Background
Respiratory protection devices are used to protect the wearers from inhaling particles
suspended in the air. Filtering face piece respirators are usually tested utilizing
nonbiologic particles, whereas their use often aims at reducing exposure to biologic
aerosols, including infectious agents such as viruses and bacteria.
Methods
The performance of 2 types of N95 half-mask, filtering face piece respirators and
2 types of surgical masks were determined. The collection efficiency of these respiratory
protection devices was investigated using MS2 virus (a nonharmful simulant of several
pathogens). The virions were detected in the particle size range of 10 to 80 nm.
Results
The results indicate that the penetration of virions through the National Institute
for Occupational Safety and Health (NIOSH)-certified N95 respirators can exceed an
expected level of 5%. As anticipated, the tested surgical masks showed a much higher
particle penetration because they are known to be less efficient than the N95 respirators.
The 2 surgical masks, which originated from the same manufacturer, showed tremendously
different penetration levels of the MS2 virions: 20.5% and 84.5%, respectively, at
an inhalation flow rate of 85 L/min.
Conclusion
The N95 filtering face piece respirators may not provide the expected protection level
against small virions. Some surgical masks may let a significant fraction of airborne
viruses penetrate through their filters, providing very low protection against aerosolized
infectious agents in the size range of 10 to 80 nm. It should be noted that the surgical
masks are primarily designed to protect the environment from the wearer, whereas the
respirators are supposed to protect the wearer from the environment.
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Article Info
Publication History
Published online: February 07, 2006
Cincinnati, Ohio, and Warsaw, PolandFootnotes
Supported in part by the Kosciuszko Foundation (American Center for Polish Culture).
Identification
Copyright
© 2006 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
