When Vapor Intrusion Gets Complicated: Design, Testing, and What Really Matters

In this episode of The Indoor Environments Project, host Diane Swecker is joined by Rachel Peterson, P.G., Environmental Department Manager at AGW, and Tony McDonald, CEO of A-Z Solutions, for a deep dive into vapor intrusion in practice.

While vapor intrusion is often discussed alongside radon mitigation, this conversation explores where the similarities end — and where complexity begins.

Together, they unpack how vapor intrusion projects are identified, designed, and executed in real-world settings, including:

•  What types of sites present vapor intrusion risk and how those risks are evaluated 
•  The role of the conceptual site model in shaping mitigation decisions 
•  Key differences between radon mitigation systems and vapor intrusion systems
•  Why verification testing can be significantly more complex, especially when VOCs from building materials influence results 
•  How pilot testing and pressure field data inform system design 
•  Why successful projects depend on a multidisciplinary team, including consultants, regulators, and mitigation professionals 

The discussion also highlights common challenges in the field, including misinterpretation of data, overreach in project scope, and the importance of understanding the limits of your expertise.

Whether you’re a radon professional expanding into vapor intrusion, an environmental consultant, or involved in building design and redevelopment, this episode provides valuable insight into the realities of vapor intrusion work.

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