The National Academies Press has a free download “Reusability of Facemasks During an Influenza Pandemic: Facing the Flu (2006)“. Unfortunately they see a huge need for more research in the area, so the advice tends to be a bit of a guess.
The National Academies Press has a free download “Reusability of Facemasks During an Influenza Pandemic: Facing the Flu (2006)“. Unfortunately they see a huge need for more research in the area, so the advice tends to be a bit of a guess.