(CBC)Blue three-ply surgical-type masksOne of the two-ply, high thread count cotton masks Marketplace tested. The three-layer cotton mask Marketplace tested did not perform well, but the two-layer cotton mask did. One of the three-ply cotton masks Marketplace tested. Masks made with 600 and 680 thread count cotton had filtration efficiencies almost twice that of the other cotton masks tested. A two-layer, 100 per cent rayon mask was also among the worst performing masks Marketplace tested for filtration efficiency.

Source: CBC News November 13, 2020 09:00 UTC