Interesting. Is it that particles smaller than 0.3 microns have more dynamic and random motion? I mean, why is it that particles smaller than 0.3 microns are likely to be "stuck" where as at 0.3 microns they aren't?
I realized the original comment was about surgical masks.. I was commenting about the filtering properties of multi-layered polypropylene masks. I'm afraid its a bit beyond my Science / Engineering / Maths skills at the moment to try and explain it any better.. but maybe this link will help? https://www.tandfonline.com/doi/abs/10.1080/00022470.1980.10...