4 ms·Why luckily? There's limited proof of any efficiency of masks.by skocznymroczny 5y agoWhy luckily? There's limited proof of any efficiency of masks.dalu 5y agoPlease don't spread disinformationadrianN 5y agoIs there solid data that shows no efficiency? Masks are fairly cheap, if they help even a little they're worthwhile.