Our group just published a paper that describes our study of three hospital rooms in which ultraviolet germicidal irradiation (UVGI) systems were installed.

As part of their infection control strategy, hospitals use upper-room ultraviolet germicidal irradiation (UVGI) systems to inactivate airborne infectious agents. A computational fluid dynamics model was developed and applied to evaluate the design of the three hospital rooms, a patient and exam room with upper-room systems, and a patient room with an exhaust duct system. One of the UVGI systems was not very effective, due to efficient ventilation design. The other two configurations were effective at inactivating airborne mycobacteria. The most effective application was the one for which the room air exchange rate was very low.

Miller et al. 2013 Photochemistry and Photobiology, in press