Some serious questions about wearing masks

[kenny1999]

can I use the mask again if it's taken off for a few hours?
can I use the mask again if it's more than 8 hours, but less than 24 hours? In fact how long does it take for a mask to lose its effectiveness to somehow unacceptable

I think different masks may differ, would you please answer according to Level 2 mask because it is kind of masks we use most often

 

[Astronuc]

can I use the mask again if it's taken off for a few hours?

Yes. I've used the same mask periodically over several months. It is basically a filter, which reduces particulates passing in and out. However, I wear the mask only as long as I am in the presence of others, or indoors where folks congregate, which is often less than one hour.

One could soak a mask in alcohol and/or peroxide and let it sit overnight.

 

[atyy]

What is a level 2 mask? Which country/city are you in?

Ideally, a medical mask meant to protect a healthcare worker from infection by the patients he cares for is not reused. However, when there were shortages early in the pandemic, they were reused: various guidelines can be found at https://www.cebm.net/covid-19/exten...acepiece-respirators-a-rapid-evidence-review/

Here is a study of practices among the general public in Hong Kong:
https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-021-11346-y

 

[jim mcnamara]

N95 or KN95 masks are very effective filters. Yes, you can reuse them, see the link below. @atyy gave you what you need to know vis-a-vis effectiveness. N95 and KN95 are designations in North America, and parts of continental Asia and Japan. N95 is the surgical mask.

Reuse: https://www.ncbi.nlm.nih.gov/pmc/ar...ext=N95 Masks Can be Rotated,and 40% humidity.

 

[kenny1999]

What is a level 2 mask? Which country/city are you in?

Ideally, a medical mask meant to protect a healthcare worker from infection by the patients he cares for is not reused. However, when there were shortages early in the pandemic, they were reused: various guidelines can be found at https://www.cebm.net/covid-19/exten...acepiece-respirators-a-rapid-evidence-review/

Here is a study of practices among the general public in Hong Kong:
https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-021-11346-y

I've just read the study roughly. Looks like once a mask is taken off it shouldn't be reused again because virus could transfer from outer of the mask to inner of the mask, is it really this dangerous?

 

[Rive]

can I use the mask again if it's taken off for a few hours?

Don't forget that sanitized and/or disinfected is still not the same as 'clean'. Even if you can make sure that there are no surviving Covid virus there, some other stuff (bacteria, other viruses) may still cause problems, regardless of the preserved filtering effectiveness.

Re-use of masks is supposed to be a temporary measure, not a long term practice.

Ps.: people supposed to wash their socks or underwear after a single use. Masks are far more intimate piece of 'clothing' than socks.

 

[pinball1970]

Don't forget that sanitized and/or disinfected is still not the same as 'clean'. Even if you can make sure that there are no surviving Covid virus there, some other stuff (bacteria, other viruses) may still cause problems, regardless of the preserved filtering effectiveness.

Re-use of masks is supposed to be a temporary measure, not a long term practice.

Ps.: people supposed to wash their socks or underwear after a single use. Masks are far more intimate piece of 'clothing' than socks.

I use mine for a day then discard as per the instructions (GB/T 32610-2016 – imported from China to the UK)

If I am on a particularly packed train, tube or tram then I discard after that journey and get a new one out but this is fast and loose, a judgment call on my side.

I sanitize if I can, depending where I am before handling a new one (I keep a stash in my ruck sack)

 

[atyy]

I've just read the study roughly. Looks like once a mask is taken off it shouldn't be reused again because virus could transfer from outer of the mask to inner of the mask, is it really this dangerous?

In a high risk situation (healthcare worker interacting with patients), ideally a mask should not be reused. If there is a shortage, extended use is better than reuse.

However, in Singapore, where a mask is needed by law in public during the pandemic (except during eating, smoking etc), and safe distancing is mostly still in place, and there are relatively few new cases per day (about 100 in a population of 5 million), most people, including myself, reuse our masks (ie. if I take the mask off to eat, I use the same mask after the meal).

BTW, I hope you are not asking about masks in place of getting vaccinated. If you have the opportunity to be vaccinated, you should take it as soon as possible. And get both doses (and boosters etc if your local health authority recommends them).

 

[Rive]

I sanitize if I can,

Sorry, in this context my usage of this word may be misleading. By 'sanitizing' in this topic I use the word regarding masks only, and I mean to disinfect them by UV-light, ozone, sprayed alcohol or simply by leaving them dry for a few days (or some other methods). The common point is, that this won't remove the foreign material but only kill Covid (and maybe other germs, but not necessary all of them).
While the result may be temporarily safe, the foreign material present even if it is sterile it is still a good food for germs. So it is not the same as 'clean', by any means.

In case of a 'light' environment short term re-use may be considered safe, but on long term (few days at most) masks must be replaced (or properly washed, if it's possible), even if the cumulative usage was short.

Regarding 'sanitizing' in general, the problem is the same. Sanitizing (hands) usually means rubbing them with some alcohol or so. That's great to kill some germs, but everything (dead germs, grease/fat, dead skin cells, dirt) remains. Short term it's OK, but still definitely not the same as 'clean'.