Detection of Bioaerosols Using Multiwavelength UV Fluorescence Spectroscopy
Titel:
Detection of Bioaerosols Using Multiwavelength UV Fluorescence Spectroscopy
Auteur:
Cheng, Y. S.
Verschenen in:
Aerosol science and technology
Paginering:
Jaargang 30 (1999) nr. 2 pagina's 186-201
Jaar:
1999-02-01
Inhoud:
This article describes the development of an aerosol generation apparatus to investigate the fluorescence spectra of bioaerosols. The experimental system was set up in a Biosafety Level II Laboratory. The system included an aerosol generator, chamber, aerosol monitoring instrumentation, and laser-induced-fluorescence detection system. The aerosol generators, chamber, and monitors were housed in an enclosure with the exhaust vented through a double HEPA filtration system. A Hospitak nebulizer using aqueous suspensions generated aerosols of bacteria. Aerosols of pollens were generated using a small-scale dry powder generator. The aerosol chamber, with four windows for optical access, was designed with the aid of a computational fluid dynamics code to optimize the generation of aerosol beams with a well-defined geometry for reproducible fluorescence measurements. Aerosol concentrations and aerodynamic diameters in the chamber were determined using a filter, an impinger, a modified Andersen impactor, and an Aerodynamic Particle Sizer. Geometric size and particle shapes were determined using microscopy and imaging analysis. The well-characterized aerosol stream allowed reproducible fluorescence measurements to be made with the aerosol generation methods developed in this work. Fluorescence spectra of four bacteria, Escherichia coli, Staphylococcus aureus , Bacillus subtilis var niger , and Bacillus thuringiensis , were found to be very similar. Calibrations of the fluorescence instrumentation allowed cross sections of live cells, killed cells, and spores to be measured with an uncertainty of about 2 to 5.
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