https://www.cidrap.umn.edu/news-perspective/2020/04/commentary-masks-all-covid-19-not-based-sound-data
Know a little about water treatment. 2 feet of filter media will take out algae, bacteria, fungal spores, Protozoa. After the filters you hit it with chloramine to kill virus.
No- cotton masks as they say down on the farm are worthless as ‘tits on a boar hog’