Volatile organic compound (VOC) adsorption by indoor materials will reduce peak concentrations, and subsequent desorption will prolong the presence of a compound indoors. Diffusion within materials plays an important role in this context. The purpose of this paper is to present two experimental set-ups to study VOC diffusion, and to show corresponding experimental results. The Field and Laboratory Emission Cell (FLEC) is in both cases an integral part of the set-up. The mass flow of VOC mixtures across gypsum board is studied. Diffusion of less polar VOCs in gypsum board can be fast (diffusion coefficients of 0.001-0.003 m(2) /h). Diffusion coefficients of chlorinated compounds are correlated with boiling points and molecular areas. Different compounds show similar diffusion properties.

• VOC transport
• VOC: measurement and identification