Effects of airflow on VOC emissions from "wet" coating materials: Experimental measurements and numerical simulation

The impact of airflow on volatile organic compound (VOC) emissions from "wet" materials has long been noticed. However, a comprehensive mass transfer model that can predict such an impact has not been reported. The objective of this research was to fill that gap. First, we measured the VOC emissions of "wet" coating materials (a decane and a wood stain) using a small-scale (0.4 m³) and a full-scale (55 m³) environmental chamber under different airflow conditions. A numerical model was then developed to numerically simulate the "wet" material emissions. The model considers VOC mass transfer in the air and material-air interface, diffusion in the material film, and diffusion in the substrate. The results from experimental measurements indicate that local airflow has impacts on "wet" material emissions, especially during the early stage. The numerical model developed can predict emissions under different flow conditions with reasonable accuracy. Numerical simulations have further confirmed that the emissions from "wet" materials applied to an absorptive substrate are dominated by evaporation at the beginning and internal diffusion afterwards, which had been speculated based on previous experimental data. The numerical model has the potential to simulate "wet" material emissions in actual building environments based solely on the small-scale chamber data.