A correlation between partition coefficients, K, of dry building material and liquid molarvolume of volatile organic compounds (VOCs) in it, v1, is presented. Experiment fordetermining the partition coefficients of the target VOCs including benzene, toluene,ethylbenzene for two kinds of building materials was conducted by a method developedby us. The experimental data verified the correlation. Also the correlation was supportedwell by the experimental data in the literature. It is found that the correlation can predictthe partition coefficients of VOCs with similar structure in the same building material

Through the observation of the pore structure and mercury intruding porosimetry (MIP) experiments of some typicalporous building materials, we found that the diffusion coefficient of the material can be expressed by that of arepresentative elementary volume (REV) in which the pore structure can be simplified as a connection in series of macroand meso pores. Based upon that, a macro-meso two-scale model for predicting the diffusion coefficient of porous buildingmaterials is proposed. In contrast to the traditional porous mass transfer model for determining the diffusion coefficientdescribed in the literature [Blondeau, P., Tiffonnet, A.L., Damian, A., Amiri, O., Molina, J.L., 2003. Assessment ofcontaminant diffusivities in building materials from porosimetry tests. Indoor Air 13, 302-310; Seo, J., Kato, S., Ataka, Y.,Zhu, Q., 2005. Evaluation of effective diffusion coefficient in various building materials and absorbents by mercuryintrusion porosimetry. In Proceedings of the Indoor Air, Beijing, China, pp. 1854-1859, the proposed model relates thevolatile organic compound (VOC) diffusion coefficient of building material not only to the porosity of the buildingmaterial, but also to the pore size distribution and pore connection modes. To verify the model, a series of experiments ofVOC emissions of three types of medium-density board were conducted. The comparison of the model and experimentalresults shows that the proposed model agrees much better with the experimental results than the traditional models in theliterature. More validation for other building materials is needed. The proposed model is useful for predicting the VOCdiffusion coefficient of porous building materials and for developing low VOC emission building materials.

The investigation of the photocatalytic oxidation (PCO)of multicomponent volatile organic compounds (VOCs)is very important to the application of PCO technology,because there is seldom a single VOC component in indoorair. In this paper, the characteristics of binary indoorVOCs, toluene and benzene, were experimentally studiedusing a mass transfer based method that we developed.The concentration ranges for toluene and benzene were 4.48-27.4mg/m3 and 1.82-4.08mg/m3, respectively. Wefound the following: (1) the PCO of each individual contaminantstudied obeys the unimolecular form of theLangmuir-Hinshelwood (L-H) rate form; (2) the PCO ofthe binary contaminants follow the competitive adsorptionL-H rate form; (3) the reaction-coefficient for PCO ofindividual contaminants differs from that in the competitiveadsorption L-H rate form; and (4) the componentimpact factor of A to B, put forward in this paper, is auseful parameter describing the influence of A on thereaction coefficient of B, and it was found that the impactfactor of toluene (a chemically active component) onbenzene (a chemically stable component) is high, and theimpact factor of benzene on toluene is low.

The diffusion coefficient, D, partition coefficient, K, and the initial volatile organic compounds (VOCs) in dry buildingmaterials, are the three key parameters used to predict the VOC emissions. D and K may be strongly affected bytemperature. We have developed a new and simple method, the C-history method, to measure the diffusion coefficient, Dand the partition coefficient, K of formaldehyde in dry building materials at temperatures of 18, 30, 40 and 50℃. Themeasured variations of the diffusion coefficients and the partition coefficients with temperature for particle board, vinylfloor, medium-and high-density board are presented. A formula relating the partition coefficient and related factors isobtained through analysis. This formula can predict the partition coefficient in principle and provide an insight for fittingexperimental data, and it agrees well with the experimental results.

Based on the most recently published mass transfer model of volatile organic compound (VOC) emissions from drybuilding materials, it is found that the dimensionless emission rate and total emission quantity are functions of just fourdimensionless parameters, the ratio of mass transfer Biot number to partition coefficient (Bim/K), the mass transfer Fouriernumber (Fom), the dimensionless air exchange rate (Nd2/Dm) and the ratio of building material volume to chamber orroom volume (Ad/V). Through numerical analysis and data fitting, a group of dimensionless correlations for estimating theemission rate from dry building materials is obtained. The predictions of the correlations are validated against thepredictions made by the mass transfer model. Using the correlations, the VOC emission rate from dry building materialscan be conveniently calculated without having to solve the complicated mass transfer equations. Thus it is very simple toestimate VOC emissions for a given condition. The predictions of the correlations agree well with experimental data in theliterature except in the initial few hours. Furthermore, based on the correlations, a relationship between the emission ratesof a material in two different situations is deduced. With this relationship, the results for a given building material in a testchamber can be scaled to those under real conditions, if the dimensionless parameters are within the appropriate region forthe correlations. The relationship also explicitly explains the impacts of air velocity, load ratio, and air exchange rate onthe VOC emission rate, which determines the feasibility of assuming that the VOC emission rates in real conditions are thesame as those in the test chambers.