Environmental context. Polyfluorinated compounds are an emerging group of organic pollutants that are globally distributed in urban and natural environments. Reliable air monitoring methods are crucial to our understanding of how these pollutants are released to, and transported in, the atmosphere. This intercomparison study, involving laboratories that investigate polyfluorinated compounds in air, uncovers inconsistencies in the reported data, and highlights necessary analytical improvements for future research projects.

Abstract. Fluorotelomer alcohols, perfluorinated sulfonamides or sulfonamido ethanols are volatile precursors of persistent perfluorinated acids. Published air-sampling strategies and analytical methods to determine these compounds differ. To assess performance on the determination of airborne polyfluorinated compounds, an intercomparison comprising four international research groups was established. Instrumental and analytical comparability between laboratories varied depending on the compound class. Variability in different sampling strategies was assessed for active (high-volume) v. passive samplers consisting of either semipermeable membrane devices or sorbent-impregnated polyurethane foam disks. Results from passive samplers were typically within an order of magnitude of air concentrations from averaged continuous high-volume samples. Smallest deviations (passive v. active) were observed for sorbent-impregnated polyurethane foam disk samplers with best agreement for fluorotelomer alcohols. This study reveals that it is important to be aware of several types of uncertainty or error for the determination of airborne polyfluorinated compounds and report data in this context or to take steps to minimise their impact.