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Effect of ultraviolet germicidal lamps on airborne microorganisms in an outpatient waiting room.

Macher JM; Alevantis LE; Chang L; Liu S
Appl Occup Environ Hyg 1992 Aug; 7(8):505-513
Air samples were collected in an occupied 90 cubic meter room equipped with four 15 watt wall mounted germicidal lamps. The room was used as the waiting room of an outpatient clinic in a hospital. Occupation exposure to 245 nanometer radiation was measured in the room when the lamps were in operation. A positive association was noted between the number of people present in the room and the indoor concentration of airborne bacteria. This positive association was also noted with the concentration of bacteria in the ventilation supply air and the relative humidity. A negative association was noted between the operation of the germicidal lamps and the number of open windows. The lamps, when used regularly, appeared to reduce culturable airborne bacteria by 14 to 19%. This was equivalent to between 1.5 and two air changes per hour. Germicidal lamp use in a typical hospital waiting room did not affect the concentrations of gram positive, rod shaped bacteria. For the fungi that were isolated in this study, the germicidal lamps had a small but not statistically significant effect. The ultraviolet radiation levels exceeded the 8 hour exposure limit at locations above 1 meter from the floor. Patients and staff members usually spent less than 1 hour in the room.
NIOSH-Publication; NIOSH-Contract; Infection-control; Control-technology; Infectious-diseases; Health-care-personnel; Ultraviolet-radiation; Air-contamination; Microorganisms
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Applied Occupational and Environmental Hygiene
Page last reviewed: September 22, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division