Figure 2.

Filter performance of respirator material before and after heat sterilization at 121°C for 15 min. The absence of coloured bars means that the efficiency score was below 90%. KN95-1 and KN95-2 respirators were not tested following sterilization due to underperformance before sterilization based on pre-set criteria; as such, post-sterilization filter performance of these respirators is not included in the figure. Dark blue bars, 0.3 μm before sterilization; orange bars, 0.5 μm before sterilization; grey bars, 1 μm before sterilization; yellow bars, 0.3 μm after sterilization; light blue bars, 0.5 μm after sterilization; green bars, 1 μm after sterilization.