Hygienic masks
Medical/anti-infectious masks
2020-08-01 — 2025-11-03
Wherein the reader is informed that elastomeric respirators with P100 (P3) filters are recommended as reusable, better‑fitting alternatives to disposables, and simple fit hacks are described.
This is not necessarily the same thing as particulate masks, at least as far as priorities. [TODO clarify] Obviously, some masks filter both well, but their priorities may differ. For example, many particulate masks have a release valve, which, as far as I can tell, isn’t ideal for protecting other people if we wear one. Of course, protecting ourselves from disease with a mask still benefits others, because we can’t transmit a disease we don’t have. Also, a mask that’s comfortable and effective is more likely to be worn properly. The practical outcomes of these trade-offs are probably best estimated empirically.
1 Effective hygienic masks
- Elastomeric respirators such as the 3M 6200 with P100 filters are reusable, fit better than disposable N95 masks, and provide high filtration.
- As far as I can tell, the Australian equivalent of the US P100 certification is P3
- These are cost-effective if we bear in mind they have a long shelf life and can be stocked up for future use. Gold standard.
Australian suppliers
2 Cheap hygienic masks
As we saw during COVID, people usually don’t have stockpiled elastomeric respirators, so we make do with what we have.
Jeremy Howard, Cloth masks can protect the wearer:
As we all know now, the science shows that DIY masks are particularly good at protecting those around you in case you’re infected with COVID-19. But that doesn’t mean that you can’t do a lot to protect yourself too.
Unfortunately, many public health bodies still incorrectly claim that there is no evidence that DIY masks are useful at protecting the wearer. There’s actually plenty of evidence they can. Effective protection for the wearer of a mask depends on three critical things:
- Material: does the mask filter particles of the appropriate sizes?
- Fit: do particles squeeze in through the gaps of your mask?
- Sanitation: can you clean and re-use the mask?
There’s a much more useful summary and advice there; it’s now published as (Brooks 2021).
Fixthemask notes a few bonus hacks, including using a rubber band to keep masks snug.
If we don’t want to hunt for weird filter types on eBay, there’s the smart air guide that ranks common fabrics and household filters.
How to Double Mask Correctly covers double masking, the latest, low-lift version of mask upgrades. [TODO clarify]
Enough practicalities! Here, have some silly fashion! Facemasks of your face. Glowing masks that are fibre optic!
3 Particulate masks
For protection against pollution. See particulate masks.
4 Efficacy
It’s a difficult problem because there are many confounders. At a population level, efficacy is unclear according to the closest thing to meta-reviews we can contrive (Talic et al. 2021). Some studies report no effect for recent variants, which may be due to the paucity of RCTs on this question. It’s certainly contentious (Vainshelboim 2021). There are also some interesting decision theory angles (Muller 2021).