I signed up to this website just to follow the coffee filter as facemask thread! I'm considering sewing some masks with a pocket for a filter in them. The best info I've found yet says that for masks, more fabric is better (pleated better than straight), which makes sense, biologically. Think pleated sheets in proteins? More surface area! Also found data that a tea towel (dishcloth) is close to as effective as a surgical mask. I think the idea is, capture as many particles as possible while still allowing air to flow through. A quick search for filter papers comes up with air furnace filters, vacuum filters, various filter papers for scientists, air filters for motors, tea bags, and coffee filters. I might try coffee filters inside a home-made mask, or maybe even folded (pleated) paper towels stuck in there between two sheets of fabric?
Also, to consider, improper use of these masks theoretically could INCREASE one's risk of contracting the disease. Imagine the virus gets stuck on the outside or filter of a mask, just like it is supposed to. Then the wearer handles mask and reuses the mask. Masks CATCH pathogens! Wearer handles mask and accidentally gets virus on INSIDE of mask. Wearer is toast. Caution needed. I recently read about a nurse contracting COVID-19 most likely from reusing a N-95 mask that she was instructed to leave in a bag outside rooms between patients, then reuse. Storing a mask in a bag and reusing it? Seems like a virus has a pretty good chance of going from outside of mask, to bag material, to inside of mask, to your mouth or nose. Sketchy.
