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Underground Storage Tanks (USTs)

Petroleum Vapor Intrusion

Introduction

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Overview of Petroleum Vapor Intrusion (PVI)

Vapor intrusion occurs when vapor-phase contaminants migrate from subsurface sources into buildings. One type of vapor intrusion is PVI, in which vapors from petroleum hydrocarbons such as gasoline, diesel, or jet fuel enter a building. The intrusion of contaminant vapors into indoor spaces is of concern due to potential threats to safety (e.g., explosive concentrations of petroleum vapors or methane) and possible adverse health effects from inhalation exposure to toxic chemicals.

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PVI Guidance

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PVI Database

In support of its general guidance development effort for the petroleum vapor intrusion exposure pathway, EPA compiled an empirical database of measurements of subsurface media (soil gas, soil, and groundwater) and supporting data from 74 sites, including 69 sites in 10 states, 4 sites in Canada, and 1 site in Australia.

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PVIScreen

EPA's screening tool for developing a modeling-based line of evidence to assess the potential for petroleum vapor intrusion (PVI) impacts on buildings can help regulators make informed decisions on when sites can be screened out from further investigation.

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PVI Technical Supporting Documents

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Additional Vapor Intrusion Resources

  • Vapor Intrusion website
    This website provides basic information regarding non-petroleum vapor intrusion (e.g., vapor intrusion from chlorinated solvents) including technical and policy documents to support environmental investigations, and highlights of recent and upcoming activities related to vapor intrusion.
  • Vapor Intrusion Issue Area on EPA’s CLU-IN
    CLU-IN issue areas bundle available information associated with specific topics. These issue areas are updated with information from federal cleanup programs, state sources, universities, nonprofit organizations, peer-reviewed publications, and public-private partnerships.

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Generation, Transport, and Fate of Vapors in the Subsurface

The resources below provide information on the generation, transport, and fate of petroleum vapors in the subsurface.

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Sampling Methods and Analyses and Site Characterization

The resources below provide information about sampling methods and analyses as well as site characterization. 

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Indoor Air Sampling Methods and Analysis

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Soil Gas Sample Collection and Sample Analysis Methods

The resources below provide information about soil gas sample collection and sample analysis methods, focusing on sites where PVI may be a concern.

  • Hers, Ian, Loretta Li, and S. Hannam. Evaluation of Soil Gas Sampling and Analysis Techniques At a Former Petrochemical Plant Site. Environmental Technology 25:847-860.
    Presents an evaluation designed to provide information on reliability and selection of appropriate methods for soil gas sampling and analysis. The evaluation was based on a literature review of data and methods, and experiments completed as part of the research study.
  • Jewell, Kenneth P. and J.T. Wilson. 2011. A New Screening Method for Methane in Soil Gas Using Existing Groundwater Monitoring Wells. Groundwater Monitoring & Remediation 31(3): 82-94.
    This study develops and evaluates a protocol to sample soil gas from groundwater monitoring wells that have some portion of their screen in the vadose zone. Using conventional groundwater monitoring wells as an alternative to installation of soil gas probes proved to be cost-effective and provided reliable results.
  • McAlary, Todd, Paul Nicholson, Lee Yik, David Bertrand, and Gordon Thrupp. 2010. High Purge Volume Sampling - A New Paradigm for Subslab Soil Gas Monitoring. Groundwater Monitoring and Remediation 30:73-85.
    Presents a new method of monitoring that is based on a concept of integrating samples over a large volume of soil gas extracted from beneath the floor slab of a building to provide a spatially averaged subslab concentration.
  • McHugh, Thomas, Robin Davis, George DeVaull, Harley Hopkins, John Menatti, and Tom Peargin. 2010. Evaluation of Vapor Attenuation at Petroleum Hydrocarbon Sites: Considerations for Site Screening and Investigation. Soil and Sediment Contamination 19:725-745.
    A framework for the evaluation of vapor intrusion at petroleum hydrocarbon sites that involves simple screening for preferential pathways at sites with sufficient vertical separation between the building and the source, but a more intensive investigation at sites with petroleum sources in closer proximity to the building.

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Site Characterization and Conceptual Site Model Development

The resources below provide information about site characterization, for sites where PVI may be a concern.

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Models and Modeling

The resources below provide information about conceptual site model development, for sites where PVI may be a concern.

