Not exactly true. https://www.sciencemag.org/news/2020/04/you-may-be-able-spread-coronavirus-just-breathing-new-report-finds
On Sat, Apr 4, 2020 at 7:38 PM <mix...@bigpond.com> wrote: > In reply to Terry Blanton's message of Sat, 4 Apr 2020 18:35:31 -0400: > Hi, > [snip] > >I found an old Hoover HEPA vacuum bag and thought to make a mask. Then I > >Googled the idea. Nothing new under the sun. HEPA spec is 300 nm but > test > >show them effective down to 50 nm (depends on the rating). SARS-CoV-2 is > >125 nm. > > I think the size of the virus is irrelevant. The mask doesn't really have > to stop individual virus particles, it only > has to stop the moisture droplets that carry them. Droplets are thousands > of times larger than the virus. > A normal handkerchief/silk scarf should do fine provided that there are no > spaces around edge where droplets can bypass > the filter. > Regards, > > > Robin van Spaandonk > > local asymmetry = temporary success > >
