An analytical model for VOCs emission from dry building materials

A new analytical model for VOCs emission is presented in this paper. This model considers both the diffusion in the materials and the mass transfer through the air boundary layer. Compared to other models capable of accounting for those two mechanisms, this model is fully analytical. A general characteristic equation is developed, which would reduce to that of Little et al. (Atmos. Environ. 28 (1994) 227) when the gas-phase mass transfer coefficient becomes infinite. Thus, with the current model the concentration in the air can be solved conveniently without iteration. Results of the present model show a good agreement with the experimental data while the model of Little et al., overestimated the concentration in the air. Also, further analysis on this model shows that the concentration in the air increases with the increase of the gas-phase mass transfer coefficient in the early stage. And the normalization of the concentrations in the materials and in the air shows that five dimensionless numbers are needed to determine the characteristics of VOCs transport from the building materials to the air.