Results: A surgical mask consisting of filter material performed better than did a surgical mask consisting only of a shell with a coarse pore structure. The latter passed 80% of submicrometer-sized aerosols with little flow dependency, whereas the penetration of submicrometer-sized aerosols through the mask made of filter material ranged from 25% at a flow rate of 5 L/min to 70% at 100 L/min.
Conclusions: The mask that has the highest collection efficiency is not necessarily the best mask from the perspective of the filter-quality factor, which considers not only the capture efficiency but also the air resistance. Although surgical mask media may be adequate to remove bacteria exhaled or expelled by health care workers, they may not be sufficient to remove the submicrometer-size aerosols containing pathogens to which these health care workers are potentially exposed.
