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A comment on You Probably Should Be Wearing a Face Mask If You Can. Parent comment

Re:You Probably Should Be Wearing a Face Mask If You Can by bagels on Monday March 30, 2020 @08:06PM (#22733564)
Do you feel that if someone has an old construction mask in their garage from years ago that it is not ethical to wear it?
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Re:You Probably Should Be Wearing a Face Mask If You Can by benjohnson on Monday March 30, 2020 @11:48PM (#22734776)
Of course it's ethical to wear it. If you have some to spare, then it may be ethical also to share with others.

We've been donating some of our N95 masks to the local hospital, but I'm not donating all of them. My family is important too.

As for age, I have noticed that the older ones had crumbly rubber foam and the straps are more delicate, but the melt-blown fabric itself seems perfectly fine. We've re-strapped some with new elastic and replaced the foam with closed-cell foam.

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Re:You Probably Should Be Wearing a Face Mask If You Can by TylerE on Monday March 30, 2020 @08:14PM (#22733645)
It may not be effective. Shelf life is usually rated at something like 5 years.
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Re:You Probably Should Be Wearing a Face Mask If You Can by pmoriarty on Monday March 30, 2020 @09:13PM (#22734047)
It's far from clear how long masks will be effective against SARS-CoV-2 (aka Coronavirus) for.

First, when testing their masks for their effectiveness, the manufacturers of these masks were certainly not testing them against SARS-CoV-2, as it didn't exist five years ago. Even now, it's very unlikely any manufacturers are testing their masks against SARS-Cov-2. What they were probably testing them against is various toxic fumes and smoke -- the things they're actually rated to be effective against, not viruses.

Second, some filters used in respirator-style masks have charcoal in them, and that charcoal will absorb fumes from the environment while in storage, so depending on what environment a filter is stored in and for how long the charcoal may not be as effective at absorbing various toxic fumes and smoke that these filters were tested for, but for all we know they may still be quite effective against filtering out SARS-CoV-2 viruses.

Third, it's well known that some manufacturers put bogus expiration dates on their products, and the products are good well past the expiry date. This is a phenomenon well known in the food industry. I'm not sure how widespread it is among mask manufacturers, but I wouldn't put it past them to also have unreliable expiry dates.

The CDC has some guidelines regarding the use of expired masks: [1][2] and they approve of the use of some such expired masks. However, it's not clear what tests they actually used to decide on the suitability of such masks, and if these masks were actually tested against SARS-CoV-2. It is pretty unlikely that they had randomized, double-blind trials of hundreds of people wearing masks and hundreds not and exposing them all to SARS-CoV-2 to see which got infected. Their tests were probably much more imperfect, and so their results less reliable.

All in all, there's just too little information to know how effective expired masks are against infection by SARS-CoV-2, but they're probably better than nothing.. especially the ones the CDC has blessed in their research.

[1] - https://www.cdc.gov/coronavirus/2019-ncov/release-stockpiled...

[2] - https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/FAQ-N95.aspx

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Re:You Probably Should Be Wearing a Face Mask If You Can by angry_octet on Monday March 30, 2020 @08:28PM (#22733751)
And studies have shown only a small decrease in effectiveness of technically expired masks.
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Re:You Probably Should Be Wearing a Face Mask If You Can by orangecat on Monday March 30, 2020 @08:26PM (#22733741)
It's almost certainly better than nothing.
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