They compare a non-woven surgical mask and a handkerchief close-up. There is something right?Christophe wrote:It turns on the RS ... not checked the scale but it seems plausible (I think the virus is smaller still) ... except that it is wrong since the virus does not fly alone: it is contained in particles of liquid or fine particles ... much larger!
See table 3 page 11 https://apps.who.int/iris/bitstream/han ... .4-fre.pdf