Some manufacturers have put out notifications warning against the “off-label” use of some of their filters. It’s best to know what any filter you choose is made of. Just remember that when manufacturers make stuff to hold dust, etc. from your vacuum cleaner, or to filter out dust bunnies from your HVAC system, they probably weren’t thinking about how people might use them for other purposes.

Save yourself effort and frustration. 3M has a “filtrete” blanket-type filter. (They identify it as being suitable for “Hammock” type furnace filter holders.) The MERV rating isn’t as high as the Filti brand (Filti.com), but 3M is a recognized firm and if they say the filter material is MERV-12 (or whatever they say it is — look it up online), then that is what you will get. It’s apparently the same stuff that they glue to the expanded metal sheets you are having to deal with.

Finding these blanket-type filters on-line is a little difficult, but a few months ago when I bought a sheet of it, it didn’t take me that long to locate a supplier.

I suggest you look for “filti” nanofiber fabric “blankets” that you can cut to size. Filti.com has products that I think can be trusted. At least you have a known firm that has to be careful of US laws about things like claims on filtering ability. Some KN95 stuff is genuine, and KN95 doesn’t differ significantly from N95. But even the stuff that operates at N95 levels can be difficult to breathe through. It’s expensive to buy a package only to discover that the product doesn’t meet your needs.

Any of these masks, even those that don’t really reach N95 levels of efficiency, will take care of sawdust.

I do not know where you live, but in the USA your first stop might be AMAZON.com. Alternately, use Google, look for the kind of mask you want, and then use their shopping option. Back at the very beginning, I got a 3M respirator that was only about $15, but you had to order 2 N95 or better filter cartridges for around $7 each. There are other choices that come with air filters. Originally Amazon had a large selection, and you could also search for a mask, e.g., “3M model XYZ123” and “price” to find the same item being offered by various vendors. I think there is growing availability of N95 level masks. Filter cartridges last until they get too clogged up to be comfortable to breathe through.

I bought some KN95 “disposable” masks via Amazon. They looked good, but when I held the edges down to eliminate leaks they became too difficult to breathe through. I have read that many KN95 masks sold in the USA do not filter up to their alleged rating, i.e., they are faking if they claim N95 or the approximately equal KN95 status.

Unless you want to do a great deal or research, you are probably better off choosing 3M or some of the masks made by major USA (or Canadian, GB, etc.) firms. Some use designations other then the Nxx standards used by 3M, and you’ll just have to research how they stack up against each other.

Hi yuan. Song here. Thanks for reading. Those are based on the fit tests on different people.

Hi, first of all thank you for this informative article. I think Naveen meant the LVDun mask that’s last (far right) on the bar chart, because I had the same question. I noticed this type of mask is sold with the removable filter sheets. Do you know if the mask in the study had the PM2.5 filter in place or was just the mask alone?

Also, were the prices in the Effectiveness vs. Price chart adjusted for the number of uses you can get per mask? It would be kind of silly to compare the cheap price of a disposable one-time-use mask to the expensive price of, say, the reusable fabric vog mask, without accounting for how many times the reusable one can be washed and reused.

Hi Naveen, Liz here. The cotton handkerchief is something you can get online, typically a thin layer of cotton fabric with great breathability. So there’s no filter inside.