Exposure assessment by the measuring inward leak rate for airborne ambient particles into the mask

Abstract

BACKGROUND AND AIM: With the novel coronavirus outbreak (COVID-19), there has been increasing concern about the dust-proof performance of masks. In this study, we used a wearing mask fit tester (MT-05: SIBATA) to evaluate the amount of the fine airborne particles (size: 0.3 μm to 0.5 μm) penetrate the mask (leakage rate or penetration rate). METHODS: During the period September 2017, participants were recruited in the shopping mall in Yamanashi, Japan. They wear two types of masks we had prepared: a sanitary surgical mask (use cut 99% or more in the PFE test) and a cup-shaped mask (use an N 95 filter). Leakage rates were measured in normal breathing before and in motion (head side to side, talking) and normal breathing after the move. Data were analyzed using a linear mixed model. This study was approved by the Ethics Committee of the Faculty of medicine, University of Yamanashi (1710). RESULTS:We recruited 102 participants by the research coordinator and obtained their informed consent. The mean Difference for leakage rates of the surgical mask vs. the cup mask was 0.281 (95% CI 0.244 to 0.318, P 0.001), women vs. men was 0.225 (-0.411 to -0.040, P = 0.017). It showed a trend lower leakage rates of the cup mask and among women significantly in this study. Both masks showed a higher leakage rate during motion (Head side to side, Talking) but a lower leakage rate after motion, indicating that moving the face enhances the fit. CONCLUSIONS:The purpose of the mask is not achieved simply by wearing it, and if the type of the mask is not selected and handled correctly, it is impossible to prevent the suction of particles sufficiently. The effect is exhibited by simultaneously clearing the filter performance and the fitting property to the individual face. KEYWORDS: Air pollution, Exposures, Masks, Multi-pollutant, Microbes, COVID-19