Study of effect of adsorptive building material on formaldehyde concentrations: development of measuring methods and modeling of adsorption phenomena.

UNLABELLED: In this paper, a method is developed to assess the performance of adsorptive building materials that are used for reducing indoor pollutant concentrations. Mass transfer has a great influence on the materials' performance. To control the mass transfer rate precisely in the performance test, the authors have developed the Boundary-Layer-Type Small Test Chamber in which airflow along the test materials can be controlled precisely. A new index of adsorption performance, the equivalent ventilation rate (Q(ads)), is defined that corresponds to the mass transfer coefficient when the surface pollutant concentration is zero. Modeling and experimental verification of adsorption were done, demonstrating the pollutant concentration decrease caused by adsorptive building materials. The pollutant reduction phenomena were modeled, including pollutant degradation by chemical reaction and adsorption in building materials. Adsorption tests of gypsum board containing a substance that decomposes HCHO within the board are reported. The adsorption rate of the gypsum board predicted by numerical analysis (CFD, Computational Fluid Dynamics) corresponds well with experimental results. PRACTICAL IMPLICATIONS: Development and verification of a method to measure the decrease in indoor pollutant concentration caused by an adsorptive building material are reported. Mass transfer has a great influence on the material's performance. The equivalent ventilation rate (Q(ads)) of the adsorption performance is defined as a new index that corresponds to the mass transfer coefficient. The equivalent ventilation rate (Q(ads)) can be used directly to compare the effect of pollutant concentration decrease via adsorption with the effect of ventilation.