Partitioning of Neutral PFAS in Homes and Release to the Outdoor Environment: Results from the IPA Campaign

The distribution and fate of per- and polyfluoroalkyl substances (PFAS) in homes are not well understood. To address this, we measured nine neutral PFAS in dust, airborne particles, dryer lint, and on heating and air conditioning (HAC) filters in 11 homes in North Carolina as part of the Indoor PFAS Assessment (IPA) Campaign and compared them with concurrently collected gas and cloth measurements. Fluorotelomer alcohols (FTOHs) contributed most (≥75%) to total (∑) measured neutral PFAS concentrations in dust, HAC filter, and dryer lint samples, with mean ∑(FTOH) concentrations of 207 ng/g, 549 ng/g, and 84 ng/g, respectively. In particles, perfluorooctane sulfonamidoethanols (FOSEs) dominated, with a mean ∑(FOSE) concentration of 0.28 ng/m³ or 75,467 ng/g. For FTOHs and FOSEs, resulting mean dust-air, HAC filter-air, dryer lint-air and particle-air partition coefficients in units of log(m³/μg) ranged (across species) from -5.1 to -3.6, -4.9 to -3.5, -5.4 to -4.1, and -3.2 to -0.78, respectively. We estimate that cloth, gas phase, and HAC filters are the largest reservoirs for FTOHs, while cloth, HAC filters, and dust are the largest reservoirs for FOSEs. Release rates of neutral PFAS from homes to the outdoor environment are reported.