Gas and Aerosol Phase PFAS Measured with Iodide HR-ToF-CIMS in Houston

Zachary Watson, Lee Tiszenkel, Vignesh Vasudevan Geetha, SHANHU LEE, The University of Alabama in Huntsville

     Abstract Number: 409
     Working Group: Chemicals of Emerging Concern in Indoor and Outdoor Aerosol: Sources, Vectors, Reactivity, and Impacts

Abstract
Per- and polyfluoroalkyl substances (PFAS) are a class of toxic synthetic compounds produced from industrial plants and manufacturing processes, and due their low chemical reactivities, they are referred to as “forever chemicals”. PFAS compounds have been detected typically using offline analytical techniques such as liquid chromatography mass spectrometry, but in-situ measurements of atmospheric PFAS are very limited. Here, we have measured PFAS compounds simultaneously in the gas and aerosol phase an iodide high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) attached to a Filter Inlet for Gases and AEROsols (FIGAERO) at the urban center of Houston, Texas in October, 2022. Our measurements identified several PFAS compounds including perfluorooctanoic acid (PFOA), hexafluoropropylene oxide dimer acid (HFPO-DA, GenX), perfluoropentanonic acid (PFPeA), and trifluoroacetic acid (TFA), both in the gas and aerosol phase. In this presentation, we will discuss the calibration, volatilities, gas-to-particle conversion, and potential associations of these PFAS compounds to other pollutant trace gases at the urban site. This is study represents one of the very few studies that measured PFAS at the urban residential areas at real time, thus will have important implications in understanding the effects of PFAS on urban air quality and public health.