Impact of temperature on the initial emittable concentration of VOC in building materials: Experiment and model development

Poor indoor air quality continuously emerges due to volatile organic compounds (VOC) emitted from building materials, which negatively affects people's comfort, health and productivity. Initial emittable concentration is one of the key parameters (diffusion coefficient, partition coefficient and initial emittable concentration) that influence the VOC emission from building materials, thus it is necessary to investigate its characteristics. Based upon the multi-emission/flush regression method proposed before, the initial emittable concentration of formaldehyde in a kind of medium density board at different temperatures has been studied. It is found that with the rising of temperature, the initial emittable concentration increases accordingly. However, the value is far less than the content measured by perforator method, which is recommended by Chinese standard (GB/T 17657-1999).The reason is ascribed to irreversible adsorption. That is to say, the content measured by perforator method is the total content of formaldehyde adsorbed into the medium density board, but most of them cannot emit out at normal conditions. By introducing the theory of heterogeneous adsorption, a model is developed to describe the ratio of the initial emittable concentration to the total content. It is indicated that the ratio increases with the rising of temperature. Predictions from the model agree with the experimental data very well. The study will be very helpful in revising the above-mentioned standard.