EES Air Pollution Seminar: PFAS in the atmosphere with air quality models

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Emma D’Ambro, Ph.D., Chemist, US EPA

Abstract: Per- and polyfluoroalkyl substances (PFAS) are a large class of human-made compounds that have contaminated the environment both near and far from sources. To date, much of the scientific and regulatory focus has been on PFAS in drinking and surface waters, with a paucity of studies on air emissions, transport, and deposition, which is likely to contribute in part to water contamination. Air quality modeling techniques can be used to quantify air concentrations and deposition fluxes to help parse the role of exposure pathways such as direct inhalation and ingestion via contaminated water. We apply the Community Multiscale Air Quality model (CMAQ) version 5.3.2 to a case study in Eastern North Carolina to model the PFAS emissions and transport at fine scale (1 km) from the Chemours Inc. Fayetteville-Works. 26 PFAS with the largest emissions by mass are identified and added explicitly to CMAQ, along with an aggregate “other PFAS” species to represent the balance of the emissions. The Fayetteville-Works site is unique as it is the only fluorochemical manufacturer to our knowledge to provide a detailed accounting of quantified speciated emissions. We evaluate the CMAQ predictions for deposition against existing measurements and investigate the predicted air concentration and deposition throughout the domain, up to ~150 km from the facility.

Bio: Emma is a Research Chemist in the Office of Research and Development at the US EPA. She earned her PhD in Atmospheric Analytical Chemistry from the University of Washington in Seattle and joined the EPA in 2019. Her work focuses on adding per- and polyfluoroalkyl substances (PFAS), a suite of anthropogenically produced compounds, to CMAQ to investigate their atmospheric fate.