Quantitative comparison of the autofluorescence of bacteria and polystyrene microspheres under violet wavelength excitation for verification of fluorescence-based bioaerosol detector results.

The autofluorescence intensity of bacteria and fungal spores was quantified by fluorescence microscopy in order to obtain the information for evaluating fluorescence-based bioaerosol detectors and was comparable to that of some types of polystyrene microspheres (PSMs). Although the intensity for microbes was distributed across a wide range over an order of magnitude in gray scale, it was in the intensity range of certain PSMs. Furthermore, some of those bacteria and PSMs were aerosolized in a test chamber and the fluorescence intensity was measured with a bioaerosol detector. Although there was a slight difference in the order of intensity from the results obtained by fluorescence microscopy, the fluorescence-based bioaerosol detector showed the intensity was in a comparable range.