Last year, I spent many weekends with a heat gun, removing lead paint off the exterior of my house (built in 1910). Construction unit cost = 12 square feet per hour. Bought a box of 3M N95 respirator masks for the work, then misplaced it over the summer and bought another.
Covid-19 has pretty much turned the remaining masks into gold nuggets. I gave a few to high-risk friends. Offered the rest to my GP, but they are already well-stocked, and using face shields as well as masks. The local hospital needs tons of masks, but folks have mobilized to sew them. A few N95s won’t make much difference there.
There’s good evidence that Covid-19 has a stealth mode: spread by people with no symptoms, via small droplets in the air from talking or breathing. There’s also good evidence that general use of face masks helps to reduce viral spread. China and the Czech Republic saw lower infection rates when masks were used widely.
It’s complicated, because protective gear is in desperately short supply. Where should they go?
Most people in Ithaca are staying home and/or physically isolating, but the grocery stores are still busy. I finally decided to donate the remaining masks to checkout staff at the local Aldi’s supermarket. They are crowded, with no self-checkouts. Maybe masks will slow down the transmission rate, and reduce the number of people who need the hospital.
Construction companies often have face masks or full respirators laying around. It might be a good time to think about how best to allocate them, based on local needs.
Since masks and other PPE are in short supply, they will need to be reused and sanitized. Low heat in an oven is the most convenient way to do that. One study says a pre-heated oven at 56° C (133° F) for 90 minutes, 67° C (153° F) for 60 minutesm or 75° C (167° F) for 30 minutes. A second study says 56° C (133° F) for 15 minutes is enough to kill the virus. A third study recommends 60° C (140° F) for 30 minutes. Take your pick.
If you have enough masks, you also can rotate them without additional treatment. The SARS-CoV-2 virus has a half-life of about 1.2 hours in air, .8 hours on copper, 3.5 hours on cardboard, 5.6 hours on stainless steel, and 6.8 hours on plastic. 4 days is the recommended minimum wait before reuse.