Superfund Research Program
Indoor Air Concentration Dynamics and Vapor Intrusion
Project Leader: Eric M. Suuberg
Grant Number: P42ES013660
Funding Period: 2009-2021
The Indoor Air Concentration Dynamics and Vapor Intrusion Project has developed an advanced mathematical modeling tool that describes the phenomenon of vapor intrusion (VI). VI involves evaporation from groundwater of volatile contaminants (e.g., chlorinated solvents, petroleum compounds) that then enter buildings built on the contaminated sites. Field investigation of VI is expensive, as well as alarming to those whose homes/workplaces are targeted. There is an incentive to correctly identify where site investigation is necessary, and to define a robust investigational strategy. Recent evidence of fluctuations in residential indoor air contaminant concentrations, combined with new toxicological data, have raised concerns in the regulatory community on how to be properly protective. The mathematical model developed in this program has given results indicating what leads to large fluctuations. The model has led the way to development of a new spreadsheet screening tool for both chlorinated and petroleum contaminated sites which can realistically predict significant indoor air impacts. The modeling also led to a conclusion that the US EPA guidance on VI is unnecessarily conservative in certain ways (Yao et al., 2018). The model is also being used to help guide design of systems that help mitigate exposures in vapor intrusion scenarios.
This Project has also studied removal of poly- and perfluoroalkyl substances (PFASs) from drinking water, using sorption to activate carbon. PFASs often co-occur in groundwater with the chlorinated solvents relevant to this Project. The factors defining useful carbons were systematically assessed, and results obtained showed that only certain ranges of porosity can be effective in removing PFAS from water.