Estimation of Required Monitoring Time for Obtaining Validation Data in Enclosed Spaces

Details

• Personal Author:
  Feigley CE ; Hussey JA ; Lee EG ; Slaven, James E.
• Description:
  Methods for estimating airborne contaminant concentrations at specific locations within enclosed spaces, such as mathematical models and computational fluid dynamics (CFD), often are validated against directly measured concentrations. However, concentration variation with time introduces uncertainty into the measured concentration. Failure to determine monitoring time requirements can lead to errors in quantifying representative concentrations, which are likely to be attributed to errors in the method being validated. In the current study, to obtain the representative concentrations at multiple locations with a direct reading instrument, we used the standard deviation ratio (SDR) method to determine the required minimum monitoring time within a specified precision limit. To demonstrate the use of the SDR approach in constructing precision confidence intervals, tracer gas concentrations at nine sampling locations in an experimental room were measured to obtain population parameters. Three flow rates of 0.9, 3.3 and 5.5 m3 min-1 were employed and contaminant concentrations were measured using a photoionization analyser. Monitoring time requirements varied substantially with location within the room and were strongly dependent upon the flow rate of air through the room. The proposed method would be very useful for industrial hygienists and indoor air researchers who sometimes need to obtain several hundred measured concentrations for validation purposes or to perform tests under repeatable conditions in enclosed spaces. This study also showed that the proposed method can be used to devise efficient indoor monitoring strategies. [Description provided by NIOSH]
• Subjects:
  Aerosols Air Pollutants, Occupational Confined Spaces Environmental Health Environmental Monitoring Occupational Health Particulate Matter Safety
• Keywords:
  Aerosol-particles Air-quality-measurement Air-sampling-techniques Airborne-particles Confined-spaces Indoor-environmental-quality Mathematical-models Measurement-equipment Monitoring-systems Statistical-analysis Statistical-quality-control

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• ISSN:
  1464-0325
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; OSHA Region 4 ; South Carolina ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  10
• Issue:
  11
• NIOSHTIC Number:
  nn:20034752
• Citation:
  J Environ Monit 2008 Oct; 10(11):1350-1356
• Contact Point Address:
  Eun Gyung Lee, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Exposure Assesment Branch, Health Effects Laboratory Division, 1095 Willowdale Road, Morgantown, WV 26505
• Email:
  dtq5@cdc.gov
• Federal Fiscal Year:
  2009
• Performing Organization:
  University of South Carolina at Columbia, Columbia, South Carolina
• Peer Reviewed:
  True
• Start Date:
  20010901
• Source Full Name:
  Journal of Environmental Monitoring
• End Date:
  20050831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:a09748f83e74905b484109362574f9562b935d12da5669704ca220b240994db84839e5b9c39322694d3fa9e090f930eed49a42e6b265da3920477006833de0dc
• Download URL:
  https://stacks.cdc.gov/view/cdc/186845/cdc_186845_DS1.pdf
• File Type:
  [PDF - 727.28 KB ]