The increasingly stringent and expanding array of regulatory controls to reduce potentially toxic emissions associated with waste burning ave driving the cleanup of these emissions away from the usually costly rudimentary practices to systems in which the cleanup process can be efficiently controlled and modified to accommodate changes In regulatory requirements. The technology of first: choice is the Dry Sorbent Injection (DSI) of flue gases. In this work, the collection efficiency of a volatile organic compound (VOC) from flue gases on a powdered activated carbon adsorbent is investigated. Results from pilot scale tests ave compared with the results generated from a theoretical model developed for DSI. The model uses a transient diffusion equation for particles with adsorption represented using a Freundlich isotherm and a balance equation for the bulk gas phase VOC fraction. The cases of injection of adsorbing particles using the geometrical mean diameter and the actual particle size distribution are investigated.