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Total Human Exposure Risk Database and Advance Simulaiton Environment
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THERdbASE is no longer supported by EPA and is no longer available as download.
THERdbASE is a collection of databases and models that are useful to assist in conducting assessments of human exposure to chemical pollutants, especially for inhalation exposure to indoor airborne volatile organic compounds (VOCs). THERdbASE is a user-friendly Windows-type application for personal computers. It contains eleven (11) different human exposure-related modeling modules and the data necessary to use these models. The models within THERdbASE, some of which can be run in a coordinated manner, include the following, with model numbers corresponding to those in THERdbASE:
101. Subsetting Activity Pattern Data
102. Locations Patterns - Simulated
103. Source - Timed Application
104. Source - Instantaneous Application
105. Indoor Air - 2 Zones
106. Indoor Air - N Zones
107. Exposure - Inhalation - BEAM [Benzene Exposure Assessment Model]
108. Exposure - Inhalation - Multiple Chemicals
109. Dose - Dermal - Film Thickness
110. Scenario - Dose - Inhalation/Dermal
201. Soil Exposure/Dose Assessment
Most of the models in THERdbASE can conduct either single-scenario or Monte Carlo simulations. Models 101 and 102 are used to select demographic subpopulations and simulate the activity and location sequences of people within that subpopulation. Simulations are based on data from human activity surveys. Those data are stored within datafiles within THERdbASE. Models 103 and 104 simulate the release of volatile organic compounds, over either a user-selected period of time, or in an instantaneous release, respectively, into indoor air. Models 105 and 106 simulate the airborne concentrations of VOCs in multi-zone indoor environments. The simulated VOCs are those whose emissions were simulated in Models 103 and 104. Models 107 and 108 simulate the inhalation exposure to benzene or other VOCs, respectively, of people as they inhabit multiple environments as defined by their location and activity patterns. Model 109 simulates peoples' dermal (skin) exposure to chemicals. Model 110 combines inhalation and dermal exposure simulations. Model 201 simulates exposure to chemical contaminants on soil.
A significant limitation of THERdbASE is the limited ability of users to import their own data. Many of the models are constrained to using the existing databases that are also a built-in part of THERdbASE.
THERdbASE was created as a research and development prototype of a user-friendly software system for linking data and models in performing human exposure and risk assessments. No further versions or improvements to THERdbASE are planned by the EPA.
The next generation of EPA's human exposure data will be made available in an Internet-accessible system referred to as HEDS, the Human Exposure Data System. HEDS will not contain exposure models. Further developments of the exposure modeling concepts of THERdbASE, using other program names, are being pursued by Info Scientific Inc. of Henderson, Nevada.