A spatial fractional diffusion model for predicting the characteristics of VOCs emission in porous dry building material.

Volatile organic compounds (VOCs) concentrations of dry building materials can significantly affect the quality of indoor air. In this paper, a spatial fractional diffusion model is established by introducing fractional Fick's law, based on the fact that the pore structure of porous building materials has a strongly impact on VOCs diffusion. Furthermore, the areal porosity of the material is drawn into the convection mass transfer equation.