Effect of Fluorescent Illumination on Bacteria Supported on Glass Slides

The photocidal effect of exposing S. aureus BC12041 to UVA-rich fluorescent light is demonstrated. In UVA-exposure studies with appropriate controls, CFUs of S. aureus BC12041 are reduced by approximately two logarithms in a high humidity environment (~85%) and by one logarithm in moderate humidity (~50% RH) over a 30-min treatment period. In similar studies at the high humidity, no differential effect was observed between test and control studies with B. subtilis ATCC 6633. Thus, it appears that UVA-rich fluorescent lighting may be a useful side effect obtained when employing an UVA-activated photocatalyst for the degradation of volatile organic compounds (VOCs) in indoor air.