Based on the extraction method presented by Smith et al. (2008), this paper proposes an improved method, the multi-emission/flush regression method, to simultaneously determine the initial emittable concentration and the partition coefficient. Compared to the extraction method, the proposed method has the following advantages: (1) it is unnecessary for the target volatile organic compounds (VOCs) to emit completely from the material, thus greatly reducing experimental time; (2) it provides a simpler way to obtain the partition coefficients of VOCs for tested materials and can avoid the measurement uncertainties at low VOC concentrations which often occur during the last few cycles of the extraction method; (3) it does not require grinding the building material into powders thus making this method more convenient to use. Comparisons were made between the initial emittable VOC concentrations determined by the original extraction method and the proposed method. Results show good agreements between these two methods. To further validate the proposed method, the type of static chamber developed by Wang et al. (2006) was used to conduct the experiment for a type of medium density board, and formaldehyde was selected as the target compound. Based on the initial emittable concentration and partition coefficient obtained using the proposed method, and the diffusion coefficient obtained by the mercury intruding porosimetry, the chamber formaldehyde concentration was predicted and compared with the experimental measurements. Results show that the predicted chamber VOC concentration using the measured parameters agree well with the experimental data. (C) 2009 Elsevier Ltd. All rights reserved.

This paper describes a new experimental method for determining the initial concentrations of emittable volatile organic compounds (VOCs) from building materials and sorption isotherms for individual VOCs (IVOCs), which are required for modeling the VOC emission rates of building materials and assemblies. The method is also useful for the rapid screening of materials, enabling manufacturers to compare different production processes in order to reduce VOC emissions from their products. In this experimental method, material specimens were first ground into powder form in a sealed container and then allowed to emit in a recirculation loop to measure equilibrium concentrations at different levels, as well as the accumulated emission mass. Test results for particle board are presented, and compared to those obtained from a 30 day small chamber emission test for the same material. Results showed that the extraction method significantly increased the release of VOCs from the material and can be used to determine the total emittable initial VOC concentrations and the sorption isotherms for acetaldehyde and hexanal. For formaldehyde, the residual amount after the extraction test was found to be significant, and requires further investigation. Further studies are needed to shorten the test time and determine the accuracy and repeatability of the extraction method.

The objectives of this study were to compare the commercially available sorbent materials for removing typical indoor volatile organic compounds (VOCs) and to obtain data and experience that are useful to the development of a standard test method for sorbent media evaluation. A multichannel stainless steel air-cleaning technology testing system (ACTTS) was developed and used to test eleven pellet/granular-type sorbent media representing different base materials (coal, bituminous coal, coconut bamboo wood, and activated aluminas with potassium permanganate and activated carbon) for seven VOCs. Tests were conducted for VOCs including hexane, decane, toluene, tetrachloroethylene, 2-butanone, isobutanol, and D-limonene. Concentrations versus time during sorption and desorption periods were obtained. The sorbent media's performances were evaluated in terms of removal efficiency and removal capacity per unit of sorbent weight as a function of time, the 50% breakthrough time, and the half-life time removal capacity. In addition, repeatability of the test and the effect of flow rate on the test results were also investigated. The challenges of developing a standard test method and procedure for performance evaluation of pellet/granular-type sorbent media based on the experiences gained from the study are also discussed briefly in this paper.