While fitted N95 masks allowed zero droplets to pass through, the three-layered surgical masks too performed very well with 0-10% droplet transmission. N95 masks with exhalation valve fared poorly. Double-layered cotton masks were better that single-layered ones. Finally, the efficiency of N95, surgical masks and 12 other masks made of different materials to reduce droplet […]

via Two-layered polypropylene mask doubly better than a single-layered cotton mask, study finds — Science Chronicle