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Re-aerosolization of microorganisms from the filter media of health care respirators.

Qian-Y; Donnelly-J; Ulevicius-V; Willeke-K
American Industrial Hygiene Conference and Exposition, May 20-24, 1996, Washington, DC. Fairfax, VA: American Industrial Hygiene Association, 1996 May; :1
Health care respirators are used to protect health care workers and patents against airborne microorganisms such as Mycobacterium tuberculosis. While the respirator wearer inhales, microorganisms present in the air environment may deposit on the respirator's filter material These captured microorganisms may become a secondary contamination source under adverse conditions such as coughing or sneezing. The purpose of this study was to investigate the re-aerosolization of captured microorganisms from the filter media of health care respirators. Different filter media of health care respirators were cut into 40 mm disks in diameter and were tested as typical filtration velocities of 0.6 m/s and higher in the direction opposite to the loading flow rate. Also, a high velocity jet was used to re-aerosolize these microorganisms and inert spherical test particles from the filter media to see whether under extremely adverse condition a sizable fraction of the deposited organisms may be re-aerosolized. The measurement for particles loading and re-aerosolization were conducted with Aerosizer, a real-time particle size spectrometer. The results indicate that at air velocities below 1 m/s only a very small percentage of the microorganisms re-aerosolized from the filter media (less than 0.01%). The jet flow results In higher re-aerosolization, up to 0.5%. Re-aerosolization increases with increasing particle size. Based on the results obtained so far, it can be concluded that re-aerosolization of microorganisms appears to be a minor problem under normal breathing conditions. The further testing of a diversity of filter materials may modify this initial conclusion.
Health-care; Respirators; Airborne-particles; Microorganisms; Respiration; Filters; Filter-materials; Air-contamination; Respiratory-protection; Respiratory-protective-equipment; Measurement-equipment; Particulate-dust; Particulates
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American Industrial Hygiene Conference and Exposition, May 20-24, 1996, Washington, DC
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University of Cincinnati, Cincinnati, Ohio
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division