ePO 106 – School indoor air as a relevant microenvironment for perfluoroalkyl carboxylic acid exposure
Ana Margarida Faria1, Georges Hatem1, David Dukes2, Carla Costa1, Amina Salamova2, João Paulo Teixeira1, Joana Madureira1
1 1 Environmental Health Department, National Institute of Health Dr. Ricardo Jorge, Porto, Portugal 2 EPIUnit – Instituto de Saúde Pública, Universidade do Porto, Porto, Portugal 3 Laboratório para a Investigação Integrativa e Translacional em Saúde Pública (ITR), Porto, Portugal, 2 Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Georgia, United States of America
Introduction: Perfluoroalkyl carboxylic acids (PFCAs) are persistent contaminants commonly detected indoors, with schools representing critical microenvironments given children’s prolonged exposure. This study assessed PFCAs in indoor and outdoor air from 8 Portuguese public primary schools. Methods: A total of 44 air samples (36 indoor classrooms and 8 outdoor locations) were collected using passive polyurethane foam samplers deployed for 28 days and analysed by liquid chromatography-triple quadrupole mass spectrometry. Concentrations were blank-corrected; medians were reported for compounds detected in ≥25% of both indoor and outdoor samples, while qualitative patterns were described for the rest. Results: Trifluoroacetic acid (TFA; 320 vs. 206 pg/m³ outdoors), perfluorohexanoic acid (PFHxA; 9 vs. 5 pg/m³), perfluorotetradecanoic acid (PFTeDA; 516 vs. 205 pg/m³), and perfluorooctadecanoic acid (PFODA; 1069 vs. 428 pg/m³) had higher concentrations indoors, while perfluorododecanoic acid (PFDoA; 848 vs. 1266 pg/m³) was higher outdoors. Perfluorodecanoic (PFDA) and perfluorohexanoic (PFHxA) acids showed higher concentrations indoors, while perfluorobutanoic acid (PFBA), perfluorohexadecanoic (PFHxDA), and perfluorotridecanoic acids (PFTrDA) had higher levels outdoors. Perfluorononanoic (PFNA), perfluorooctanoic (PFOA), perfluoropentanoic (PFPeA), and perfluoroundecanoic (PFUdA) acids were detected exclusively indoors, while perfluoroheptanoic acid (PFHpA) was undetected. Discussion: PFCAs detected more indoors were predominantly short-chain, which may reflect contributions from indoor sources (e.g., building materials, coatings, consumer products) and poor ventilation, whereas higher outdoor concentrations for selected long-chain PFCAs suggest atmospheric transport/deposition processes. Conclusion: Higher indoor concentrations were observed for most quantified PFCAs, highlighting the need to integrate ventilation and indoor air monitoring strategies in schools.