The Occurrence of Emerging Per- and Polyfluoroalkyl substances (PFAS) in Indoor Dust from Different Microenvironments in South China.

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.