Fluid physics says otherwise "Thirdly, we show that even simple mouth-and-nose covers made of good filter material cannot reliably protect against droplet infe

Fluid physics says otherwise "Thirdly, we show that even simple mouth-and-nose covers made of good filter material cannot reliably protect against droplet infection in contaminated ambient air, since most of the air flows through gaps at the edge of the masks. Only a close-fitting, particle-filtering respirator without an outlet valve offers good self-protection and protection against droplet infection" https://www.researchgate.net/publication/342693523_Fundamental_protective_mechanisms_of_face_masks_against_droplet_infections https://www.researchgate.net/publication/342693523_Fundament... There's rather too much "magic of the mask" conclusions being drawn without considering other factors. Nor is there consideration of the other issue. If you catch a disease while the mask is off, then when you put the mask back on you're breathing your own shedding back into different parts of your respiratory tract. Similarly, it's been shown that surgical masks don't do that much even in surgical settings: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4480558/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4480558/