On re-use of KN95: I’ve seen different sources recommend 24, 48, or 72 hours between reusing a mask. Store it in a breathable container e.g. brown paper bag; have 3 or 4 masks and rotate among them daily.
The figure I heard was that the half-life of SARS-CoV-2 outside a mammalian body is about 6 hours. So, in 24 hours, you'd expect 2^3 = 8-fold reduction in the numbers on the surface of the filter medium. 48 hours would be 8^2 = 64-fold reduction.
I've also heard 4 hours, of course. Maybe a certain virologist knows more than some article I probably read in 2020?
This is a similar estimate to what I've heard, but really, the time period is just to make sure that it dries out from respiratory secretions. Something to consider here is that things that deposit on the outside of the mask are basically being suctioned into its fibrous matrix. It's going to be hard to get them back out, even if they are technically viable.
Especially after everything has fully evaporated, I don't think anything from it is going to be meaningfully recoverable. I'm not just talking about SARS-CoV-2 there, either. But 24 hours is only the minimum time I'd wait; longer would be better, out to about 72 hours as another commenter has suggested. This is more to just dry out the mask and let anything settled on it get well and truly unrecoverable.
IMO, most biological particles that become embedded in such a mask are not going to be recoverable at all, at least those from the outside of the mask. On the inside of the mask will be wetter and maybe have a longer survival time and greater viability of recovery, but anything on that side already came from the wearer.
The "m95c" standard appears to be one that the manufacturer made up, but these masks have been tested, including by Aaron Collins, and seem to work, if they fit the particular child's face. I am not an expert and am repeating what I read, obviously.
We haven't actually tried these, but we bought them hoping they'd fit my wife's relatively small face and they turned out to be child size. Their ducklike appearance may be a feature depending on the kid.
I bought and read A Song for a New Day in January of 2020. I don't think I've ever seen something go from speculative to current events that fast.
And while that future obviously had its bad points, I could wish we paid half as much attention to ventilation as they do.
On re-use of KN95: I’ve seen different sources recommend 24, 48, or 72 hours between reusing a mask. Store it in a breathable container e.g. brown paper bag; have 3 or 4 masks and rotate among them daily.
The figure I heard was that the half-life of SARS-CoV-2 outside a mammalian body is about 6 hours. So, in 24 hours, you'd expect 2^3 = 8-fold reduction in the numbers on the surface of the filter medium. 48 hours would be 8^2 = 64-fold reduction.
I've also heard 4 hours, of course. Maybe a certain virologist knows more than some article I probably read in 2020?
This is a similar estimate to what I've heard, but really, the time period is just to make sure that it dries out from respiratory secretions. Something to consider here is that things that deposit on the outside of the mask are basically being suctioned into its fibrous matrix. It's going to be hard to get them back out, even if they are technically viable.
Especially after everything has fully evaporated, I don't think anything from it is going to be meaningfully recoverable. I'm not just talking about SARS-CoV-2 there, either. But 24 hours is only the minimum time I'd wait; longer would be better, out to about 72 hours as another commenter has suggested. This is more to just dry out the mask and let anything settled on it get well and truly unrecoverable.
IMO, most biological particles that become embedded in such a mask are not going to be recoverable at all, at least those from the outside of the mask. On the inside of the mask will be wetter and maybe have a longer survival time and greater viability of recovery, but anything on that side already came from the wearer.
Kid's masks: https://lutema.com/collections/made-in-usa-masks/products/kids-5-layer-disposable-face-mask-with-95-particle-protection-made-in-the-usa-5-pack
The "m95c" standard appears to be one that the manufacturer made up, but these masks have been tested, including by Aaron Collins, and seem to work, if they fit the particular child's face. I am not an expert and am repeating what I read, obviously.
We haven't actually tried these, but we bought them hoping they'd fit my wife's relatively small face and they turned out to be child size. Their ducklike appearance may be a feature depending on the kid.
HALYARD FLUIDSHIELD N95 Respirators, ASTM Level 3 Face Mask, Small Size, Orange, 46827 (Box of 35) https://wwe.amazon.com/dp/B01EI9A3DW/
Sorry, corrected link:
https://www.amazon.com/dp/B01EI9A3DW/