A lot of people stocked up on masks during COVID, and now those masks are collecting dust. Will they still be effective when the next pandemic hits? Do masks expire? A 2019 NIOSH study put it to the test. They measured the fit effectiveness of 293 old N95 masks stored ... Read more| Smart Air
Index of DIY face masks click here Overview Note: David Troetschel of Wallfacer Design has made requested modification of design. Latest Mark 4 Design Files: Mask STL Filter Cap STL NOTE: Skip to Mark 4 design below for instructions on first viable build. Mark-4 is better ventilated, sealed and more comfortable. In response to the […]| Knowm.org