Masks efficiency?
Here are the numbers.
A virus particle is 0.125 microns.
An N95 mask only filters out particles 0.3 microns
Therefore every hole in a N95 mask lets in up to 3 virus particles.
Now a paper mask filters out particles up to 2.0 microns.
Therefore letting in 16 virus particles in every hole

Based on those figures I have constructed a mosquito proof mask.
I think you get the picture

image