A Framework for Modelling Non-Steady-State Concentrations of Semivolatile Organic Compounds Indoors – I: Emissions from Diffusional Sources and Sorption by Interior Surfaces

Abstract

Over the past two decades, more than 20 mass transfer models have been developed for building materials, furnishings, and consumer products as contaminant sources, sinks, and barriers. While these models have greatly improved our understanding of contaminant movements in buildings, their applications in the real world have been somewhat limited because of the incompatibility and computational complexity of the models. In this paper, a framework is proposed for modelling the dynamic concentrations of semivolatile organic compounds in indoor media. Based on a discretization method, which transfers continuous models into discrete counterparts, this framework can perform the functions of the existing mass transfer models and, at the same time, solves the model incompatibility problem and reduces the computational complexity. This framework complements and supplements the existing multimedia semivolatile organic compound models by providing more details of the distribution of semivolatile organic compounds among indoor media, helping check the validity of certain assumptions that have been used in those steady-state models, and providing more flexibility to allow evaluation of risk management options such as source removal, encapsulation, and variable ventilation rate. This framework will be described in two parts. Part I, this paper, discusses the representation of diffusional sources and sorption by interior surfaces. Interactions of semivolatile organic compounds with particulate matter will be discussed in a subsequent publication.