Study of a new photocatalytic air cleaner applied to the management of the microbiologicalindoor air quality

The objective of this research consists of studying the effectiveness of devices used in the microbiological purification of the air. This specifically involves the inactivationof biological aerosols in an air handling unit. The study of a first device working on the principle of photocatalysis has been carried out. This system, called NEO developed by the CIAT Company (patent WO 2004/081458), involves the combination of filtration on an adsorbent and heterogeneous photocatalysis.The air cleaning device in question is installed in a test box located in a wind tunnel called ONE-PASS. This test facility is composed of an intake air fan and an exhaust air fan, in order to regulate the test box to maintain a slightly negative pressure, which prevents any exterior leakage. A HEPA filtration unit is installed upstream to remove any particles from the supplied air and another HEPA filtration unit is present downstream to avoid any pollution in the exhaust air.The ONE-PASS is characterized in terms of the homogeneity of velocity profiles and particulate profiles.The aerosolisation of the bacteria Staphylococcus Epidermidis used for the tests is controlled. The flow of bacteria is stable and its concentration is known. Three main criteria of the purification rate are studied to determinethe level of effectiveness: concentrations of total flora, cultivable bacteria and particle count. A purificationrate superior to 98 % was found for the NEO system in the ONE-PASS platform for the cultivable bacteria.