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Efficiency of N95 filtering facepiece respirators and surgical masks against airborne particles of viral size range: tests with human subjects.

Lee SA; Grinshpun SA; Reponen T
American Industrial Hygiene Conference and Exposition, May 21-26, 2005, Anaheim, California. Fairfax, VA: American Industrial Hygiene Association, 2005 May; :57
Airborne viruses have drawn the world's attention after the outbreaks of SARS (Severe Acute Respiratory Syndrome) occurred in Asia. Some studies have shown that corona virus might have caused SARS since it was isolated from patients' body fluids and respiratory secretions. To prevent people from the airborne SARS infection, N95 filtering facepiece respirators and surgical masks have been recommended by the Centers for Disease Control and Prevention and the World Health Organization. At the same time, no sufficient information is available on the protection characteristics of these devices against aerosol particles of the viral size range. We have recently developed a personal sampling system for measuring the protection provided by respirators against airborne dust and microorganisms ranging from 0.7 to 10 microm in aerodynamic diameter. In this study, we have modified the system so that it can be utilized to conduct performance tests with stimulant particles of the viral size range i.e., 0.02 to 0.3 microm. The experiments were carried out using this modified facility with six human subjects while the subjects were performing exercises following the OSHA fit testing protocol (29 CFR 1910.134). The results showed that there is no significant effect of human activity on the efficiency of these respirators against the viral simulants. The mean protection factors (34.5 +/- 20.6) of N95 filtering facepiece respirators were four to eight times higher than those of surgical masks (6.0 +/- 3.3). No particle size dependence of the protection factor provided by N95 filtering facepiece respirators and surgical masks was observed with-in the tested particle size range.
Respiratory protection; Respiratory protective equipment; Respirators; Airborne particles; Microorganisms; Aerosols; Aerosol particles; Viral diseases; Viral infections; Infection control; Infectious diseases
Publication Date
Document Type
Funding Amount
Funding Type
Fiscal Year
Identifying No.
Grant-Number-R01-OH-004085; Grant-Number-T42-CCT-510420
Priority Area
Research Tools and Approaches: Control Technology and Personal Protective Equipment
Source Name
American Industrial Hygiene Conference and Exposition, May 21-26, 2005, Anaheim, California
Performing Organization
University of Cincinnati
Page last reviewed: June 15, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division