The International Society for Respiratory Protection

pdf Vol. 25. No. 3. 2008 pp. 1 - 8 Vojtko (open access)

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Effect on Breathing Resistance of a Surgical Mask Worn over a N95 Filtering Facepiece Respirator Mark R. Vojtko, Marc R. Roberge, Richard J. Vojtko, Raymond J. Roberge, and Douglas P. Landsittel Concerns over potential shortages of filtering facepiece respirators in the face of a pandemic influenza have prompted suggestions that the use of a surgical mask as an outer barrier might prolong the useful life of the respirator, but the effect on breathing resistance of this tandem respiratory protection has not been scientifically evaluated. Utilizing pressure transducers coupled to a breathing mannequin programmed at low-to-moderate and moderate-to-high breathing volumes, the current study measured baseline inspiratory and expiratory pressures of N95 filtering facepiece respirators before and after placement of a surgical mask over the respirator. The use of a surgical mask concurrently with a N95 filtering facepiece respirator results in a statistically significant increase in breathing resistance over that of the respirator alone. Keywords: N95 filtering facepiece respirator, surgical mask, breathing resistance