Current knowledge about per- and polyfluoroalkyl substances (PFAS) in the atmosphere: Fate, analytical methods and research priorities

Per- and polyfluoroalkyl substances (PFAS) are increasingly recognised as ubiquitous atmospheric contaminants. The atmosphere, in turn, is an important compartment for distributing these compounds throughout the environment, allowing human exposure through inhalation and/or dermal contact. This study provides a comprehensive overview of the current knowledge on PFAS, covering: (i) a compilation of information on emission sources – primary sources (production, manufacturing, use of AFFF, waste handling, marine spraying) and secondary sources (oxidative degradation of neutral PFAS); (ii) proposed classifications of the volatility of these substances based on vapor pressure by the U.S. Environmental Protection ECHA – European Chemicals Agency (2025); (iii) atmospheric processes that govern gas-particle partitioning, long-range transport, and deposition; (iv) an assessment of current and emerging sampling and analytical techniques, including OTM 45/50 methods; and (v) the identification of priority knowledge gaps. Among the main existing gaps, the validation of improved monitoring strategies and inhalation toxicity studies for neutral precursors could significantly contribute to a robust risk assessment and support regulatory efforts within the evolving global agenda for the phase-out of PFAS.