THE AIR THAT WE BREATHE: NEUTRAL PFAS IN INDOOR AND OUTDOOR AIR

Abstract

Neutral, volatile perfluorinated alkyl substance (PFAS) precursors, such as fluorotelomer alcohols (FTOHs), perfluorooctane sulfonamides (FOSAs), and perfluorooctane sulfonamide ethanol (FOSEs) are industrial (by)products that are commonly present in indoor environments, and have been found in urban, industrial, and even rural locations. They have also been detected in remote regions, such as the Arctic, suggesting that these compounds are transported long distances in the. However, measuring volatile and neutral PFAS in air and water has proven to be challenging. Therefore, in order to accurately measure these compounds in different indoor and outdoor environments from urban, rural, industrial and remote regions, we proposed the use of apolar polyethylene (PE) sheets as a passive detection tool for air and water. The compounds of interest in this study included 6:2 FTOH, 8:2 FTOH, 10:2 FTOH. 8:2 FTAcr, 10:2 FTAcr, MeFOSA, MeFOSE, EtFOSA, and EtFOSE. Indoor sampling locations included classrooms, offices and laboratories from the University of Rhode Island, kindergarten classrooms and an outdoor clothing store in northern California, and classrooms, offices, laboratories and homes from the central valley of Jalisco, Mexico. Outdoor sampling of air and water included the North American Great Lakes, the Canadian Arctic, and Dhaka, Bangladesh. Studies were evaluated using two types of pre-cleaned PE passive samplers differentiated by thickness, and samples were analyzed by gas chromatography-mass spectrometry. These PE sheets were used to determine the partitioning coefficients (KPEa) and uptake of the volatile PFAS by these samplers. Results from the kinetic study showed that after 14 days of exposure equilibrium of the compounds into the PE sheets had been reached. Passive samplers were then paired with Radiello active samplers at an outdoor gear and clothing store to determine the KPEa of each compound. Partitioning between both PE sheets suggests that interactions of the passive samplers with the volatile PFAS are occurring by absorption. Gas-phase concentrations were paired with concurrently analyzed dust samples taken at the same locations in Californian kindergartens, and indoor air concentrations were linked to carpet and dust concentrations and the ventilation rates of the indoor environments. Results from all indoor studies indicated that volatile and neutral PFAS are ubiquitous in these environments, but that composition and concentration will vary depending on the contents of each location such as furniture, carpet, clothing, as well as ventilation rates. Volatile 6:2 FTOH was dominant in the U.S. indoor locations which was likely a reflection of the banning of longer chained