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BioVapor Indoor Vapor Intrusion Model

To download, review the terms and conditions and submit the form below.


BioVapor is a user-friendly spreadsheet implementation of an indoor vapor intrusion model with oxygen-limited biodegradation. The BioVapor model is a steady-state 1-D analytical model intended to provide the user with an improved understanding of the potential effect of vadose zone aerobic biodegradation on the vapor intrusion pathway. The model does not directly account for spatial or temporal variations in parameter values. As a result, the model is not expected to provide highly accurate predictions when a single set of input parameter values is used to represent a single site. Rather, the model is expected to help the user identify a reasonable range of potential outcomes that result from varying key input parameter values to account for the uncertainty and variability associated with site conditions.

The user has three options for specifying the oxygen supply below the building foundation:

  1. direct entry of the depth of the aerobic zone below the building foundation,
  2. constant oxygen concentration below the building foundation, or,
  3. constant flow of atmospheric air below the building foundation.

For forward risk calculations, the model output provides:

  • Source Concentration
  • Source-to-Indoor Air Attenuation Factor
  • Predicted Indoor Air Concentration
  • Hazard Quotient
  • Risk Level

For backward risk calculations, the model output provides:

  • Critical Chemical (component of mixture having greatest impact on indoor air quality)
  • Target Hazard Quotient/Cancer Risk
  • Target Indoor Air Concentration
  • Soil Gas Source Concentration
  • Effective Saturation Limit (maximum theoretical soil gas concentration)
  • Groundwater Source Concentration
  • Effective Solubility

Subsurface Profiles of concentration vs. depth, and flux vs. depth, can be plotted.

System Requirements:

  • Microsoft Windows® Operating System XP/Vista
  • Microsoft Excel® 2003 or higher
To ensure proper operation, the user should install all software updates for Office Excel released by Microsoft®.

To Obtain the Software and User’s Guide

To download, review the terms and conditions and submit the form below.

Terms & Conditions

You expressly acknowledge and agree that the information contained in the software is being provided on an "as-is" basis, without warranty of any kind, express or implied, including without limitation any warranty regarding the accuracy or content of the information.

You further understand and agree that use of any and all information contained in the software is at your own sole risk.

You understand that the software is the copyrighted property of API and cannot be sold by you or another party without the prior written approval of API.

You release API, its members and employees, from any claims and damages you may have from accessing, using the information contained herein, and you agree to defend and indemnify API for any claims and/or damages that arise directly or indirectly from your use of the software or the information contained therein.

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