A new photoreactor geometry has been designed to treat high flow rate air contaminated with airborne Legionella pneumophila bacteria by exclusive UV-A photocatalysis. A specific tangential reactor geometry with periodical illumination allowed high efficiencies for strongly contaminated air streams to be obtained, whereas its self-driven property strongly decreased the charge loss phenomena, crucial for targeting high flow rate air treatment applications. This type of photoreactor has been used as the basis for designing and commercializing photocatalytic decontamination devices for applications in the field of air treatment technology. (C) 2007 Elsevier B.V. All rights reserved.