Measurement of Gas-Phase Perfluoroalkyl Carboxylic Acids (PFCAs) Using Nylon Passive Air Samplers

Abstract

Perfluoroalkyl carboxylic acids (PFCAs) are persistent anthropogenic compounds widely detected in environmental media. Few studies have measured ultrashort-chain PFCAs in air, despite their higher abundance compared to longer chains. Nylon passive air samplers (PAS) provide a cost-effective, low-labour technique to measure ultrashort- and short-chain gas-phase PFCAs. Method quality control and quality assurance parameters were optimized, including the calibration of perfluorobutanoic acid (PFBA), thereby improving confidence in reported mixing ratios. In a novel intercomparison with sorbent-impregnated polyurethane-foam (SIP) PAS at a wastewater treatment plant, good agreement between measurements was observed, with ultrashort-chain PFCAs dominating emissions. Nylon PAS were deployed in multiple Toronto locations, revealing Pearson International Airport to be a potential point source of perfluoropropanoic acid (PFPrA). Large-scale regional sampling along the St. Lawrence River, Quebec showed positive correlations between PFBA concentration and population size. These measurements have provided valuable insights into the sources and spatial distribution of PFCAs.