The evaluation of activities of two types of photocatalysts at inactivation/disintegration of microorganism aerosols A. S. Safatov 1 , S. A. Kiselev 1 , V. Yu. Marchenko 1 , A. A. Sergeev 1 , M. O. Skarnovich 1 , E. K. Emelyanova 1 , M. A. Smetannikova 1 , G. A. Buryak 1 and A. V. Vorontsov 2 1 Federal State Research Institution State Research Center of Virology and Biotechnology “Vector”, Novosibirsk Region, 630559, Koltsovo, Russia; 2 Boreskov Institute of Catalysis SB RAS, 630090, Novosibirsk, Russia Keywords: bioaerosols, photochemical processes, culturable microorganisms, air cleaning. Photocatalytic processes are more and more widely used to remove different pollutants including microorganisms from liquid and gaseous media. However, methods for evaluating the efficiency of photocatalysts at inactivation/disintegration of microorganisms in the liquid film have limitations at predicting their efficiency for microorganism-containing aerosols. The comparison of two types of photocatalysts was performed on Mycobacterium smegmatis bacterium and vaccinia virus using these new methods for evaluating the efficiency of photocatalysts at inactivation/disintegration of microorganisms in aerosols deposited on photocatalytic coatings. It has been shown that the photocatalyst based on platinized TiO 2 displays a higher activity at inactivation/disintegration of aerosols of both microorganisms than the photocatalyst based on “pure” titanium dioxide. 1. Introduction Photocatalytic processes are more and more widely used to remove molecular pollutants (Parmon, 1999; Shen and Ku, 2002; Sunada, et al., 1998; Vidal, et al., 1999) and suspended particles including different microorganisms (Kim, et al., 2006; Kuhn, et al., 2003; Lu, et al., 2003; Rincon, et al., 2001; Seven, et al., 2004; Sunada, et al., 1998; Sunada, et al., 2003; Vidal, et al., 1999; Vohra, et al., 2005; Zan, et al., 2007) from liquid and gaseous media. This is connected with the fact that photocatalytic devices can not only “remove” pollutants from air like usual adsorption filters do, but also destroy them (Kuhn, et al., 2003Lu, et al., 2003; Sunada, et al., 2003; Robertson, et al., 2005). When pollutants are removed from a liquid medium, there is no shortage of water molecules, which are necessary for efficient photocatalytic oxidation of pollutants; there are also no limitations on the pollutant transfer to the photocatalytic site where the pollutant meets the forming radicals (Huang, et al., 2000; Nadtochenko, et al., 2006; Rincon, et al., 2001). The situation is different in the air for aerosol particles. Firstly, in