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i-SVOC -- A simulation program for indoor SVOCs (Version 1.0)
Citation:
Guo, Z. i-SVOC -- A simulation program for indoor SVOCs (Version 1.0). US Environmental Protection Agency, Cincinnati, OH, EPA/600/C-13/290, 2013.
Impact/Purpose:
This research marks a significant step forward in modeling indoor SVOCs. It allows the users to estimate the SVOC distributions in the indoor environment as a function of time. This program willy be useful in the following areas: (1) It can be used as a stand-alone simulation program to obtain information that the current equilibrium models cannot provide. For example, i-SVOC can evaluate the effectiveness of certain pollution remediation methods such as variable ventilation rates, source removal, and source encapsulation. (2) It can help reduce the uncertainties in the existing multimedia models. For instance, for the SVOCs with large solid-air partition coefficients, the instantaneous equilibrium assumption tends to overestimate the particle-phase SVOC concentrations in room air. Program i-SVOC can provide an estimate of the degree of sorption saturation (DSS), which can be used as an adjusting factor. (3) It can be used as a front-end component for the stochastic exposure models, such as the EPA’s SHEDS models. Program i-SVOC can provide estimates of the SVOC distributions in indoor media in the absence of experimental measurements. On the other hand, this program does not solve all the problems associated modeling indoor SVOCs. Future research should focus on reducing the uncertainties in the model input by improving the parameter estimation methods for several key parameters for modeling indoor SVOCs.
Description:
Program i-SVOC estimates the emissions, transport, and sorption of semivolatile organic compounds (SVOCs) in the indoor environment as functions of time when a series of initial conditions is given. This program implements a framework for dynamic modeling of indoor SVOCs developed by the author, and covers six types of indoor compartments: air (gas phase), air (particle phase), sources, sinks (i.e., sorption by interior surfaces), contaminant barriers, and settled dust. Potential applications of this program include: (1) use as a stand-alone simulation program to obtain information that the current equilibrium models cannot provide, including evaluation of the effectiveness of certain pollution mitigation methods such as variable ventilation rates, source removal, and source encapsulation; (2) reducing the uncertainties in the existing multimedia models; and (3) use as a front-end component for stochastic exposure models to provide information about the SVOC distribution in indoor media in the absence of experimental data. This program is intended for advanced users, who are involved in and familiar with indoor environmental quality (IEQ) modeling or indoor exposure assessment. Because dynamic modeling of SVOCs in indoor media is a relatively new research field, a number of issues need to be resolved in future research. For example, efforts should be made to reduce the uncertainties in parameter estimation. There is a need to develop a data and knowledge base for key parameters for modeling indoor SVOCs, including, but not limited to, solid-air partition coefficient, solid-phase diffusion coefficient, and gas-phase mass transfer coefficient.