Vapor Intrusion: Regulatory Updates and Practical Strategies for Assessing the Risk

Vapor intrusion (VI) continues to be an environmental hot topic in 2010.  USEPA is close to releasing an upgrade to its 2002 VI guidance with even stricter requirements, more states have released their own VI guidance, and an amendment to the ASTM VI standard released in March 2008 is coming.  The upshot of all these guidances is that more and more sites will require assessment of the VI pathway.       Assessment of the VI pathway is complicated due to inconsistent and contradictory state regulations, ultra-low screening levels, inexperience throughout the environmental community, and legal liability.  The keys to effective vapor intrusion assessments are choosing the proper approach through conceptual site modeling, determining correct screening levels, sampling & analyzing correctly and efficiently, and knowing when and how to use supplemental assessment tools.