An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Simulation Tool Kit for Indoor Air Quality and Inhalation Exposure (IAQX)

What is IAQX?

IAQX version 1.1 is an indoor air quality (IAQ) simulation software package that complements and supplements existing indoor air quality simulation (IAQ) programs.

Who Should Use the Model?

IAQX is for advanced users who have experience with exposure estimation, pollution control, risk assessment, and risk management.

What are the benefits of using IAQX?

There are many sources of indoor air pollution, such as building materials, furnishings, and chemical cleaners. Since most people spend a large portion of their time indoors, it is important to be able to estimate exposure to these pollutants.

IAQX helps users analyze the impact of pollutant sources and sinks, ventilation, and air cleaners. It performs conventional IAQ simulations to calculate the pollutant concentration and/or personal exposure as a function of time. It can also estimate adequate ventilation rates based on user-provided air quality criteria. This is a unique feature useful for product stewardship and risk management.

How does IAQX work?

IAQX consists of a general-purpose simulation program and a series of stand-alone, special-purpose programs. The general-purpose program performs multi-zone, multipollutant simulations and allows gas-phase chemical reactions. The four special-purpose programs contain more complex mass transfer models than the general-purpose programs, including:

  • Models for predicting volatile organic compound (VOC) emissions from solvent-based indoor coating materials based on product formulation
  • Models for indoor solvent spills
  • A model for VOC emissions from diffusion-controlled homogeneous slabs such as new carpet backing
  • A model for indoor particulate matter

System Requirements

The current version of IAQX is compatible with Windows XP, 7, and 8. To install:

  • Download the Installation files to your computer.

Installation file for IAQX 1.1 (ZIP)(6 MB)

  • Access the User's Guide from the Windows Start menu by clicking Start/All Programs/IAQX 1.1 or using the link below.
  • Select the GPS.EXE icon that appears on the desktop window.

Relevant Publications

Simulation Tool Kit for Indoor Air Quality and Inhalation Exposure (IAQX) User's Guide Version 1.0 (PDF) (86 pp, 1.26 K, About PDF)

Guo*, Z. Development of a Windows-Based Indoor Air Quality Simulation Software Package. Environmental Modelling and Software 15(4):403-410, (2000). doi:10.1016/S1364-8152(00)00020-7

Technical Contact

Xiaoyu Liu (