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Comment by quanto | Hacker News Reader

Fit is critically important. There is no point in having an advanced filter material if the mask fit itself is leaking air everywhere.

>"An N95 is more protective because it has a better face seal in general than a KN95 or a KF94,"

N95 does not require manufacturers to test for fit. However, the headband normally ensures a better face seal. KF94 has a fit-test requirement, but it's bar is low -- 11% leakage to pass the test. The ear-loops really don't do much and in terms of face seal and filtering inbound air. Leakage is far greater source of pollutants than the filter failure (94%, 95%, 99% filtration).

I use common sense -- if the mask fits loosely and is easy to breathe in with, it probably is not filtering much.

Edit: I didn't mention anything about politicized matters or even covid. I discussed the mask certification standards and filtration effectiveness (well established before the pandemic).

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>and is easy to breathe in with

My understanding is that for Covid your mask is expected to filter exhalation, protecting others from any virus you may have in your system. My understanding is that masks do very little to protect you from inhaling unwanted virus carrying particles.

Of course, it seems to me that a good mask should really be doing both jobs at once, with a good seal. Which means no beards and headbands. My understanding since the beginning of this pandemic was that everyone was going to get this bug, it was just a matter of "flattening the curve". So, why are we still talking about masks? I sometimes fear that the right has turned it into a political issue, and in response the left has ALSO turned it into a political issue, instead of a rational one.

Cloth masks do little to protect you on the way in but do catch quite a lot on the way out even with side leaks. The intuition there is the tiny wet globs of fluid flying out of your mouth from breathing etc are pretty heavy and catch on the mask easily when fresh. That helps a lot. If not caught they dry out, becoming lighter and smaller, and then float in the air at infectious levels for up to a few hours. At a system level getting almost everyone wearing at least cloth masks helps slow spread down a lot.

Once you're dealing with exposure to an environment filled with the fine airborne particles you need a well-fitted N95 or better to protect yourself. Although the virus itself is tiny it's traveling in particles closer to 1 micron which N95 type filters work great for. You can still be infected through your eyes but as far as I know that's very rare in normal non-hospital settings.

So that's self-protection, but why bother? It's true that at this point most people will be exposed eventually and with three shots of the mRNA vaccines people are unlikely to end up in the hospital. Several reasons. First, slowing rate of transmission will reduce overloading the hospital system. That saves a lot of collateral damage to people with otherwise treatable problems when they get turned away due to the crowds. Second, if you are unlucky enough to get sick enough to need a hospital bed you want that to happen when there is plenty of capacity, availability of drugs, etc. Third, the treatment regimens keep improving as the medical world learns better treatments and better drugs become available. Fourth, how sick you get appears to vary with how much virus you are exposed to. So even if your PPE is not perfect you can reduce your odds of serious effects when infected. Around half of people infected experience long-term lingering symptoms and there's evidence even in kids that number is not negligible.

It's pretty clear masks are effective both at an individual protection level and as a public health measure, I'm not sure how they got turned into such a political hot topic.

I also thought masks was about exhalation, but the general public seems to have misunderstood this from the onset. Politicians probably helped that along, since it's easier to promote selfish mask-wearing than altruism.

However, I didn't see that in HN discussions. Now it seems goal posts have shifted, and HNers also expect inhalation protection. I'm assuming N95 masks have proven effective, so the bar was suddenly raised. Or something to that effect.

I've been using FFP2 and N95s with the straps cut off, under a rather stiff cloth mask that is largely the same shape in the front as most respirators (so it doesn't crush the front), and is attached by a large velcro strap around the back the head (with holes on the side so as to go around the top and bottom of the ears). I've found this easier to put on and take off quickly, while maintaining at least as good a seal.

KN95s are a bit confusing to me in that, in my experience, they definitely don't have the common sense "this air is clearly being pushed through a filter" feel of breathing through a well-fitted FFP2/N95, but at the same time, don't give an obvious sense that there is a leak somewhere.

The two are not mutually exclusive.

I find most N95s easier to breath in the many cloth masks simply because they actually hold their shape and don't collapse into your mouth every time you inhale.

> if the mask [...] is easy to breathe in with, it probably is not filtering much

For the past 2 years, haven't pro-mask people been telling anti-mask people to stop pretending that masks are so hard to breathe with?

It takes more effort to wear an N95 than nothing. But it’s certainly not impossible, and for most people (including my overweight, out-of-shape self), it’s not insurmountable.

It’s like wearing pants. You’d have a lot more mobility if you didn’t, but we do it anyway.

I’m not asphyxiated, but after 15 minutes in a KN95 I can definitely tell that something is on my face. I had zero problems with cloth.

It’s fair to say that opponents have overblown the negatives, but there are negatives.

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