Partitioning of Neutral Per- and Polyfluoroalkyl Substances (PFAS) Between Indoor Air and Various Reservoirs in North Carolina Homes: Results from the Indoor PFAS Assessment (IPA) Campaign

CLARA EICHLER, Naomi Chang, Jiaqi Zhou, Daniel Amparo, Elaine Cohen Hubal, Jason Surratt, Glenn Morrison, Barbara Turpin, UNC-Chapel Hill

     Abstract Number: 116
     Working Group: Indoor Aerosols

Abstract
Partitioning of per- and polyfluoroalkyl substances (PFAS) between indoor air and various reservoirs (e.g., settled dust, clothing) can prolong the residence time of PFAS indoors and contribute to PFAS exposure. During the UNC Indoor PFAS Assessment (IPA) Campaign, we collected samples of indoor gas phase, aerosols, settled dust, dust collected on heating and air conditioning (HAC) filters, pre-cleaned cotton cloth, and dryer lint in 10 homes in North Carolina over a period of nine months. We used gas chromatography-mass spectrometry (GC-MS, single quadrupole) for targeted analysis for nine neutral PFAS. Fluorotelomer alcohols (6:2, 8:2, and 10:2 FTOH) and perfluorooctane sulfonamidoethanols (MeFOSE and EtFOSE) were detected above method detection limits in all sample matrices, but concentration profiles differed among matrices. FTOHs are dominant in the gas phase and in settled dust, whereas FOSEs make up a larger fraction of the sum of measured neutral PFAS in the particle phase and in cloth. We used the data to derive partition coefficients for FTOHs and FOSEs. Shown as mean ±standard deviation, dust-air partition coefficients (log(K_dust), unitless) ranged from 7.3±0.7 for 8:2 FTOH to 8.8±0.5 for EtFOSE, while cloth-air partition coefficients (log(K_ca), unitless) ranged from 4.7±0.5 for 6:2 FTOH to 6.6±0.5 for EtFOSE, suggesting that per volume, PFAS partition to a larger extent to dust than to cloth. Partition coefficients are positively correlated with the octanol-air partition coefficient, log(K_oa). We further investigated removal rates of neutral PFAS from homes via dust vacuuming, air conditioning systems, and dryer lint. The findings of this study will inform PFAS transport and exposure models and contribute to more comprehensive policies for PFAS exposure mitigation.

Disclaimer: The views expressed in this presentation are those of the authors and do not necessarily represent the views or policies of the U.S. EPA.