PFAS and Vapor Intrusion – ITRC Report

ITRC (Interstate Technology & Regulatory Council, US) published in January 2026 a fact sheet “Vapor-forming Per- and Polyfluoroalkyl Substances (PFAS)”. The fact sheet outlines the emerging understanding of vapor‑forming PFAS and their potential relevance to the vapor intrusion (VI) pathway. Current evidence indicates that certain neutral and ultrashort‑chain PFAS possess sufficient volatility to warrant consideration in VI assessments. Several studies have detected PFAS, including FTOHs (fluorotelomer alcohols) and some PFCAs (perfluorocarboxylic acids), in soil vapor, outdoor air, and indoor air, but more work demonstrating a complete subsurface‑ to‑indoor‑air VI pathway is warranted. Other challenges, according to the report, are the availability and variability of physical‑ chemical property data, such as vapor pressures and Henry’s law coefficients, and that more toxicological information for inhalation exposure to vapor‑phase PFAS is required.

Sampling, Analytical Methods, and Regulatory Considerations

The fact sheet concludes that sampling vapor‑forming PFAS can be a challenge, but the number of sampling and analytical protocols is increasing. Studies have primarily relied on sorbent‑based samplers (e.g. USEPA Method TO‑17) and other active or passive collectors to quantify PFAS in vapor phases. An observation is that current methods often do not distinguish between gas‑phase and particulate‑bound PFAS, adding complexity to the interpretation. Guideline values for PFAS in air vary widely among U.S. state agencies and international bodies, and to date no harmonized benchmarks exist. Existing air criteria generally target ionic, non-volatile PFAS such as PFOS and PFOA, which are less relevant to the VI pathway. However, recently the Hawai‘i Department of Health proposed interim VI‑related screening levels for a set of PFAS including 6:2 FTOH.

Eurofins Analytical Offer

Eurofins Pegasuslab, in collaboration with the Eurofins European PFAS Competence Centre, has developed a comprehensive concept for sampling PFAS in indoor air, sub‑slab air, and soil gas. The approach enables the simultaneous collection of both neutral PFAS such as FTOHs (6:2–12:2) and ionic PFAS including PFAS4 using a single sampler. Two XAD‑2‑based samplers are available. The OVS‑type sampler for indoor air incorporates a filter to capture particulate‑bound PFAS and a sorbent for gas phase constituents. Quantification at low limits of 0.2–1 ng/m³ for a 1 m³ sample is feasible. Eurofins provides both a targeted analytical package covering 16 compounds and a broader screening package of over 60 PFAS. Additional services include calibrated pump rental, soil gas sampling equipment, and PFAS analysis in dust samples to support comprehensive exposure assessments. See links for more information.

Links

ITRC fact sheet
Eurofins news
Eurofins/Sellén & Filipovic fire station study
PFAS in air (product sheet)