Spatial and seasonal distribution, sources, and health risks of PM_2.5 loaded per- and polyfluoroalkyl substances...

Per- and polyfluoroalkyl substances (PFASs), a class of ubiquitous and emerging environmental pollutants, have garnered considerable attention due to the scarcity of knowledge regarding their atmospheric sources and the associated human health risks from aerosol exposure. This study investigated the spatial-temporal distribution and potential sources of PFASs in Nanjing city of eastern China by collecting 66 PM_2.5 samples from industrial, urban, and rural areas between July 2022 and August 2023. Employing ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), 21 distinct PFASs were detected with concentrations ranging from 9.62 to 136 pg·m^-3, predominantly higher in urban areas. Airborne PFASs concentrations exhibited seasonal fluctuations, with the highest levels observed in autumn, followed by spring, summer and winter. Diagnostic ratio and positive matrix factorization (PMF) for source analyses revealed the significant influence of long-range transport, the textile and paper packaging industry, and the decomposition of fluorochemical precursors were identified as the main contributors, accounting for 18.2 %, 15.8 %, and 16.1 % respectively. Population exposure was evaluated through deposition and dermal penetration modeling, with inhalation intake estimated at 2.05 pg·kg^-1·d^-1 and dermal contact intake at 1.01 pg·kg^-1·d^-1. Among the 21 assessed PFASs, perfluoro-n-hexanoic acid (PFHxA) was identified posing the most significant risk regarding respiratory effects, skin sensitization, and carcinogenic potential. This research provides critical insights into the spatial and seasonal distribution of atmospheric PFASs and the assessment of combined human exposure risks in rapidly developing areas.