This research is from 2013: Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic? Link to PDF: https://www.researchgate.net/pro

This research is from 2013: Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic? Link to PDF: https://www.researchgate.net/profile/Katy-Anne_Thompson2/publication/258525804_Testing_the_Efficacy_of_Homemade_Masks_Would_They_Protect_in_an_Influenza_Pandemic/links/53fefd8f0cf21edafd154e85/Testing-the-Efficacy-of-Homemade-Masks-Would-They-Protect-in-an-Influenza-Pandemic.pdf https://www.researchgate.net/profile/Katy-Anne_Thompson2/pub... Summary: > Several household materials were evaluated for the capacity to block bacterial and viral aerosols. Twenty-one healthy volunteers made their own face masks from cotton t-shirts; the masks were then tested for fit. The number of microorganisms isolated from coughs of healthy volunteers wearing their homemade mask, a surgical mask, or no mask was compared using several air-sampling techniques. > Our findings suggest that a homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection. Interestingly, tea towels (dish cloths) showed a higher level of filteration than t-shirts in this study. Edit: here is a more recent review of the scientifc literature on cloth masks from the Royal Society in the UK. This is a pre-print - link is to PDF: Face masks and coverings for the general public: Behavioural knowledge, effectiveness of cloth coverings and public messaging https://royalsociety.org/-/media/policy/projects/set-c/set-c-facemasks.pdf?la=en-GB&hash=A22A87CB28F7D6AD9BD93BBCBFC2BB24 https://royalsociety.org/-/media/policy/projects/set-c/set-c...