Diffusion and sorption of volatile organic compounds in building materials- Impact on indoor air quality

Volatile organic compounds (VOCs) are frequent indoor air pollutants. Indoo r materials can act as buffers for VOCs, reducing peak concentrations but p rolonging the presence of compounds in the air. The purpose of this paper i s to present quantitative experimental results on diffusion and sorption of VOCs in indoor materials and to discuss the impact of these processes on i ndoor air quality. A two-flow system was chosen for the present study becau se this method allows mass flow across materials to be directly observed. F or some materials, effective diffusion coefficients were only 1 order of ma gnitude below what is found in air, Two types of concrete showed a very hig h sorption capacity for ethyl acetate, Steady-state calculations were perfo rmed within a model room. By considering various wall materials, the influe nces of diffusion and of sorption on the air quality of the room are discus sed. Regarding the case of gypsum board walls, it may be concluded that dif fusion through the material can contribute to reducing the room air concent ration, especially at low ventilation rates. The results indicate that sorp tion and diffusion processes can affect the ventilation requirements in suc h rooms.