Abstract
As regards the ultraviolet germicidal lamp, study was made of the purifying action on the indoor air.
In a dining room for the general mass, an experiment was performed changing the conditions only for opening or closing windows without the alteration of ordinary warking conditions.
Even in the instance of keeping windows open, a considerable reduction in the number of colonies of falling bacteria in the room was recognized through the lighting of an ultraviolet lamp, but the lighting of lamp with the closure of windows produced a far more marked germicidal effectiveness han in the case of opened windows, the bacterial decrease rate being 67%.