I think it is about filtering. Even simple cotton t-shirt cloth is about 50% effective at filtering 23nm microbes. Definitely not good enough to give to a healt

I think it is about filtering. Even simple cotton t-shirt cloth is about 50% effective at filtering 23nm microbes. Definitely not good enough to give to a healthcare worker in a high exposure environment, but also definitely good enough to flatten the curve when used at a population level. https://www.researchgate.net/publication/258525804_Testing_the_Efficacy_of_Homemade_Masks_Would_They_Protect_in_an_Influenza_Pandemic https://www.researchgate.net/publication/258525804_Testing_t...