Vapor Intrusion Investigations and Indoor Air Human Health Risk Assessments


Vapor Intrusion Investigations and Indoor Air Human Health Risk Assessments


USEPA, USACE, and Various Commercial Clients


  • Vapor Intrusion Investigations
  • Indoor Air Inhalation
  • Johnson and Ettinger Model
  • VOCs in Soil Vapor and Groundwater

Avatar has extensive experience in all facets of the vapor intrusion exposure pathway and health based assessments of indoor air.


The vapor intrusion (VI) pathway is an exposure pathway that is commonly encountered at various waste sites with volatile organic compound (VOC) contamination in the soil and/or groundwater. Avatar staff has extensive knowledge and experience in the evaluation of the VI exposure pathway. We have remained up-to-date on the evolving technologies and have implemented the technologies at a number of our sites.

Avatar scientists and engineers have designed and implemented sampling strategies for soil gas, subslab soil gas, and indoor air to support VI investigations for various government and private clients. We have comprehensively evaluated and interpreted the data collected as part of the investigations using multiple lines of evidence to determine the presence of the VI pathway and evaluate the potential exposure to building inhabitants.

Using empirical data, we have conducted a number of analyses ranging from risk-based screening evaluations using soil gas and indoor air data to baseline human health risk assessments of the indoor air at affected buildings. The risk analyses have been conducted in accordance with CERCLA guidance and guidance from various state agencies. In certain situations, empirical indoor air data directly related to the vapor intrusion pathway are not available. Avatar also has experience using the Johnson and Ettinger Model to predict indoor air concentrations from contamination observed in groundwater, soil gas, and soil.

The following list presents a few examples of vapor intrusion evaluations performed by Avatar:

  • EPA Region 1 at the Kellogg-Deering and McKin Superfund Sites
  • Sanford Dry Cleaners, JJ Seifert, and Smokey Mountain Smelters Superfund Sites (EPA Region 4)
  • Former Raritan Arsenal (USACE – New England and New York Districts)
  • LO-58 Nike Missile Site (USACE – New England District)
  • SL-10 Nike Missile Site (USACE – Louisville District)
  • Various commercial clients in Pennsylvania, South Carolina, Tennessee, and Virginia