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  • Abreu, Lilian, and Paul Johnson. 2005. Effect of Vapor Source-Building Separation and Building Construction on Soil Vapor Intrusion as Studied with a Three-Dimensional Numerical Model. Environmental Science and Technology 39:4550-4561.
    A three-dimensional numerical model of the soil vapor to indoor air pathway is developed and used as a tool to estimate relationships between the vapor attenuation coefficient, the ratio of indoor air concentration to source vapor concentration, and vapor source building lateral separation, vapor source depth, and building construction characteristics (depth of building foundation) for nondegrading chemicals.
  • Abreu, Lilian, and Paul Johnson. 2006. Simulating the Effect of Aerobic Biodegradation on Soil Vapor Intrusion into Buildings - Influence of Degradation Rate, Source Concentration, and Depth. Environmental Science and Technology 40:2304-2315.
    Uses a three-dimensional multicomponent numerical model to study steady-state vapor intrusion scenarios involving aerobically biodegradable chemicals.
  • Abreu, Lilian, Robert Ettinger, and Todd McAlary. 2009. Simulated Soil Vapor Intrusion Attenuation Factors Including Biodegradation for Petroleum Hydrocarbons (PDF). Groundwater Monitoring and Remediation 29:105-117. (13 pp, 567 K)
    Describes results from three-dimensional numerical model simulations of vapor intrusion for petroleum hydrocarbons to assess the influence of aerobic biodegradation on the attenuation factor for a variety of source concentrations and depths for residential buildings with basements and slab-on-grade construction.
  • American Petroleum Institute (API). 2009. Simulating the Effect of Aerobic Biodegradation on Soil Vapor Intrusion into Buildings – Evaluation of Low Strength Sources Associated with Dissolved Gasoline PlumesPublication No. 4775; American Petroleum Institute: Washington, D.C.
  • American Petroleum Institute (API). 2010. BioVapor Indoor Vapor Intrusion Model.
  • Bekele, D.N., R. Naidu, M. Bowman, and S. Chadalavada. 2013. Vapor Intrusion Models for Petroleum and Chlorinated Volatile Organic Compounds: Opportunities for Future Improvements. Vadose Zone Journal 12(2).
  • Bozkurt, Ozgur, Kelly Pennell, and Eric Suuberg. 2009. Simulation of the Vapor Intrusion Process for Nonhomogeneous Soils Using a Three-Dimensional Numerical Model (PDF). Groundwater Monitoring and Remediation 29:92-104. (13 pp, 1.0 MB)
    Presents model simulation results of vapor intrusion into structures built atop sites contaminated with volatile or semivolatile chemicals of concern. A three-dimensional finite element model was used to investigate the importance of factors that could influence vapor intrusion when the site is characterized by nonhomogeneous soils.
  • Davis, G.B., M.G. Trefry, and B.M. Patterson. 2009. Petroleum Vapour Model Comparison, CRC for Contamination Assessment and Remediation of the Environment, Technical Report Number 9, 24p.
  • DeVaull, George. 2007. Indoor Vapor Intrusion with Oxygen-Limited Biodegradation for a Subsurface Gasoline SourceEnvironmental Science and Technology 41:3241-3248.
    Presents a mathematical model that simulates PVI and includes aerobic biodegradation.
  • EPA. 2005. Uncertainty and the Johnson-Ettinger Model for Vapor Intrusion Calculations (EPA/600/R-05/110) (PDF)(43 pp, 645 K)
  • Hers, Ian, Reidar Zapf-Gilje, Dyfed Evans, and Loretta Li. 2002. Comparison, Validation, and Use of Models for Predicting Indoor Air Quality from Soil and Groundwater ContaminationSoil and Sediment Contamination 11:491-527.
    Evaluates different soil vapor transport to indoor air screening models through a review of model characteristics and sensitivity, and through comparisons to measured conditions at field sites.
  • Hers, Ian, Reidar Zapf-Gilje, Paul Johnson, and Loretta Li. 2003. Evaluation of the Johnson and Ettinger Model for Prediction of Indoor Air QualityGroundwater Monitoring and Remediation 23:119-133.
    A comprehensive evaluation of the Johnson and Ettinger (J&E) model through sensitivity analysis, comparisons of model predicted to measured vapor intrusion for 11 petroleum hydrocarbon and chlorinated solvent sites, and a review of radon and flux chamber studies. The paper highlights the importance in using appropriate input parameters for the J&E model and discusses the regulatory implications associated with use of the J&E model to derive screening criteria.
  • Johnson, Paul, and Robert Ettinger. 1991. Heuristic Model for Predicting the Intrusion Rate of Contaminant Vapors into BuildingsEnvironmental Science and Technology 25:1445-1452.
    Presents a heuristic model of screening level calculations for predicting vapor intrusion rates and includes sample calculations for a range of parameter values to illustrate use of the model and the relative contributions of individual transport mechanisms.
  • Johnson, Paul. 2005. Identification of Application-Specific Critical Inputs for the 1991 Johnson and Ettinger Vapor Intrusion AlgorithmGroundwater Monitoring and Remediation 25:63-78.
    Outlines the relationships between model inputs and outputs so that users can identify critical inputs when applying the Johnson and Ettinger model.
  • Lahvis, M. 2011. Vapour Transport from Soil and Groundwater to Indoor Air: Analytical Modeling Approach in Vapor Emissions to Outdoor Air and Enclosed Spaces for Human Health Risk Assessment: Site Characterization, Monitoring, and Modeling. S. Saponaro, E. Sezenna, L. Bonomo, Eds., Nova Science Publishers, Inc., New York. pp. 91-112.
