Variation in the fitted filtration efficiency of disposable face masks by sex

BACKGROUND & OBJECTIVE: Disposable face masks are a primary protective measure against adverse health effects from infectious and toxic aerosols. While fit of high-efficiency respirators is regulated in occupational settings, relatively little is known about the fitted filtration efficiencies (FFE) of ear loop style face masks worn by the public. METHODS: FFE of four commonly worn disposable face masks (N95 respirator, KN95, surgical, KF94) was measured in healthy adults (N=100; 50% female; mean age 32.3 ± 9.2 years; mean BMI 25.5 ± 3.4) using the OSHA Quantitative Fit Test. Ear loop masks were also tested in a clip-modified condition using a plastic clip to fasten loops behind the head. RESULTS: Sex was a major determinant of FFE for KN95, surgical, and KF94 masks; males averaged 11% higher baseline FFE than females. A simple ear loop clip modification improved average FFE substantially for females but only modestly for males (average increase: females +20%, males +6%). IMPACT: The efficacy of disposable face masks depends on material efficiency and fit. Sex strongly influences baseline FFE for ear loop masks, and an ear loop clip can substantially improve FFE for females with minor changes for males, informing public health use of masks against airborne contaminants.

Edward R. Pennington, Jacob S. Griffin, E. Melissa McInroe, William Steinhardt, Hao Chen, James M. Samet, Steven E. Prince