How Long Can I Keep Wearing the Same Respirator Mask?

 "Based on the five-day rule for health workers, and assuming they wear the mask all day over an eight-hour shift, that suggests about 40 hours of use per mask, said Anne Miller, executive director at Project N95, a nonprofit that vets and sells high-performance masks. Many of us wear a mask in 15- and 30-minute increments as we pick up a kid at school or run some errands, which means one mask could last weeks. Realistically, if you’re taking a mask on and off frequently, your mask will most likely become soiled or the straps will break before you hit the 40-hour mark.

Never try to clean your high-performance mask. While it may feel like synthetic fabric, respirator medical-style masks are made of layers of high-tech filters that have been electrostatically charged to better attract and trap particles. Washing a mask, or trying to sanitize it with alcohol, peroxide or even ultraviolet light will degrade it and make it less effective. Just let your mask air out on a hook, in a paper or mesh bag or on a clean shelf. The best way to keep your mask clean is to wash your hands before touching it, hold the mask by the straps, and keep it in a clean, dry place when you’re not wearing it. Keep a few masks on hand and rotate their use so each mask has plenty of time to air out between uses.

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 (@masknerd on Twitter) points out that an N95 is designed to handle 200 milligrams of particles, which would be equivalent to wearing it nonstop for 200 days in very polluted air such as in Shanghai. The straps or nose bridge will break, the respirator will lose its shape, or the respirator will become visibly dirty before this happens.

How long does the virus stay on the mask? We are studying this question using a more realistic way of getting aerosolized virus onto an N95, and the virus decays to nearly undetectable levels in 30 minutes."