My mind was rather blown when I read on the CDC site about the last resort of DIY masks. Scroll down to very last paragraph before the footnotes: Strategies for Optimizing the Supply of N95 Respirators: Crisis/Alternate Strategies If that’s the case, please read: Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic? Disaster Medicine and Public Health Preparedness 7(4):413-418 · August 2013  Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic? Then scroll down to the carpenter dude video for instructions: Ashfall protection: 4 substitutes to N95 mask