The link you posted is commercial (selling air filters), better to link to the original study from which this is based: https://www.researchgate.net/publicatio

The link you posted is commercial (selling air filters), better to link to the original study from which this is based: 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...