  • Ma, J., H. Luo, G.E. DeVaull, W.G. Rixey, and P.J.J. Alvarez. 2014.  Numerical Model Investigation for Potential Methane Explosion and Benzene Vapor Intrusion Associated with High­Ethanol Blend Releases. Environmental Science & Technology 48(1):474-481.
  • Mills, W.B., S. Liu, M.C. Rigby, and D. Brenner. 2007. Time-Variable Simulation of Soil Vapor Intrusion into a Building with a Combined Crawl Space and Basement. Environmental Science and Technology 41(14):4993-5001.
  • Olson, David and Richard Corsi. 2001. Characterizing Exposure to Chemicals from Soil Vapor Intrusion Using a Two-Compartment ModelAtmospheric Environment 35:4201-4209.
    Discusses the use of a two compartment model (one for the basement and one for the remainder of the house) to characterize subsurface transport on the indoor environment. A field study was completed to quantify parameters associated with the two compartment model, such as soil gas intrusion rates and basement to ground floor air exchange rates. Results indicate that exposures are highly dependent on gas intrusion rates, basement ventilation rate, and fraction of time spent in the basement.
  • Park, H. 1999. A Method For Assessing Soil Vapor Intrusion From Petroleum Release Sites: Multi-Phase/Multi-Fraction Partitioning (PDF). Global Nest 1:195-204. (10 pp, 268 K)
    A model and spreadsheet based numeric approximation for computing risk-based soil cleanup levels for the indoor air exposure pathway at petroleum-contaminated sites.
  • Parker, Jack. 2003. Modeling Volatile Chemical Transport, Biodecay, and Emission to Indoor Air (PDF). Groundwater Monitoring and Remediation 23:107-120. (14 pp, 1.3 MB)
    Presents a model for estimating vapor concentrations in buildings because of volatilization from soil contaminated by non-aqueous phase liquid (NAPL) or dissolved contaminants in ground water. The model considers source depletion, diffusive-dispersive transport of the contaminants and of oxygen and oxygen limited contaminant biodecay.
  • Pennell , Kelly, Ozgur Bozkurt, and Eric Suuberg. April 2009. Development and Application of a Three-Dimensional Finite Element Vapor Intrusion Model SourceJournal of the Air and Waste Management Association 59:447-460.
    A three-dimensional finite element model of soil vapor intrusion, including the overall modeling process and the stepwise approach.
  • Provoost, Jeroen, Annelies Bosman, Lucas Reijnders, Jan Bronders, Kaatje Touchant, and Frank Swartjes. 2009. Vapour Intrusion from the Vadose Zone - Seven Algorithms ComparedJournal of Soils and Sediments 10:473-483.
    Evaluates seven screening level algorithms, predicting vapor intrusion into buildings as a result of vadose zone contamination, regarding the accuracy of their predictions and their usefulness for screening purpose. The algorithms with the highest accuracy for predicting the indoor air concentration were the Johnson-Ettinger model and Vlier–Humaan algorithms.
  • Ririe, G.T., R.E. Sweeney, S.J. Daugherty, and P.M. Peuron.  1998. A Vapor Transport Model that is Consistent with Field and Laboratory Data, in, Petroleum Hydrocarbons and Organic Chemicals in Groundwater: Prevention, Detection, and Remediation Conference, Groundwater  Association  Publishing, Houston, Texas,  pp.299-308.
  • Ririe, G.T., R.E. Sweeney, and S.J. Daugherty. 2002. A Comparison of Hydrocarbon Vapor Attenuation in the Field with Predictions from Vapor Diffusion Models. Soil and Sediment Contamination 11(4):529-544.
  • Sanders, Paul and Nazmi Talimcioglu. 1997. Soil-to-Indoor Air Exposure Models for Volatile Organic Compounds: The Effect of Soil MoistureEnvironmental Toxicology and Chemistry 16:2597-2604.
    Discusses two finite-source models used to study the effect of soil moisture on indoor air concentrations and inhaled doses. Indoor air concentrations and inhaled doses for the model contaminant varied by up to seven orders of magnitude, depending on the soil moisture conditions and whether or not contaminant degradation was considered.
  • Tillman, Fred and James Weaver. 2007. Parameter Sets for Upper and Lower Bounds on Soil-to-Indoor-Air Contaminant Attenuation Predicted by the Johnson and Ettinger Vapor Intrusion ModelAtmospheric Environment 41:5797-5806.
    Used EPA recommended ranges of parameter values for nine soil-type, source depth combinations to identify input parameter sets that correspond to best and worst case results of the Johnson and Ettinger model. The results established the existence of generic best and worst case parameter sets for maximum and minimum exposure for all soil types and depths investigated.
  • Tillman, Fred and James Weaver. July 2006. Uncertainty from Synergistic Effects of Multiple Parameters in the Johnson and Ettinger (1991) Vapor Intrusion ModelAtmospheric Environment 40:4098-4112.
    Presents results of multiple parameter uncertainty analyses using the Johnson and Ettinger model to evaluate risk to humans from vapor intrusion.
  • Turczynowicz, L. and N. I. Robinson. 2007. Exposure Assessment Modeling for Volatiles -- Towards an Australian Indoor Vapor Intrusion Model. Journal of Toxicology and Environmental Health Part A 70(19):1619-1634.
  • Yao, Yijun, Rui Shen, Kelly Pennell, and Eric Suuberg. March 2011. Comparison of the Johnson-Ettinger Vapor Intrusion Screening Model Predictions with Full Three-Dimensional Model ResultsEnvironmental Science and Technology 45:2227-2235.
    Compares predictions from a three-dimensional model of vapor intrusion, based upon finite element calculations of homogeneous soil scenarios, with the results of the Johnson-Ettinger model. Results suggest that there are conditions under which the model predictions might be reasonable but that there are also others in which the predictions are low as well as high.

