EFFECTIVENESS OF TITANIUM DIOXIDE PHOTOCATALYST FILTERS FOR CONTROLLING BIOAEROSOLS

Currently, photocatalytic oxidation (PCO) is considered to be an effective process for removing and destroying low- level pollutants, which makes it a strong candidate for indoor air quality applications. Our study evaluated the titanium dioxide (TiO2) filter media in controlling bioaerosols in a laboratory test chamber. The influences of microorganism species, relative humidity, and face velocity on the germicidal effectiveness of a TiO2-coated filter with 365 nm 8 W and 36 W blacklight irradiation were investigated. A Collison nebulizer generated Escherichia coli (E. coli), Bacillus subtilis (B. subtilis) endospores, yeast cells of Candida famata (C. famata) var. flareri, and spores of Penicillium citrinum (P. citrinum). The PCO control effectiveness was determined as the ratio, N-S/N-0, where N-S and N-0 were the culturable concentrations collected by an Andersen one-stage sampler downstream of TiO 2-coated filters with and without blacklight irradiation, respectively. Our results demonstrated that there were no significant differences in microorganism penetrations for TiO2-coated filters with and without blacklight irradiation. It was recommended that TiO2 filter media used in this study did not perform as a good germicidal capability for airborne microorganisms