Use of in-duct UVC lamps to inactivate airborne environmental bacteria and fungi

Germicidal UV (UVC) lamps have a long history of use for inactivation of microbial aerosols. The majority of the literature has considered control of infectious diseases, such as tuberculosis (TB) in medical facilities. Emphasis has recently been on ventilation duct use of UVC. Under these conditions, infections agents are usually of less concern than environmental organisms. Much less information is available regarding common environmental organisms. The present work reports the ability of UVC lamps to inactivate 7 representative microbial aerosols in ventilation duct conditions. Substantial inactivation of airborne environmental fungi was accomplished with UVC dose levels readily achievable using multiple lamps. The vegetative bacteria tested were relatively easy to inactivate, while the bacterial spores tested displayed an intermediate response. Fungal spores were difficult to inactivate.