Turns out the heavy duty surgical mask works really well
and the others but do help some and SOME is enough if that’s all you’ve got.
The Southern Research Institute, Birmingham, Alabama did a study of facemasks using
a regular squarish layered drugstore mask,
a round one that looks a bit like a coffee filter
and the N95 surgical version.
The N95 worked 95% and the others 35%. Big difference.
But– wait a minute. Ask yourself some obvious questions.
Do they really know everything about this?
Would you rather get a small dose or a full dose of poison?
If you have allergies that make being sick worse, would you rather also
skip the pollen that causes allergies using a bandana? Of course you would!
This study involved dust storm conditions and aeresol spray so the actual environments are not daily life on the street or subway. But they did create harsh wind and spray to get these findings.
DON’T RISK IT! Make a mask if you have to. Wear a mask.
And think about it. double thickness, close, tight edges are better.
Figure 5 is the good one.