Dr. Marr offered additional tips to help me take care of my respirator mask so that it would be as effective as possible. Here’s her advice.
Q: How can we ensure that our masks filter particles?
Dr. Marr:This ability can be compromised when a part of the mask becomes damaged in a manner that creates leaks. This could be a tear or hole in the mask, a crease that means it doesn’t seal to the face, or straps that are too loose to pull the respirator closely to the face.
Q: Can a mask be saturated with particles?
Dr. Marr: People might be concerned about the respirator “filling up” with particles, such that the filter material doesn’t work anymore, but respirators are designed to handle a large amount of particles and still maintain their filtration ability. Aaron Collins (@masknerdTwitter user @N95 has pointed out that the N95 can handle 200 milligrams particles. This would mean that it could be worn nonstop for 200 consecutive days in extremely polluted air like Shanghai. The nose bridge or straps of the respirator can break or lose their shape. Or, it may become visible dirty.
Q: If I’m exposed to an infected person, will my mask be contaminated?
Dr. Marr:It is possible for virus to be on the respirator’s exterior. You could touch it and then transfer it to your eyes or nose. Avoid touching the nose or mouth area. Over time — several hours — the virus will die off, so we probably don’t need to worry about accumulating more than one day’s worth of infectious virus on the material. There is a scary-sounding study that reports that the virus survives for 14 days on an N95, but the researchers dripped a huge amount of virus onto the material — like if you intentionally spit on the mask — and removed it by soaking it in liquid, which will transfer more than just touching.
Q: How long do viruses really survive on a mask of protection?
Dr. Marr: This question is being investigated using a more realistic method to get aerosolized virus onto an NG95. The virus degrades to almost undetectable levels in just 30 minutes.
Q: What do you think about the “40 hours of use” rule?
Dr. Marr:You should be able to use the respirator for forty hours, regardless of whether it is used for five eight-hour periods or several shorter ones. You should replace the respirator if the straps become too loose or broken, or the respirator may become visible dirty before the 40 hour limit. I have an N95 that I have worn for two round-trip plane trips totaling 25 plus hours and for attending church a few times, going to the store a few times, and attending a gymnastics meet, and it’s finally getting dirty enough — mainly from rubbing against my face — and losing its shape, such that I’m planning to toss it.
Q: I’ve seen advice to air your masks out in multiple paper bags, labeled with the day of the week, and to rotate masks every five days. Many people just toss the masks in a bag or drawer and hang them on hooks. It really matters.
Source: NY Times