Atmospheric fate of poly- and perfluorinated alkyl substances (PFASs): I. Day–night patterns of air concentrations in summer in Zurich, Switzerland

Poly- and perfluorinated alkyl substances (PFASs) are anthropogenic pollutants ubiquitously found in the environment. Volatile PFASs are likely transported atmospherically over long ranges, but identification and quantification of emission sources is a challenging task. In this work, special meteorological conditions were utilized to quantify atmospheric emissions of Zurich City, Switzerland with a dual approach of modeling and field measurements. During high pressure systems in summer, a stable nocturnal boundary layer is formed in which pollutants are enriched. For volatile PFASs, a diel pattern of high concentrations in the night and low concentrations during the day was observed in Zurich, which is likely due to the atmospheric boundary layer dynamics. These results enable to model the emission source strength of Zurich City with a multimedia mass balance model in an accompanying paper. Cluster analyses suggested that perfluorocarboxylates (PFCAs) are a result of degradation of volatile precursors and direct emissions.

► Atmospheric PFAS concentrations in Zurich increase during the night.
► Diel concentration dynamics are likely due to stable nocturnal boundary layer.
► City is a source of PFASs to the atmosphere.
► 8:2 FTOH concentrations are high: up to 1200 pg/m3.
► PFAA concentrations are correlated with ozone, not particulate matter.