An improved mechanism-based model for predicting the long-term formaldehyde emissions from composite wood products with exposed edges and seams

Emissions of formaldehyde from building materials and furniture can cause adverse health effects. Traditional models generally only consider emissions as a physical process that can be characterized by three key parameters: the initial emittable concentration, the diffusion coefficient and the partition coefficient. However, the physical-based model causes discrepancy in predicting long-term formaldehyde emissions for the cases where chemical reaction (i.e., hydrolysis) occurs over time. In this study, an improved mechanism-based model was developed by combining the chemical reaction process with a physical mass transfer process to more accurately predict the long-term emission behaviors. The chamber testing data of formaldehyde emissions from exposed edges and seams of a laminate flooring product made with composite wood core for about 1.5 year was used to validate the model. Results indicate that the mechanism-based model characterizes well the long-term formaldehyde emissions from the tested material. Predictions of different models further demonstrate the advantages of this improved model compared with the physical model or with empirical models. This study is the first attempt to check the feasibility of including the chemical reaction term in emission modeling and to quantitatively explore the importance of its contribution to long-term formaldehyde emissions, which includes most of the indoor emissions from materials and furniture.