive biomonitoring matrix for long-term PFAS exposure. Although the estimated exposure risks were relatively low, the widespread occurrence of PFAS highlights indoor environments as a potential source of chronic human exposure.
Yuan-Hang Zhang, Shunzhe Wei, Wanru Yang et al.· Journal of Hazardous Materia...· 0 citations
Despite extensive research on the environmental contamination of per- and polyfluoroalkyl substances (PFAS), their occurrence across diverse indoor microenvironments remains insufficiently characterized. In this study, we analyzed a broad spectrum of PFAS in dust samples collected from residential settings (n = 14) and six types of public environments in South China between July and September 2022, using ultra-performance liquid chromatography coupled with triple-quadrupole mass spectrometry (UPLC-MS/MS). Of the 35 target compounds, 19 PFAS were detected with detection frequencies exceeding 50%. Ultrashort-chain perfluoroalkyl acids (PFAAs) and their precursors emerged as the dominant species, with concentrations substantially higher than those of legacy compounds such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). PFAS concentrations varied by microenvironment, with offices exhibiting the highest levels (median 516 ng/g), likely attributable to the widespread use of PFAS-containing materials and confined space. Estimated exposure via dust ingestion revealed that toddlers experienced the highest intake (0.692 ng/kg/day) among all age groups in household environments, due to greater dust ingestion rates. Our study highlights the widespread occurrence of emerging PFAS, including ultrashort- and short-chain PFAAs and PFAA precursors, in indoor environments in South China and emphasizes the importance of ongoing surveillance and regulatory measures for these substances.
Yu-Ge Liang, Xiaoyuan Guo, Chenglin Liu et al.· Environmental Pollution· 0 citations
The results of the total carcinogenic risk for children aged 7–12 years in all schools caused by the presence of PAHs compounds in outdoor environments was acceptable and in some indoor environments, the values at certain schools exceeded the standard threshold of 10− 6-10− 4, indicating potential health risks.
Mohamad Firdaus Ismail, M. F. Fadzil, Nur Atifah binti Mohd Naim et al.· Asian Journal of Atmospheric...· 0 citations
The people of the Faroe Islands are uniquely exposed to per- and polyfluoroalkyl substances (PFASs); despite no local production of these compounds or manufacturing of consumer products, residents exhibit elevated serum concentrations of PFASs. Consumption of pilot whales, a traditional part of the Faroese diet, contributes to exposure but does not fully account for observed trends in serum, suggesting the importance of additional exposure pathways. This research assessed the significance of indoor exposure pathways through measuring air and dust concentrations of a broad scope of PFAS nonvolatile precursors, volatile neutral precursors, and legacy ionic PFASs, and determining the estimated daily intake (EDI) for 15-year-old children. Across the 40 homes, the EDI for children from indoor exposure was 0.001, 0.012, and 0.129 ng/kg bw for low, intermediate, and high exposure scenarios, respectively. Indirect exposure to perfluoroalkyl carboxylic acids from air contributed the most to the EDI, followed by indirect exposure to perfluorooctanesulfonic acid in dust in the high exposure scenario. Indoor exposure equated to approximately 0.2% (low), 2% (intermediate), and 20% (high) of the European Food Safety Authority (EFSA) tolerable weekly intake, while the average consumption of pilot whale contributed about 60%. This study highlights the importance of understanding indoor exposure as a potentially significant contributor to total exposure to PFAS, especially with the declining consumption of pilot whales in the Faroese population.
Melissa Woodward, Jitka Bečanová, S. Vojta et al.· Environmental Science and Te...· 0 citations
The analysis revealed mostly long-chain legacy PFAS with possibly different exposure risks for secluded interior communities compared to urban-coastal populations, indicating a need for contaminant source assessments.
Jenna K. Honan, F. A. Wahid, Anisma R. Gokoel et al.· Journal of Exposure Science...· 0 citations
The findings suggest that exposure to low levels of some alternative and precursor PFAS may be widespread in Canada and reinforce the role of pregnancy and breastfeeding as excretion pathways for legacy PFAS and support previous investigations demonstrating that exposure to some PFAS may be lower amongst financially disadvantaged populations.
M. Borghese, Rebecca Lelievre, Sara Packull-McCormick et al.· Environmental Health· 0 citations
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