Quantification of per- and polyfluoroalkyl substances (PFAS) in air emissions: An interlaboratory comparison

To date, no widely adopted reference method exists for the quantification of PFAS in air emissions. The need is however clear and driven by the growing concern on PFAS health risks, lack of current air regulations, and the need for more effective mitigation strategies to avoid additional PFAS releases. A compendium method was developed in Belgium and turned into force since January 2024. This paper presents first empirical and comparative evidence on available monitoring methods for C4-18 PFAS in air emissions, by means of an interlaboratory comparison (ILC) evaluating method QA/QC, apparent spike recovery and measurement uncertainty of 50 individual PFAS compounds (C4-18) between 3 Belgian and 2 international laboratories. Besides confirming the validity of the recently published Belgian reference method and equivalence of the specified sampling train variants (OTM-45, OTM-45 variant and cooled probe), results provided insights in the retention potential of applied collection media (filter, XAD-2 and water), methodological issues and analytically challenging PFAS compounds. By evaluating various sampling train variants and techniques, this research aims to provide crucial insights into the effectiveness, accuracy, and reliability of these methods in detecting PFAS in air emissions. The findings contribute to cross-boundary standardisation of PFAS emission monitoring, which is currently a significant gap in both regulatory frameworks and scientific understanding.