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Mitigation and Remediation of PVI

The resources below provide information about the mitigation and remediation of petroleum vapor intrusion (PVI).

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  • Chen, Wenhao, Jianshun Zhang, and Zhibin Zhang. 2005. Performance of Air Cleaners for Removing Multiple Volatile Organic Compounds in Indoor Air. ASHRAE Transactions 111:1101–1114.
    Evaluates 15 air cleaners' performance in terms of single-pass efficiency and the clean air delivery rate in a mixture of 17 volatile organic compounds (VOCs).
  • EPA. October 2008. Engineering Issue: Indoor Air Vapor Intrusion Mitigation Approaches (PDF)(49 pp, 594 K) EPA/600/R-08-15.
    This paper is focused on the mitigation of vapor intrusion to prevent human exposure to anthropogenic soil and ground water contaminants. This document is designed to provide sufficient information to allow the reader to understand the range of mitigation technologies available. The document also provides information on selecting appropriate technologies in consultation with qualified engineering and risk management professionals.

Guidance

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EPA Guidance

This section provides PVI-related guidance documents issued by EPA.

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State Guidance

This section provides PVI-related guidance documents issued by state agencies.

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Alaska Alabama Arizona California Colorado Delaware Hawai'i Idaho Illinois Indiana Iowa Kansas Kentucky Maine

Maryland

Massachusetts Michigan Minnesota Missouri Montana Nebraska New Hampshire New Jersey New York North Carolina

Nevada

Ohio Oregon Pennsylvania South Dakota Tennessee Utah Vermont Virginia Washington West Virginia Wisconsin Wyoming

The following link provides access to state vapor intrusion guidance documents. They are organized geographically through a clickable map of the U.S., in alphabetical order, or arranged by topic:

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Other Guidance

This part of the PVI compendium provides PVI-related guidance documents issued by federal agencies and other groups.

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