Impact of Environmental Factors on Efficacy of Upper-Room Air Ultraviolet Germicidal Irradiation of for Inactivating Airborne Mycobacteria

Details

• Personal Author:
  Hernandez M ; Kujundzic E ; Miller SL ; Moss G ; Peccia J ; Schafer, Millie P. ; Xu P
• Description:
  This study evaluated the efficacy of an upper-room air ultraviolet germicidal irradiation (UVGI) system for inactivating airborne bacteria, which irradiates the upper part of a room while minimizing radiation exposure to persons in the lower part of the room. A full-scale test room (87 m3), fitted with a UVGI system consisting of 9 louvered wall and ceiling fixtures (504 W all lamps operating) was operated at 24 and 34 C, between 25 and 90% relative humidity, and at three ventilation rates. Mycobacterium parafortuitum cells were aerosolized into the room such that their numbers and physiologic state were comparable both with and without the UVGI system operating. Airborne bacteria were collected in duplicate using liquid impingers and quantified with direct epifluorescent microscopy and standard culturing assay. Performance of the UVGI system degraded significantly when the relative humidity was increased from 50% to 75-90% RH, the horizontal UV fluence rate distribution was skewed to one side compared to being evenly dispersed, and the room air temperature was stratified from hot at the ceiling to cold at the floor. The inactivation rate increased linearly with effective UV fluence rate up to 5 W cm-2; an increase in the fluence rate above this level did not yield a proportional increase in inactivation rate. [Description provided by NIOSH]
• Subjects:
  Air Pollutants, Occupational Bacteria Dust Humidity Occupational Health Particulate Matter Radiation Safety Temperature Ultraviolet Rays Ventilation

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• Keywords:
  Air-temperature Airborne-particles Bacterial-dusts Bactericides Germicides Irradiation Radiation-exposure Temperature-effects Ultraviolet-radiation
• ISSN:
  0013-936X
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Colorado ; Ohio ; OSHA Region 5 ; OSHA Region 8
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DART - Division of Applied Research and Technology
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  39
• Issue:
  24
• NIOSHTIC Number:
  nn:20029233
• Citation:
  Environ Sci Technol 2005 Dec; 39(24):9656-9664
• Contact Point Address:
  The National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Public Health Services, U. S. Department of Health and Human Services, 4676 Columbia Parkway, MS R-3, Cincinnati, Ohio 45226-1099
• Federal Fiscal Year:
  2006
• Peer Reviewed:
  True
• Source Full Name:
  Environmental Science and Technology
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:e21025813fa8bc83f14c2111e9d92f939c2f7dcc8484d959f2fa29ed4138fe4dbba5aada587fdc29035245ee95208d5da44ab5525a7aeaf93d35c6fb75dd3ac4
• Download URL:
  https://stacks.cdc.gov/view/cdc/190266/cdc_190266_DS1.pdf
• File Type:
  [PDF - 247.15 KB ]