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Collection of airborne spores by circular single-stage impactors with small jet-to-plate distance

Grinshpun, S.A., Mainelis, G., Trunov, M. G¨®rny, R. L., Sivasubramani, S.K. and Reponen, T.
2005
Journal of Aerosol Science, 36(5-6): 575-591

Grinshpun, S.A., Mainelis, G., Trunov, M. G¨®rny, R. L., Sivasubramani, S.K. and Reponen, T., (2005), "Collection of airborne spores by circular single-stage impactors with small jet-to-plate distance", Journal of Aerosol Science, 36(5-6): 575-591.
Abstract:
Most of the commonly used bioaerosol samplers are single-stage impactors that meet the conventional Marple's design criteria: their non-dimensional jet-to-plate distance, S/W, is greater than the established threshold (1.5 for rectangular nozzles and 1 for the circular ones). Recent studies have shown that these samplers underestimate the concentration of airborne fungal spores because their cut-off size is about View the MathML sourcem (Air-O-Cell and Burkard samplers) or greater while some fungal species produce spores of ca. 1.8-View the MathML sourcem in aerodynamic diameter. In this study, we evaluated the single-stage circular-jet impactors with very small jet-to-plate distances (S/Wdouble less-than sign1). The laboratory and field data obtained with test particles of different sizes and different origin (biological and non-biological) demonstrated the feasibility of these "incorrectly designed" impactors for the spore collection and total enumeration (viable + non-viable spores). A decrease in the jet-to-plate distance resulted in a critical decrease of the impactor's cut-off size (d50): from View the MathML sourcem to about View the MathML sourcem. This reduction of cut-off size makes such an impactor efficient for collecting spores of all fungal species (View the MathML sourcem) and even some bacterial species (View the MathML sourcem). Since the spore surface density across the circular deposit area was non-uniform, three sample reading procedures were evaluated: the entire area count, random partial count, and a partial count on a rectangular "diametric slice". The collection efficiency data suggested that a relatively small jet-to-plate distance is likely to result in excessive shear forces in the impaction zone, thus enhancing the spore deaggregation and bounce. The coefficient of inter-sample variation of the field samples, collected by commercially available impactors with S/W¡Ö0.099, did not exceed 50% for the total spore count. The highest variability was observed for Arthrospores, which were more aggregated than other types of fungi.

Keywords: Impactor; Bioaerosol; Collection efficiency; Jet-to-plate distance

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Author Information and Other Publications Notes
Grinshpun, S. A.
  1. Aerodynamic versus physical size of spores: measurement and implication for respiratory deposition
  2. Aerosol characteristics of airborne actinomycetes and fungi
  3. Bioaerosol collection by a new electrostatic precipitator
  4. Characteristics of airborne actinomycete spores
  5. Collection of airborne microorganisms by a new electrostatic precipitator
  6. Collection of bioaerosol particles by impaction: effect of fungal spore agglomeration and bounce
  7. Collection of fungal spores on air filters and spore reentrainment from filters into air
  8. Development and evaluation of aerosol generators for biological materials
  9. Effect of impact stress on microbial recovery on an agar surface
  10. Effect of relative humidity on the aerodynamic diameter and respiratory deposition of fungal spores
  11. Evaluation of a new personal sampler for enumerating airborne spores
  12. Field Testing of New Aerosol Sampling Method With a Porous Curved Surface as Inlet
  13. Fungal fragments as indoor air biocontaminants
  14. Fungal spore source strength tester: laboratory evaluation of a new concept
  15. Improved aerosol collection by combined impaction and centrifugal motion
  16. Inlet sampling efficiency of bioaerosol samplers
  17. Long-term sampling of airbome bacteria and fungi into a non-evaporating liquid
  18. Performance characteristics of the button personal inhalable aerosol sampler
  19. Performance of Air-O-Cell, Burkard, and Button samplers for total enumeration of airborne spores
  20. Release of lead-containing particles from a wall enclosure
  21. Release of Streptomyces albus propagules from contaminated surfaces
  22. Techniques for dispersion of microorganisms into air  
Mainelis, G.
  1. Bioaerosol collection by a new electrostatic precipitator
  2. Collection of airborne microorganisms by a new electrostatic precipitator
  3. Release of Streptomyces albus propagules from contaminated surfaces  
Trunov, M. G.
  1. Collection of bioaerosol particles by impaction: effect of fungal spore agglomeration and bounce
  2. Release of lead-containing particles from a wall enclosure  
Sivasubramani, R. L.
     
Reponen, T.
  1. Aerodynamic diameters and respiratory deposition estimates of viable fungal particles in mold problem dwellings
  2. Aerodynamic versus physical size of spores: measurement and implication for respiratory deposition
  3. Aerosol characteristics of airborne actinomycetes and fungi
  4. Bioaerosol collection by a new electrostatic precipitator
  5. Characteristics of airborne actinomycete spores
  6. Collection of airborne microorganisms by a new electrostatic precipitator
  7. Collection of bioaerosol particles by impaction: effect of fungal spore agglomeration and bounce
  8. Collection of fungal spores on air filters and spore reentrainment from filters into air
  9. Comparison of concentrations and size distributions of fungal spores in buildings with and without mould problems
  10. Control of exposure to airborne viable microorganisms during remediation of moldy buildings; report of three case studies
  11. Development and evaluation of aerosol generators for biological materials
  12. Effect of building frame and moisture damage on microbiological indoor air quality in school buildings
  13. Effect of indoor sources on fungal spore concentrations and size distributions
  14. Effect of relative humidity on the aerodynamic diameter and respiratory deposition of fungal spores
  15. Evaluation of a new personal sampler for enumerating airborne spores
  16. Everyday activities and variation of fungal spore concentrations in indoor air
  17. Field Testing of New Aerosol Sampling Method With a Porous Curved Surface as Inlet
  18. Fungal fragments as indoor air biocontaminants
  19. Fungal spore source strength tester: laboratory evaluation of a new concept
  20. Long-term sampling of airbome bacteria and fungi into a non-evaporating liquid
  21. Performance of Air-O-Cell, Burkard, and Button samplers for total enumeration of airborne spores
  22. Personal exposures and microenvironmental concentrations of particles and bioaerosols
  23. Release of Streptomyces albus propagules from contaminated surfaces
  24. Size distributions of airborne microbes in moisture-damaged and reference school buildings of two construction types
  25. Techniques for dispersion of microorganisms into air
  26. Total and culturable airborne bacteria and fungi in arid region flood-damaged residences
  27. Viable fungal spores as indoor aerosols  


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