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The Significance of PFAS in the Atmosphere

Elizabeth Denly, Tom Dunder, and Gary Hunt | November 13, 2023

Understand the Concerns and Prepare for Potential Issues

PFAS (per- and polyfluoroalkyl substances) represent a group of persistent chemicals that can cause adverse health effects in humans. These chemicals are found in many household products, such as non-stick cookware and food containers. When products containing PFAS are discarded, such as to a municipal solid waste landfill, into municipal wastewater treatment facilities, among other potential disposal scenarios, they can often re-enter the natural environment. PFAS may be emitted to the atmosphere in the form of a gas or associated with particulate matter. These chemicals are extremely persistent and do not break down easily.

As more scientific discoveries are made about PFAS chemicals, and more stringent regulations emerge, it is important for facility operators and other impacted entities to understand the associated risks and to plan for mitigation.

The Extent of PFAS Distribution in Air

Once PFAS enter the atmosphere, these compounds can remain airborne for long periods of time. As a result, PFAS compounds can be transported and deposited by wet and dry deposition onto soils and surface waters miles away from the original emission source. A study done by the North Carolina Department of Environmental Quality showed that PFAS (e.g., Gen-X) were detected in rainwater samples collected miles away from the Fayetteville Chemours Facility. This study shows how PFAS in air emissions from the Fayetteville Chemours Facility can remain in the atmosphere as an aerosol or adsorbed on particles, undergo atmospheric transport, and eventually be deposited remotely in rainwater. The rainwater in turn serves as a vehicle to facilitate movement of PFAS through the soil layer and potentially contaminating the underlying groundwater.

Similarly, a TRC-led study in Alachua, Florida showed that ambient air monitoring is an important tool for understanding PFAS in the atmosphere. This study used a modified high volume USEPA air sampling method to monitor PFAS concentrations in air. Results indicated that picogram per cubic meter (pg/m3) concentrations of several PFAS were detected. These data likely represent atmospheric background in the absence of any known emission source in the vicinity of the sampling site. Sampling performed by TRC at six other locations throughout the United States, as part of the same study, produced similar results confirming the ubiquity of PFAS in the atmosphere.

PFAS in Air is a Concern

As a result of their unique chemical and physical properties, PFAS deposited onto the ground and facilitated by rainwater can migrate through the soil into the underlying groundwater. This is a significant concern, as its ease of movement coupled with its persistence in the environment means that PFAS can enter drinking water aquifers, as has been seen in many states and municipalities in recent years.

Prepare for Potential Issues with PFAS Air Emissions

PFAS in air can impact PFAS levels in soil and water through deposition in areas far from the source. As more is learned about the pervasive nature of these chemicals and as the EPA and the states begin to develop more extensive PFAS regulations, being on top of the changes is becoming increasingly important for industry.

By understanding if your operation is using or emitting PFAS constituents, you will be able to develop effective plans to minimize, control and eliminate the source. It is important for your facility to work with a consultant who knows and understands the characteristics of PFAS compounds. Identifying PFAS requires more technical knowledge than typical environmental contaminants.

You can act now to identify and resolve potential current or historical liabilities that could result from direct or indirect sources of PFAS to the environment. Start by considering the following critical questions:

  • Do you or have you ever used aqueous film forming foam (AFFF) at your site?
  • Are you involved in any property transfers that may require testing for PFAS?
  • Are due diligence activities being performed on your site that require PFAS testing?
  • Are you prepared for the potential PFAS federal regulations (e.g., ASTM Phase I, CERCLA Hazardous substance designations, MCLs, TSCA, RCRA)?
  • Are there neighboring sites which may have PFAS issues?
  • How do you provide a defense that it is not your PFAS?
  • Are you or will you be required to monitor for PFAS as part of wastewater discharges?
  • Will you be required to monitor PFAS air emissions?
  • Do you have a plan to manage potential risk associated with PFAS? Have you determined if your site is a low or high-risk site?

TRC Can Help

TRC’s PFAS experts plan and manage the entire process to ensure our clients are prepared before money is spent on unnecessary treatment, containment, or disposal systems.

With staff located across the United States, we have a close watch on how developing legislation will affect our clients’ future. Prior to investing in stack testing and/or ambient air monitoring, it is important to understand your current PFAS risk/liability and develop plans to mitigate the impact. Let TRC assess and reduce potential liabilities from PFAS releases – our goal is to give you peace of mind during times of legal and regulatory uncertainty.

TRC offers many PFAS-related services, including stack testing and air monitoring, that can help you evaluate and solve your emission problems. For assistance in understanding PFAS, how it can impact your business and how TRC can help, please contact one of our trained professionals listed below.

Elizabeth Denly

Elizabeth Denly serves as TRC’s Vice President, PFAS Initiative Leader. She is also the Quality Assurance & Chemistry Director, responsible for the creation and implementation of the Quality Management Plan and standard operating procedures (SOPs) for field sampling and documentation protocols. Ms. Denly also leads Quality Coordinator networks, which are responsible for the development and communication of quality initiatives within the organization. She is a chemist with 29 years of consulting experience encompassing field and laboratory analyses and audits, QA/QC, data validation, and consulting for regulatory agencies.

Ms. Denly is a leader in ITRC’s PFAS and TPH Risk Work Groups and in TRC’s Center of Research & Expertise (CORE) Emerging Contaminants Team and received the ITRC’s Industry Member of the Year Award in 2017. She is currently focusing on PFAS, specifically the nomenclature, chemistry, sampling procedures, QA/QC, and laboratory analytical methodologies, and has a significant role in educating clients, attorneys, and regulators about PFAS.

As a senior QA specialist at TRC, Ms. Denly is responsible for providing QA/QC oversight in support of a variety of environmental investigations and remediation programs including risk-based soil cleanups, ambient air monitoring, and human health and ecological risk assessments. In this role, she has directed the preparation of QAPPs, coordination with the laboratory, selection of the appropriate analytical methodologies to achieve the desired remedial standards, oversight and performance of the data validation process, and determination of the usability of the data and achievement of data objectives. Ms. Denly has provided this oversight under different regulatory programs.
Read more on Ms. Denly’s bio page. Please contact her at

Tom Dunder, Ph.D.

Tom Dunder is Technical Director in the Air Management Services Division at TRC Companies in Raleigh, North Carolina where he performs and manages air pollutant testing programs. He has degrees in Chemistry from Columbia (A.B.), Rutgers (M.S.) and the University of North Carolina (Ph.D.). Tom has 29 years of experience in gaseous pollutant emissions measurements at a wide variety of industries (refineries, chemical plants, power plants, paper mills, etc.) with recent work in biomass/biogas processes and emerging pollutants like PFAS. Contact Tom at

Gary Hunt

Mr. Gary Hunt is a Vice President and Technical Director within TRC in their Lowell, MA office. Mr. Hunt is an internationally recognized expert on many aspects of Persistent Organic Pollutants (POPs) and other emerging contaminants in the global environment. He is a subject matter expert on PFAS in the atmosphere including measurement, distribution, occurrences, transport and fate. In recent years He has served as a member of the TRC PFAS CORE (Center of Research and Expertise) Team and a frequent lecturer at PFAS workshops held in Massachusetts, Connecticut and Rhode Island.
Mr. Hunt holds a B.S. in Chemistry from Villanova University (1974) and an M.S. in Environmental Sciences from Rutgers University (1977) and has 45 years of experience in environmental consulting. He has authored more than 125 journal manuscripts and symposia presentations on environmental topics, including POPs in the environment. Contact Mr. Hunt at

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