Determination of Legacy and Emerging Per- and Polyfluoroalkyl Substances (PFAS) in Indoor and Outdoor Air

Despite increasing awareness of health risks associated with exposure to per- and polyfluoroalkyl substances (PFAS), studies on analysis of these chemicals in air are limited. In this study, an extensive sampling of indoor and outdoor air (at a residential neighborhood) was performed to determine the occurrence, temporal variation, and gas/particle partitioning of PFAS. Among 58 PFAS analyzed in air (sum of gas and particulate phases), fluorotelomer alcohols (FTOHs) were found at the highest concentrations (1900 ± 2000 pg/m3). The concentrations of FTOHs and perfluorooctane sulfonamides (FOSA/E) were 4.9−5.9 times higher in indoor air than those in residential outdoor air (p < 0.05). Emerging PFAS such as hexafluoropropylene oxide dimer acid (HFPO-DA), chlorinated polyfluoroether sulfonate (Cl-PFESA), and ADONA were detected at average concentrations ranging from 0.10 to 4.4 pg/m3. We found significant temporal variations in PFAS concentrations, with concentrations higher in warmer than colder months. The majority of ionic PFAS (>50%) such as PFOS were detected in the particulate phase, whereas FTOHs partition predominantly to the vapor phase. This study establishes baseline indoor air concentrations of emerging PFAS and contributes to the understanding of gas−particle partitioning of PFAS.