The development of a pulsed UV-light air disinfection system and its application in university lecture theatres

Indoor air quality is an increasingly important issue in a wide variety of industrial, domestic and social settings, the most notable example being hospitals and healthcare facilities. The present study is concerned with the application of pulsed UV-rich light as an effective means of air disinfection. For this, a system was developed which involved the passing of volumes of air through a path of pulsed UV-rich light. The treated samples were then collected using an SAS Super-180 air sampler and the effects of this pulsed light on airborne bacterial populations were then investigated. Also, in an attempt to establish the extent of airborne bacterial contamination which can occur in specific situations, the microbiological air quality of university lecture theatres was monitored. The results obtained demonstrate a significant increase in airborne bacterial populations due to the presence of large student congregations. In addition, the application of UV-rich pulsed light was shown to be effective in reducing the levels of airborne bacteria within samples of air taken from the lecture theatres. Furthermore, treatment was found to be capable of eliminating the majority of the Staphylococcus spp. found in the air, and this is desirable since these bacteria are opportunistic pathogens compared to the saprophytic Micrococcus spp., some of which survived treatment.