American Journal of Infection Control
“…Two types of N95 half-mask respirators and 2 types of surgical masks were challenged with aerosolized MS2 virus. The experiments were carried out follow- ing a manikin-based protocol. The results indicate that N95-certified respirators may not necessarily pro- vide a proper protection against virus, which is consid- erably smaller than the accepted most penetrating particle size of 300 nm used in the certification tests. Thus, the protection against the airborne viral agents provided by some N95 respirators may fall below 95%, especially at higher inhalation flow rates. The efficiency of the surgical masks is much lower than that of the N95 respirators so that the MS2 virions pen- etrate readily through the surgical masks. The perfor- mance tests conducted with surgical masks challenged with latex spheres of ;300 nm or bacterial particles may underestimate the penetration of nanosize virions.”