Superfund Research Program
Indoor Air Concentration Dynamics and Vapor Intrusion
Project Leader: Eric M. Suuberg
Grant Number: P42ES013660
Funding Period: 2009-2021
People spend a majority of their lives indoors and this environment offers potential for human exposure to harmful chemicals, including those entering by vapor intrusion (VI) from the soil. Their concentrations may vary widely over time, and this project is examining the dynamics of such contaminant exposure, developing mathematical modeling tools to describe and predict it. Variability in indoor contaminant concentrations presents a major regulatory challenge. This project is providing those tasked with managing VI sites computational tools for understanding the variability in concentrations that may be expected, and allow them to make more realistic predictions of exposures than are possible now. Researchers earlier developed advanced engineering modeling tools to predict indoor concentrations in steady exposure scenarios, and are now modifying these models to explain variability. The chemical of special focus in this project is trichloroethylene (TCE) since recent environmental health literature has suggested certain short-term exposures to low concentrations of TCE might be of considerable significance. One of the newest tools in field investigation of VI sites is the Controlled Pressure Method (CPM) in which a structure of concern is subjected to significant under-pressurization and in a separate step, over-pressurization. While widely accepted as a way of defining the “worst case scenario” in VI, there have been no norms yet established for the extent of under-pressurization or its required duration in order to get meaningful results. The modeling work being performed is allowing these to be established.