Breathability + Filtration

What the numbers mean:

Due to our DIY test rigs, it is best to look at the particle filtration & breathability results in terms of relativity.

The closer the breathability number is to 0, the easier it is to breathe. The more negative it is, the harder it is to breathe. N95 measures at -31 and is our baseline.

Masks made of harder to breathe material can potentially force leaks around the mask.

Breathability appears to be generally additive so material breathability can be grossly summed up to estimate breathability for when materials are layered together.

Filtration becomes more consistent when layered.

Best DIY filter material:

If air filters like a 3M Filterete 1900 or Nordic Pure Air's merv 13 are safe to breathe through, they filter out the most. Since they are so breathable. They can be used as is or put between thin cotton and is still breathable.

Vacuum bags, without the paper, filters a lot and is breathable. However, they may not be quite breathable enough to be inserted as a filter.

Please make sure material does not include fiberglass.

You can request try to get a Material Safety Data Sheet from the manufacturer for the safety qualities of the material.

Breathability

Since we are only testing breathability at 20mm diameter, and breathability can be greatly increased by slight increase of surface area, we don't have a good sense how much more negative of a breathability gets unbreathable and can risk mask leakage.

Given that the KF94 is at -41, can breathability up to -41 be ok?