For decades, the story of PFAS contamination centered on water. Researchers are now paying closer attention to the air, both as a route of exposure and as a pathway that carries these chemicals far from where they were released.
Why PFAS Persist
Per- and polyfluoroalkyl substances are a class of thousands of human-made chemicals used in products such as food packaging, cleaning products, and personal care products. They can be found all over the world, and people can be exposed to them by breathing as well as through food and water.[1] Their persistence in the environment is why they're often called "forever chemicals."[2]
Long-Range Atmospheric Transport
PFAS have been found in remote places such as the Arctic, far from industrial activity. Research on Svalbard in the Norwegian Arctic describes how long-range atmospheric transport can happen in more than one way: volatile precursor compounds can travel through the atmosphere and oxidize along the way, and some PFAS move in the gas phase or attached to particles.[3]
The atmosphere isn't the only route. The same research identifies long-range ocean transport as another major pathway to the Arctic, and notes that the relative importance of atmospheric versus oceanic transport is still being worked out. Once deposited, PFAS in snow and ice can also be released again as it melts.[3]
Sea Spray Aerosol
PFAS can also move from ocean water into the air. In a laboratory sea spray chamber, researchers found perfluoroalkyl acids highly enriched in sea spray aerosols smaller than 1.6 µm, a size that facilitates long-range atmospheric transport, with concentrations up to roughly 62,000 times higher than in the water.[4] A later field study at two Norwegian coastal sites found evidence that sea spray aerosol is an important source of atmospheric PFAS to coastal areas.[5]
Dual-Phase Complexity: Why a Filter Alone Isn't Enough
PFAS in air don't exist in a single form. Some are carried in the gas phase and some are bound to particles,[3] which is why EPA's stationary source method for PFAS, OTM-45, addresses both semivolatile and particulate-bound PFAS.[6] A sampler that collects only a filter captures only part of the picture.
Dual-Phase Sampling with PUF
Tisch Environmental's polyurethane foam (PUF) samplers use a dual sampling module that collects particulate on a filter and vapor-phase compounds on PUF in a glass cartridge.[7][8]
- Filter: Collects airborne particulate in the upper chamber of the sampling module.[8]
- PUF Cartridge: Polyurethane foam, or PUF combined with XAD-2 resin, captures vapor-phase compounds in the lower chamber.[8]
Our PUF samplers have been used in several research studies to collect PFAS in ambient air, and EPA Method TO-13A has been found effective for collecting PFAS in ambient air.[1]
The Regulatory Picture
EPA's Other Test Method 45 (OTM-45) is a performance-based method for collecting and analyzing specific semivolatile and particulate-bound PFAS in air emissions from stationary sources, such as stacks.[6] For ambient air, there are no EPA-validated monitoring methods for PFAS,[9] which is why published research approaches, such as PUF sampling with TO-13A, carry so much weight in this field today.
Conclusion: Measuring the Full Picture
Looking at the air brings the full life cycle of PFAS into view. Whether a study focuses on emissions near a facility or on long-range transport, accurate dual-phase sampling is the foundation for understanding exposure and supporting public health decisions.
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