Continuous bioaerosol monitoring using UV excitation fluorescence

We describe an instrument developed to monitor the biological fraction of ambient aerosol. This device simultaneously sizes individual particles in an air stream, and measures their total fluorescence following excitation at 266 nm. Recent results of single blind outdoor tests carried out in Alberta, Canada are described. In these, aerosols were generated containing four different types of biological material: ova albumin, MS-2 phage, Erwinia herbicola vegetative cells and Bacillus subtilis spores. Results indicate a probability of detection of 87% was achieved for target aerosol concentrations as low as a few (1-5) P particles/liter. Absolute quantitative detection efficiencies for individual bioaerosols were at least 70%. During the tests, nonbiological aerosols were also released and found not to generate any significant fluorescent signals.