VOC Sink Behaviour on Building Materials – Model Evaluation

Abstract

The event of 11 September 2001 underscored the need to study the vulnerability of buildings to weapons of mass destruction, including chemical, biological, physical and radiological agents. Should these agents be released inside a building, they would interact with interior surfaces, building materials and furnishings, and could remain for a long period in an indoor environment. This study provides insights into the sink effect and absorption mechanisms of volatile organic compounds (VOCs) in indoor environments. In this study, the sink effect was investigated with building materials (e.g. painted gypsum wallboard, vinyl flooring, carpet and mortar) and VOCs, ethylbenzene, 1-butanol, decane and dodecane, which were used as surrogates of toxic chemicals. Vinyl flooring has the strongest sink for ethylbenzene and dodecane. The sink experimental data were employed to evaluate the Langmuir-isotherm and diffusion sink models. Test data were also compared to a no-sink model. The sorption and desorption rate constants for the Langmuir-isotherm model were obtained. Mass balance was analysed. There were strong correlations between equilibrium partition coefficients from the Langmuir-isotherm model and equilibrium partition coefficients and the effective diffusion coefficients from the sink diffusion model.

Impact of material emissions and sorption of volatile organic compounds on indoor air quality in a low energy building: Field measurements and modeling

“…This set covers the range of variability observed in sorption parameters in the literature (see Table 1). [47][48][49][50][51] The other modeling work aims to compare the measured profiles of selected VOCs with the modeled profiles. In the following, infiltration air exchange rate (IAER) will refer to the ventilation OFF conditions and the ventilation air exchange rate (VAER) to the ventilation ON conditions, knowing that a minor part of this rate is also due to infiltration.…”

“…The sorption parameters for gypsum board (GB) determined previously ( k a GB = 1.3 m h −1 ; k d GB = 1.7 h −1 ) have been used and varied separately by a factor between 0 and 100 for the different conditions, as multiplying both k a and k d by the same factor leads to a similar K e ratio and similar modeled profiles. This set covers the range of variability observed in sorption parameters in the literature (see Table ) …”

Material Emissions and Indoor Simulation

“…Liu et al. [79] studied the various sink effects of some VOCs as surrogates to chemical warfare agents and toxic industrial chemicals of some building materials (carpets, wallboards, vinyl flooring and mortars) in small chambers. The gas phase concentrations of the potential contaminants were predicted using Langmuir-isotherm and diffusion models as function of time, validated by chamber experiments.…”

Robust Nonfitting Way To Determine Mass Diffusivity and Initial Concentration for VOCs in Building Materials with Accuracy Estimation

“…The continuing concern about indoor emission of volatile organic compounds (VOCs) has heightened the need for characterizing organic emission from building materials. − Of particular interest and difficulty is the determination of the three characteristic parameters of emitting materials: diffusivity D , , initial concentration C 0 , , and air-material partition coefficient K . − These parameters are key inputs of mass diffusion models for predicting organic emission in indoor environments. − Various methods for estimating these parameters have been proposed, among which a small but important point is that models are generally fit to measured data to obtain parameter estimates. − The methods using steady-state diffusion models usually require a relatively long testing time to approach a quasi-steady-state; , thus methods built on a transient concentration profile have been paid considerable attention in recent years. − …”