It’s not just the pore size in the material. The always-present gaps between the mask and the face are where most of the leakage occurs. It is impossible to seal these gaps with a paper mask. It is extremely difficult to seal the gaps even with a professionally fitted N95 mask.
The pressure drop through the mask material causes a lot of air to leak around the mask through the mask/skin gaps.
Just look at the gaps around your nose, even with the metal nose-bridge band squeezed around your nose.
Watch how people wear the stupid things — they are always all over the place on the face with big air gaps present.
I spent the last 8 months in North Idaho. Idaho never went nuts over masking and largely left it to personal choice (except Wells Fargo Bank and a few other merchants). Almost nobody in North Idaho is wearing a mask.
I came back to the San Francisco Bay Area last Saturday and I’m shocked to still see 5% to 10% of people wearing the face diapers.
The common masks in a medical setting were only ever for shielding one’s face from spray or splash of bodily liquids and catching whatever of the same that might otherwise go in the opposite direction, by coughing or sneezing etc. No protection from airborne virions.
It’s easily 5-10% h343 in NH.
Higher in the more liberal areas.
You can basically tell a person’s political affiliation by their mask wearing.