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Empirical analysis of vapor intrusion attenuation factors for sub-slab and soil vapor – an updated assessment for California sites

Vapor intrusion (VI) screening levels for sub-slab and soil vapor are often calculated using generic attenuation factors (AFs) based on findings of the 2012 USEPA empirical AF study. There are limitations and uncertainties associated with the USEPA database that are often not considered when applying the results of this study for risk-based decision making at chemical release sites.

A paper prepared for the Air & Waste Management Association’s Vapor Intrusion, Remediation, and Site Closure conference seeks to address the limitations based on data collected at VI sites in California. The paper, “Empirical Analysis of Vapor Intrusion Attenuation Factors for Sub-Slab and Soil Vapor – An Updated Assessment for California Sites,” written by a team of VI experts including Haley & Aldrich Principal Consultant Gina Plantz, presented data that is more representative of conditions in California.