After getting a question in the BIDA Facebook group, I was curious what mask policies contra dances are using. I looked at the dances marked as active on trycontra.com and checked their websites for mask requirements ( sheet).

Of the 56 dances that have resumed, 31 (55%) require masks. Of those 31:

  • 2 (6%) require surgical or better.
  • 4 (13%) require a surgical + cloth or better.
  • 4 (13%) require high-filtration masks (N95, KN95, KF94, etc)

Now that high-filtration masks are widely available, it does seem like a weird compromise to require masking but allow low-filtration options like cloth or surgical, especially when I haven't seen anyone wearing a P100. Specifically:

  • Most of society is no longer requiring masks: bars, nightclubs, workplaces, transit, etc. In MA, one of the more cautious states on this issue, the state requires masks only in healthcare, paratransit, shelters, and jails.

  • This means that the reason to require masks at dances is to allow people to attend for which it would otherwise be too risky.

  • A group wearing surgical masks poses a risk to individuals (wearing the mask of their choice) that is roughly (per microcovid) 1/4 as risky as if the group were fully unmasked.

  • An individual wearing a P100 is at ($16) (again, per microcovid) about 1/7 the risk of one wearing a high-filtration mask.

This means that if a group switches from masks-required to masks-optional and more cautious individuals switch to P100s, risk to those individuals very likely goes down.

Which then has me wondering: why do we see people saying that dances need to require masks, but not wearing P100s? Some guesses:

  • People have adjusted to high-filtration masks now being available, but not to the availability of P100s.

  • The P100 masks are more expensive up front. On the other hand, the part you wear lasts years, the replacement filters are ~$6/pair, and a filter pair lasts much longer than a disposable high-filtration mask, so the cost should be similar or lower over time. I also suspect that in most communities people who prefer dancing without a mask would be willing to cover the cost of P100s for people who need them if we could sort out a good way to do this?

  • People may think P100s are less comfortable. My experience is that they are a bit more comfortable: slightly more pressure on the face but more spread out, and much less resistance to breathing.

  • They have vents. This is an issue in places that require masks, since masks with vents are usually prohibited. Microcovid estimates that they provide a small amount of filtration on exhaust, about the same as a well-fitting cloth mask and about 3/4 as much as a surgical mask. I think they probably shouldn't be prohibited unless you're also disallowing cloth masks? This is also not an issue if masks are optional.

  • They look weird. That, I will definitely grant, but I don't think that is enough of a reason to require everyone else to wear masks? And, of course, a dance full of masked people would have looked pretty weird in January 2020.

Overall, I think a policy of optional masks and subsidized P100s would be much better than just "masks required" (currently the most common thing for dances to do). I think it's likely also better than requiring high-filtration masks for everyone, but I'm less confident there.

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I've been reading LessWrong too long. I thought the title meant "an argument against dance mask policies".

i’d argue it’s a pun

I wear a P100 sometimes, and it's incredibly hard for other people to hear what I'm saying when I'm behind one, which would be a factor.

I think in this particular situation it's not bad? It's not an activity where people do that much talking.

This means that the reason to require masks at dances is to allow people to attend for which it would otherwise be too risky.

Or urge the people that think it's too risky to attend to wear a respirator, instead of requiring everyone to wear one.

A group wearing surgical masks poses a risk to individuals (wearing the mask of their choice) that is roughly (per microcovid) 1/4 as risky as if the group were fully unmasked.

Microcovid is (still!) using outdated data (2020 and older) that doesn't take into account the current covid variants that are far more contagious than the early-to-mid 2020 strains. It should be painfully obvious by now that surgical and cloth masks likely provide close to zero protection against these variants.

P100 is at ($16)

No one should buy that thing. It's a (not NIOSH-approved) knockoff of the 3M 6000 series. Just buy a real 3M (or other NIOSH-approved model/brand) reusable, elastomeric respirator and filters from a reputable distributor.

urge the people that think it's too risky to attend to wear a respirator, instead of requiring everyone to wear one.

Yes, that is the policy I recommend at the end of the post.

doesn't take into account the current covid variants that are far more contagious than the early-to-mid 2020 strains

I don't think that affects the argument in the post, which is about relative risk? Unless you're saying that the new variance are better at getting past cloth/surgical masks but not at getting past P100s?

No one should buy that thing. It's a (not NIOSH-approved) knockoff of the 3M 6000 series.

The filters claim to be NIOSH approved; are you claiming they're counterfeit, or that the solid portion is uncertified?

You're right; I missed your end-of-post recommendation.

Yes, I'm saying that the newer variants can easily get past cloth and surgical masks but are highly unlikely (but not impossible due to faceseal leaks) to defeat elastomeric respirators equipped with P100 filters. This is due to the fact that P100 filters filter out nearly all particles, so the contagiousness of a virus doesn't matter that much. Here's another way to think about it: during a poison gas attack, what would you choose, a water-soaked handkerchief or a gas mask?

The whole thing (facepiece and filters) is a knockoff, and as far as I can tell, it's not NIOSH-approved. Again, you can check for yourself.

P100 are nice, but it's very hard to find a disposable P100 that actually seals to the face properly like disposable N95/ffp2 do. Since sars-cov-2 is primarily spread via aerosols the most important thing is not the absolute filtration effectiveness of your mask but instead to completely seal it. An N95 sealed with medical tape to the face will far outperform an P100 that has a couple mm^2 gap along edges and nose.

Full P100 respirators made of rubber and plastic do seal well, but yeah, they almost always have an exhaust valve with a small aperture. This makes these impossible to filter manually because the pressure drop is too high.

The best option in most situations is an N95/ffp2 that is sealed to the face. Masks that don't fit or seal properly are more of a fashion statement. Anything that requires masking for sars-cov-2 reasons should require fitted masks that seal.

Full P100 respirators made of rubber and plastic do seal well, but yeah, they almost always have an exhaust valve with a small aperture.

In this case, the idea is to use them in a mask-optional environment, where it then doesn't matter whether their output is filtered?

There are several elastomeric respirators that are ventless or that have add-on vent filters. I've heard that some of these respirators are not that comfortable to wear for long periods of time due to increased humidity, rather than pressure drop or C02 accumulation. I've tried a 3M 6000 series respirator with the 3M 604 exhalation valve filter, and I've noticed no significant increase in breathing difficulty, but I didn't use it long enough to determine if humidity accumulation is a problem.

Ventless disposables can also have humidity issues, so you're probably better off with an elastomeric anyway.