Here is some interesting information regarding homemade mask materials:
https://www.maskfaq.com/test-results
Filti looks promising, and can be purchased here:
https://filti.com/product/filti-face-mask-material/
I am currently trying this. I use cotton masks with pockets and I cut the filti liners to fit, inserting two liners into each mask.
I cannot say how well it works, but it is breathable. It feels more like breathing through a n95 respirator than a cotton or surgical mask alone.
Other than that I cannot say how effective they are, just hoping the above study is accurate.
In India’s richest city, hospitals are overrun and doctors are collapsing
Thanks!