Wet scrubbers are very commonly used industrial equipments in removing particles from hot flue gases based on particle wetting mechanisms. Spray towers are simple and economical, hence used in small and medium scale industries for scrubbing particulate and gaseous pollutants. Even though the primary mechanisms of scrubbing of particulate are known, the exact mechanism is not understood yet. Prediction of particulate efficiency is very important for the selection of pollution control equipment. Hence verification of the overall efficiency achieved by any spray scrubbing system based on theoretical models is essential. In this paper an attempt has been made to theoretically predict the efficiency for a spray tower using single twin-fluid air-assist atomizer scrubbing wide size range (1-5 mu m) of particulate matter. Results indicate that a maximum of overall theoretical removal efficiencies for the particle sizes 4-5 mu m achieved by the spray tower was nearly 99.8%. A comparison of the experimental and theoretical efficiencies has been made and systematically analyzed. (C) 2008 Elsevier B.V. All rights reserved.