Cloth–Air Partitioning of Neutral Per- and Polyfluoroalkyl Substances (PFAS) in North Carolina Homes during the Indoor PFAS Assessment (IPA) Campaign
Partitioning of per- and polyfluoroalkyl substances (PFAS) to indoor materials, including clothing, may prolong the residence time of PFAS indoors and contribute to exposure. During the Indoor PFAS Assessment (IPA) Campaign, we measured concentrations of nine neutral PFAS in air and cotton cloth in 11 homes in North Carolina, USA, for up to 9 months. Fluorotelomer alcohols (i.e., 6:2 FTOH, 8:2 FTOH, and 10:2 FTOH) are the dominant target species in indoor air, with concentrations ranging from 1.8-49 ng m-³, 1.2-53 ng m-³, and 0.21-5.7 ng m-³, respectively, in total-air samples. In cloth, perfluorooctane sulfonamidoethanols (i.e., MeFOSE and EtFOSE) accumulated most significantly over time, reaching concentrations of up to 0.26 ng cm-² and 0.24 ng cm-², respectively. From paired measurements of neutral PFAS in air and suspended cloth, we derived cloth-air partition coefficients (Kca) for 6:2, 8:2, and 10:2 FTOH, ethylperfluorooctane sulfonamide (EtFOSA), MeFOSE, and EtFOSE. Mean log(Kca) values range from 4.7 to 6.6, and Kca values are positively correlated with the octanol-air partition coefficient (Koa). We also investigated the effect of the cloth storage method on PFAS accumulation, as well as the influence of home characteristics on air concentrations. Temperature had the overall greatest effect.