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How do you decide when to change N95/FFP-2 masks?

Finally, at the highest tier of protection, you can buy powered air purifying respirators for $300 or make your own for $15-30. I don't have any experience with either option, so I can't comment much.


The usual problem with (all?, most? of) the personal-use, non-professional PAPRs, including the $300 example you mentioned, is that they haven't been independently tested by anyone.

With the DIY PAPRs you mentioned, you at least know that the filters should work (since they're certified for hospital use) and when you build it, it's easier to ensure that the seals also work.

Delta variant: we should probably be re-masking

While disposable N95 respirators can sometimes offer better protection for the wearer than any mask, they're not that great due to the generally poor fit they provide.

Despite the high risk of leaks, N95s are probably a better solution for source control than masks due to their ability to filter out aerosols.

Reusable elastomerics offer better fit and more protection (N100) than N95s. There's also some non-anecdotal evidence that elastomerics are more comfortable than N95s. For me, elastomerics are more comfortable than even a surgical mask (due to less humidity and heat buildup) if wear time is long enough and if not engaging in a lot of physical activity.

The best N100/P100 particulate filter for a respirator is probably the 3M 2291 due to its lower pressure drop (that means it takes less effort to inhale) and that restricts respirator choices to the 3M 5000, 6000, 6500, and 7500 series (excluding respirators with full facepieces). Anecdotally, the effort to breath through the 2291 seems almost the same as breathing through an N95 filter. The 6500 and 7500 series probably has a somewhat better faceseal due to the more pliable silicone material that they use. Silicone also makes the faceseal hypoallergenic. I've seen some anecdotal reports that the 7500 is more comfortable than the 6500 due to (supposedly) slightly more pliable silicone. Personally, I've felt no significant difference in comfort between the rubber faceseal of the 6000 and the silicone faceseal of the 7500.

It's been claimed that a lot of fake filters are on the market, so I'd try to acquire them from a reputable source like an established hardware distributor.

Delta variant: we should probably be re-masking

The best study (an RCT) I've seen claims that cloth masks made no statistical difference in case reduction, whereas surgical masks reduced risk by 11% and 35% for people over 60. The study authors speculate that if more people wore masks (less than 50% did), this risk reduction would probably increase. The study was done in Bangladesh from November to January, and I suspect that the variants in circulation at that time were a lot closer to the less contagious original strain. If that's the case, it would be less likely that more mask wearing would increase risk reduction as the authors claim.

Effective PPE could have stopped the surge, whereas masks didn't. Therefore, masks offer poor protection. Studies likes these only quantify how poor that protection actually is.

Recommendations should be based on the best approaches available rather than on trying to guess the personal preferences of most people. I'm sure that the "embarrassing, uncomfortable, and inconvenient" argument was leveled against masks at the start of the pandemic but most people don't complain about them too much today. The same mistake was repeated during the winter surge for disposable N95s. However, there were some exceptions like Germany and California which started recommending N95-equivalent PPE. I find N95s too uncomfortable to wear, but I feel a lot better wearing elastomerics. Should my subjective personal preferences form the basis of general recommendations? No, and I don't see why your preferences or speculations about the preferences of others should either.

COVID/Delta advice I'm currently giving to friends

4. If you do worry about it...

...wear effective PPE (elastomeric respirator + eye protection or PAPR) and never worry about it again.

Covid 8/5: Much Ado About Nothing

Another potential problem with giving up is that you may get reinfected multiple times if enough dangerous variants emerge and your risk of death and long covid may dramatically increase.

Covid 8/5: Much Ado About Nothing

Another point that should be emphasized is that the longer people don't have access to effective vaccines and also don't have adequate protection (respirators and PAPRs), the more likely it will be for more dangerous variants to evolve. This situation is a repeat of what happened during the start of the pandemic when mask wearing was discouraged: it allowed the virus to spread like wildfire and accelerated the emergence of dangerous variants.

Covid 8/5: Much Ado About Nothing

The argument depends on the population. If people have access to effective vaccines, then effective PPE like elastomeric respirators are probably not needed except perhaps by the most risk-averse individuals. I say "probably" because there still seems to be a bit of uncertainty about long covid even for the vaccinated. At any rate, elastomerics should still be recommended as a replacement of masks in case a variant comes along and makes vaccines significantly less effective or as an option for people that still don't trust vaccines. This would also encourage the public to get used to the idea of using respirators for future pandemics and give a larger part of the public motivation and more time to prepare. For the rest of the world where vaccines are scarce or of poor effectiveness (and given the fact that masks don't seem to work all that well against variants), respirators could be used as a bridge to vaccination or other effective medical interventions.

Calls for more effective PPE for the public is nothing new but has mostly fallen on deaf ears. Elastomerics were mentioned on this site and in a few other places near the start of the pandemic but were mostly were ignored. There was a push during the winter wave for better PPE, but instead of switching to respirators, multi-layered masks were recommended in the US for poor personal preference reasons. Germany started to recommend everything from surgical masks all the way up to disposable (and often leaky) respirators but elastomerics were not mentioned as far as I know. I haven't bothered looking for more recent face covering recommendations of other countries, but I highly doubt that any are recommending elastomerics, and the WHO (like the CDC) certainly doesn't mention respirators at all. The situation is a lot worse for PAPRs. Very few people know that these things exist and even fewer know that cheap (and seemingly effective) PAPRs are possible; even I wasn't aware of the things until a few months ago. This persistent and widespread avoidance of recommending effective PPE for no good reason seems bizarre and quite insane.

Covid 8/5: Much Ado About Nothing

The same reasoning was deployed against wearing masks and doing most of the restrictions and I suspect also against switching from masks to respirators before and even during the winter wave. Millions died as a direct result of this poor reasoning. The same mistake is being repeated in countries that have little access to vaccines. Millions more will die there, if they haven't already. And what if it will become clear that vaccines won't be able to prevent (due to some variant worse than Delta) another massive wave of infections that leads to lots of long covid and death? Should the arbitrary personal preferences about face coverings of a handful of policy makers determine the fate of millions or even billions of people? No, the lesson should be that how you feel about personally using an option shouldn't shape general recommendations or public policy; all reasonable options should be presented and the public should be allowed to choose which option to use, if any.

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