Performance Characteristics of the Aerosol Collectors of the Autonomous Pathogen Detection System (APDS)

This research analyzes the physical performance characteristics of the aerosol collectors of the autonomous pathogen detection system (APDS) that was recently developed by the Lawrence Livermore National Laboratory. The APDS is capable of continuous and fully autonomous monitoring for multiple airborne threat organisms and can be used as part of a monitoring network for urban areas and major public gatherings. The system has already been successfully tested with airborne Bacillus anthracis and Yersinia pestis biowarfare agents. The APDS aerosol collection system consists of a PM-style cap to remove large particles and a low-pressure drop virtual impactor preconcentrator positioned in front of a wetted-wall cyclone. The aerosol collectors operate at flow rates as high as 3750 l/min and collect airborne particles into 4 ml of liquid for subsequent detection. In our tests we determined the overall collection efficiency of the system by measuring the difference between inlet and outlet particle concentrations. The tests were performed with polydisperse oleic acid and monodisperse polystyrene latex (PSL) particles (0.6–3.1 µ m), and for three values of the major air flow rates in the virtual impactor (1760, 2530, and 3300 l/min), two values of the product, or cyclone, flow rates (375 and 450 l/min), and two different volumes of collection liquid (4 and 6 ml). We found that the cutoff size (d50 ) of the entire collection system varied from 1.5 to 2.0 µ m when collecting PSL particles, with 3.1 µ m PSL particles being collected with efficiency of approximately 85%. When collecting oleic acid particles the d50 of the entire system varied from 1.1 to 1.6 µ m. The concentration rates of the aerosol collection system were found to increase with increasing overall collection flow rate and approached one million per minute at the highest tested flowrates. Such high concentrating rates and high air sample volumes make the APDS collection system highly suitable for detecting low concentrations of airborne pathogens.

[1]  M G Apte,et al.  Indoor air quality, ventilation and health symptoms in schools: an analysis of existing information. , 2003, Indoor air.

[2]  H. Parkes,et al.  Personal monitoring of exposure to genetically modified microorganisms in bioaerosols : rapid and sensitive detection using PCR , 1997 .

[3]  Fred P. Milanovich,et al.  Development of an Autonomous Pathogen Detection System , 2000 .

[4]  V. Marple,et al.  A High-Performance Aerosol Concentrator for Biological Agent Detection , 2002 .

[5]  A. Bennett,et al.  Enzyme-linked immunosorbent assay for the detection of airborne microorganisms used in biotechnology , 1997 .

[6]  I. Agranovski,et al.  Collection of Airborne Microorganisms into Liquid by Bubbling through Porous Medium , 2002 .

[7]  James T. Staley,et al.  Bergey's Manual of Determinative Bacteriology , 1939 .

[8]  John Bartlett.  Bioaerosols Handbook , 1996 .

[9]  Jonathan Thornburg,et al.  Counting Efficiency of the Api Aerosizer , 1999 .

[10]  Claire E Lenehan,et al.  Sequential injection analysis. , 2002, The Analyst.

[11]  A. zur Nieden,et al.  Effects of bioaerosol polluted outdoor air on airways of residents: a cross sectional study , 2003, Occupational and environmental medicine.

[12]  Stephen W. Farrow,et al.  Autonomous detection of aerosolized biological agents by multiplexed immunoassay with polymerase chain reaction confirmation. , 2005, Analytical chemistry.

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

[14]  Steve B. Brown,et al.  Autonomous detection of aerosolized Bacillus anthracis and Yersinia pestis. , 2003, Analytical chemistry.

[15]  S. T. Cowan.  Bergey's Manual of Determinative Bacteriology , 1948, Nature.

[16]  S. Reynolds,et al.  Dose-response relationships between occupational aerosol exposures and cross-shift declines of lung function in poultry workers: recommendations for exposure limits. , 2000, Journal of occupational and environmental medicine.

[17]  R. Kennedy,et al.  A New Method To Monitor Airborne Inoculum of the Fungal Plant Pathogens Mycosphaerella brassicicola andBotrytis cinerea , 2000, Applied and Environmental Microbiology.

[18]  T. Reponen,et al.  Collection of Bioaerosol Particles by Impaction: Effect of Fungal Spore Agglomeration and Bounce , 2001 .

[19]  E. Henningson,et al.  Evaluation of microbiological aerosol samplers: a review , 1994 .

[20]  H. N. Phan,et al.  Aerosol-to-Hydrosol Transfer Stages for Use in Bioaerosol Sampling , 2004 .

[21]  Benjamin Y. H. Liu,et al.  High-volume Impactor for Sampling Fine and Coarse Particles , 1990 .

[22]  G. Stelma,et al.  Effect of Impaction, Bounce and Reaerosolization on the Collection Efficiency of Impingers , 1997 .

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

[24]  T. Reponen,et al.  Limitations of monoclonal antibodies for monitoring of fungal aerosols using Penicillium brevicompactum as a model fungus. , 2003, Journal of immunological methods.

[25]  Steve B. Brown,et al.  Development of an automated sample preparation module for environmental monitoring of biowarfare agents. , 2004, Analytical chemistry.