Was looking for info on how to use textile (or other natural material ) as a air filter. Ok it depends on how dense its woven,but nothing good found. As for a filter test i think it could be something as a frame with a 10 SF of the material and 2 inch water,the flow would be a measure for the pore size.The practical best pore size(s) for volcanic dust. pre and fine filter. maybe even useful as a pollen filter.