STP1205

    Critical Evaluation of the Diffusion Hypothesis in the Theory of Porous Media Volatile Organic Compound (VOC) Sources and Sinks

    Published: Jan 1993


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    Abstract

    Recently, reports by both the U.S. Environmental Protection Agency (EPA) and a study committee of the Commission of the European Communities have alluded to diffusion mechanisms that may play a role in Volatile Organic Compound (VOC) interactions with indoor sinks. This paper proposes three alternative, diffusion-limited mathematical models to account for this interaction, using the linear isotherm model as a reference point. Their taxonomy is keyed to the nature of the vapor-sink interface. While the linear isotherm model gave an adequate description of data when a pillow-sink was challenged with ethylbenzene, a new single-parameter diffusion model gave a much improved description of data when the same pillow-sink was challenged with perchloroethylene. A hybrid, sorption/desorption, diffusion-limited model was the only plausible model when a carpet-sink was challenged with ethylbenzene. Some new computational aids, particularly intervalweighted least squares, are introduced in the context of model validation.

    Keywords:

    mathematical model, weighted least squares, linear isotherm, pillow, carpet, ethylbenzene, perchloroethylene, indoor air


    Author Information:

    Dunn, JE
    Professor and chairman, and research assistant, University of Arkansas, Fayetteville, AR

    Chen, T
    Professor and chairman, and research assistant, University of Arkansas, Fayetteville, AR


    Paper ID: STP13100S

    Committee/Subcommittee: D22.05

    DOI: 10.1520/STP13100S


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