Real-time measurement of bacterial aerosols with the UVAPS: performance evaluation

The Ultraviolet Aerodynamic Particle Sizer (UVAPS, Model 3312, TSI Inc., St. Paul, MN) spectrometer is the only commercially available aerosol counter for real-time monitoring of viable bioaerosols. Though the feasibility of this technique to monitor bioaerosols has been previously demonstrated by the instrument designers in a number of studies, the collection of meaningful data and their correct interpretation are still not possible without a thorough understanding of its capabilities and limitations. This paper presents the results of the first independent study aimed towards evaluating selectivity, sensitivity, counting efficiency, and the detection limits of the UVAPS. The study has demonstrated limitations in the capability of the instrument to measure bacterial spores that is explained by biochemical composition of the spores, which contain only minute amounts of the specific fluorophores that appeared to be below the instrument sensitivity level. The results were also indicative of strong sensitivity of the UVAPS to the physiological state of bacteria. Counting efficiency of the fluorescent particles was shown to depend on particle concentration with the upper limit of detection of the UVAPS around 6 x 107 particles/ m3.

[1]  S. C. Hill,et al.  Single-shot fluorescence spectra of individual micrometer-sized bioaerosols illuminated by a 351- or a 266-nm ultraviolet laser. , 1999, Optics letters.

[2]  Mark Seaver,et al.  Size and Fluorescence Measurements for Field Detection of Biological Aerosols , 1999 .

[3]  Susanne V. Hering,et al.  Air Sampling Instruments for Evaluation of Atmospheric Contaminants , 1989 .

[4]  A E Humphrey,et al.  Monitoring Cell Concentration and Activity by Multiple Excitation Fluorometry , 1991, Biotechnology progress.

[5]  R. Losick,et al.  Bacillus Subtilis and Other Gram-Positive Bacteria: Biochemistry, Physiology, and Molecular Genetics , 1993 .

[6]  J P Reilly,et al.  Fingerprint matching of E. coli strains with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of whole cells using a modified correlation approach. , 1998, Rapid communications in mass spectrometry : RCM.

[7]  W. Whitten,et al.  Real-time detection of individual airborne bacteria , 1997 .

[8]  J. Ho,et al.  Design of an instrument for real-time detection of bioaerosols using simultaneous measurement of particle aerodynamic size and intrinsic fluorescence. , 1997, Journal of aerosol science.

[9]  J. Errington,et al.  Bacillus subtilis sporulation: regulation of gene expression and control of morphogenesis. , 1993, Microbiological reviews.

[10]  S. C. Hill,et al.  Aerosol-fluorescence spectrum analyzer: real-time measurement of emission spectra of airborne biological particles. , 1995, Applied optics.

[11]  S. C. Hill,et al.  Conditional-firing aerosol-fluorescence spectrum analyzer for individual airborne particles with pulsed 266-nm laser excitation. , 1996, Optics letters.

[12]  Sidney N. Thornton,et al.  Field‐portable, automated pyrolysis‐GC/IMS system for rapid biomarker detection in aerosols: A feasibility study , 1997 .

[13]  K Willeke,et al.  Effect of impact stress on microbial recovery on an agar surface , 1995, Applied and environmental microbiology.

[14]  J Burt,et al.  Health symptoms and the work environment in four nonproblem United States office buildings. , 1995, Scandinavian journal of work, environment & health.

[15]  P. Hairston,et al.  Differences in Detected Fluorescence Among Several Bacterial Species Measured with a Direct-Reading Particle Sizer and Fluorescence Detector , 2000 .

[16]  Richard K. Chang,et al.  Aerosol Fluorescence Spectrum Analyzer for Rapid Measurement of Single Micrometer-Sized Airborne Biological Particles , 1998 .

[17]  Pyrolysis—Gas Chromatography—Mass Spectrometry: Detection of Biological Warfare Agents , 1993 .

[18]  J. Wimpenny,et al.  Levels of Nicotinamide Adenine Dinucleotide and Reduced Nicotinamide Adenine Dinucleotide in Facultative Bacteria and the Effect of Oxygen , 1972, Journal of bacteriology.

[19]  E. Faragher,et al.  An investigation of the relationship between microbial and particulate indoor air pollution and the sick building syndrome. , 1992, Respiratory medicine.

[20]  Yung-sung Cheng,et al.  Detection of bioaerosols using multiwavelength UV fluorescence spectroscopy , 1999 .

[21]  Sidney N. Thornton,et al.  Detection of the picolinic acid biomarker in Bacillus spores using a potentially field‐portable pyrolysis—gas chromatography—ion mobility spectrometry system , 1996 .

[22]  F. F. Cinkotai,et al.  Air Sampling Instruments for Evaluation of Atmospheric Contaminants , 1973 .

[23]  R. E. Buchanan,et al.  Bergey's Manual of Determinative Bacteriology. , 1975 .

[24]  S. C. Hill,et al.  Conditional-sampling spectrograph detection system for fluorescence measurements of individual airborne biological particles. , 1996, Applied optics.

[25]  K. R. May.  The collison nebulizer: Description, performance and application , 1973 .

[26]  P. Ross,et al.  Detection of pathogenic and non-pathogenic bacteria by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. , 1996, Rapid communications in mass spectrometry : RCM.

[27]  T. Hadfield,et al.  A rapid approach for the detection of dipicolinic acid in bacterial spores using pyrolysis/mass spectrometry. , 1996, Rapid communications in mass spectrometry : RCM.

[28]  M. L. Laucks,et al.  Aerosol Technology Properties, Behavior, and Measurement of Airborne Particles , 2000 .

[29]  John G. Bruno,et al.  Fluorescence Particle Counter for Detecting Airborne Bacteria and Other Biological Particles , 1995 .

[30]  J. Ho,et al.  Measurement of biological aerosol with a fluorescent aerodynamic particle sizer (FLAPS): correlation of optical data with biological data , 1999 .