(421a) Experimental Setup for Testing of Photocatalytic Decontamination Efficiency of Deposited Bacillus Atrophaeus Spores on UV-active Surface

An assembly of a chamber for generating bioaerosol is described here. Bacillus atrophaeus¹ spores were used as biological agent. The bioaerosol chamber was designed for testing different kinds of surfaces for example photocatalytic UV-active nanoparticle coated surface. Test materials were metal plates coated by two layers of paint and one layer of lacquer. Onto top of the lacquer TiO₂/Ag nanoparticles were generated using Liquid Flame Spray² method. Lacquered surfaces without nanoparticles and glass plates were used as reference. The bioaerosol was generated by Hudson RCI nebulizer. The particle size distribution of the produced aerosol was measured by Aerodynamic Particle Sizer, APS. The amount of CFU (colony forming unit) per litre air was determined by impinger. Also slit to agar collector was used to measure ACPLA (agent containing particles per litre air). Petri dishes were positioned at the bottom of the chamber to determine the bioaerosol distribution. The bioaerosol was according to the study evenly distributed throughout the chamber bottom. Contact samples were taken of 1/3 of the plates immediately after contamination of the test plates. 1/3 of the plates were exposed to UV-radiation and the rest were kept in dark several hours and tested afterwards. It was possible to generate bioaerosol onto the test surfaces and the tests showed the decontamination efficiency of the photocatalytic surfaces.

(1) Bacillus atrophaeus, strain number E-052737, Culture Collection, VTT, Finland

(2) J. Tikkanen, M. Eerola, V. Pitkänen, M. Rajala, Patent No. FI98832, 16.3., 1997.