Resumen
Wearing face masks is essential for reducing infection during the COVID-19 pandemic. However, ordinary surgical face masks can provide only moderate protection. The N95 face masks should provide sufficient protection but may impose complaints about breathing difficulty or even impair respiratory health. This investigation proposed a novel face mask modified from the surgical face mask to improve both protection and comfort. The filter material of the surgical face mask was covered and sealed on a cardboard support frame but with openings for air permeating through. The modified face masks were worn by a test subject for measuring the air contents inside the face masks. The protection performance was evaluated by the overall PM1 filtration efficiency. The concentrations of CO2, O2, N2, and water vapor were adopted to evaluate the breathing comfort. The performance of the proposed face mask was compared with the market-available surgical and N95 face masks. In addition, CFD modeling was adopted to investigate the dynamic air exchange of the face mask with respiration and the surrounding air. Impacts of the air sampling tube positions on the measurement results were also examined. The results revealed that the overall PM1 filtration efficiency of the modified face mask could reach 96.2%, which was much higher than that of the surgical face mask and only slightly lower than the N95 face mask. As compared with the N95 face mask, the modified mask reduced the respiratory flow resistance and the concentrations of CO2 and water vapor and thus increased the O2 content and breathing comfort.