Are surgical masks better than cloth? Not if it's 2-layer cotton. A report by theSmithsonian’s Conservation Institute and the NIST (National Institute of Standards and Technology) stated that 2-layer 100% cotton masks have surprisingly higher filtration properties than surgical masks in real-world humid conditions, but polyester or poly-cotton masks perform less well. The cloth mask used in the Bangladeshi trial was a poly-cotton blend with only 37% filtration properties, much lower than other 2-layer cotton masks. Reports about the Bangladeshi study stating that surgical masks are better than cloth masks are misleading. Not all cloth masks are the same, and cotton masks are better than poly-cotton masks that were used in the Bangladeshi trial.
A recent Science Magazine report confirmed what SmitMask and scientists have observed from the beginning - that Covid is airborne. 1% mask leakage leads to 50% reduction in filtration efficiency. When masks are not worn tightly sealed, opening windows regularly is very important when wearing non-N95 masks.
