The Orientation-Averaged Aspiration Efficiency of IOM-Like Personal Aerosol Samplers Mounted on Bluff Bodies

Details

• Personal Author:
  Paik SY ; Vincent JH
• Description:
  This paper describes two sets of experiments that were intended to characterize the orientation-averaged aspiration efficiencies of IOM samplers mounted on rotating bluff bodies. IOM samplers were mounted on simplified, three-dimensional rectangular bluff bodies that were rotated horizontally at a constant rate. Orientation-averaged aspiration efficiencies (A360) were measured as a function of Stokes' number (St), velocity ratio (R) and dimension ratio (r). Aspiration efficiency (A) is the efficiency with which particles are transported from the ambient air into the body of a sampler, and A360 is A averaged over all orientations to the wind. St is a dimensionless variable that represents particle inertia, R is the ratio of the air velocity in the freestream and that at the plane of the sampler's entry orifice, and r is the ratio of the sampler's orifice diameter and the bluff body's width. The first set of experiments were instrumental in establishing a hierarchy of effects on orientation-averaged A. It was clear that compared to r, St had a much larger influence on A. It was also clear, however, that the effects of St were overpowered by the effects of R in many cases. As concluded in previous studies, R and St were considered the most important factors in determining A, even for A360. The second set of experiments investigated A360 of IOM samplers for a much wider range of r than examined in previous research. Two important observations were made from the experimental results. One was that the A360 of IOM samplers, as a function of St, did not change for an r-range of 0.066-0.4. This meant that an IOM sampler mounted on a near life-size mannequin would measure the same aerosol concentration as one not mounted on anything. The second observation was that the aspiration efficiency curve of the IOM sampler was close to the inhalability curve. This gave further evidence that the bluff body did not play a major role in influencing A360, as the IOM samplers, in these experiments, were either mounted on miniature bluff bodies or on nothing at all. These observations all suggest that it is quite possible to design and test personal samplers with desired sampling characteristics using protocols that do not require full-size mannequins, which greatly simplifies the development of new samplers. [Description provided by NIOSH]
• Subjects:
  Health Personnel Occupational Health Respiratory Function Tests Respiratory Tract Diseases Safety
• Keywords:
  Aspiration Efficiency Author Keywords: Aerosol Sampling Bluff Body Health-care-personnel Inhalable Sampling Instrumentation IOM Sampler Lung-mechanics Mannequin Measurement-methods Obstructive-lung-disorders Orientation Averaging Particle Size-selective Criteria Physiological-tests Pulmonary-physiology Respiratory-function-tests Respiratory-system-disorders Restrictive-lung-disorders Stokes' Number Wind Tunnel

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• ISSN:
  0003-4878
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Michigan ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  3-11
• Volume:
  48
• Issue:
  1
• NIOSHTIC Number:
  nn:20029311
• Citation:
  Ann Occup Hyg 2004 Jan; 48(1):3-11
• Contact Point Address:
  James H. Vincent, Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109-2029
• Federal Fiscal Year:
  2004
• Performing Organization:
  University of Michigan, Ann Arbor, MI 48109 USA
• Peer Reviewed:
  True
• Start Date:
  19980930
• Source Full Name:
  Annals of Occupational Hygiene
• End Date:
  20020929
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:1e353cbc3edc3883d5eb5cc534d67f704591ce13fa507f172bea8b1b5bf33c79b906b08d98924757b1e3a91e4820c7bd4f4cbcc67799651c9af7f1447c1f5dcb
• Download URL:
  https://stacks.cdc.gov/view/cdc/190330/cdc_190330_DS1.pdf
• File Type:
  [PDF - 206.63 KB ]