Confused about half mask sizing, filters and cartridges

I am bout to venture into the world of non-disposable respirator masks. I’ve been reading this TP page https://theprepared.com/gear/reviews/best-gas-mask-respirator-survival/ and decided that I want to get the recommended 3m half mask. That’s as far as I was able to get before getting confused.

First of all, I’m unclear about how to figure out the mask sizing. It says that most people should use a medium size, but there’s no sizing guide anywhere that I can find. (I think of myself as having a large head).

More confusingly, I got hopelessly lost in trying to figure out the cartridges and filters thing. First of all, I don’t have a clear understanding of how these things even fit on the mask, so I don’t know exactly even what shape I’m looking for. Some filters come as simply soft disks. Can I fit those on the half-face mask? Other things come as cartridges and I am having a hard time figuring out all the variants or what would actually work. I did try to find the filter and cartrdige types that the mask description recommends, but I wasn’t able to track them down.

I will say that what I want right now is just an N95 filter, or whatever the equivalent of that is. My most immediate problem is the incredible amount of smoke pollution in California. The air is very, very bad. I’ve never been able to wear a conventional, disposable N95 masks. I get massively uncomfortable in them right away, so I’m hoping that these half-face respirators will be better. Right now my priority is to have something I can use for the smoke when I go out that will also maximize my ability to breathe easily. For that reason I don’t want to go up to N100. As for preparing for other kinds of chemical or whatever emergencies, I will need to deal with that later. So, given that, what filters would I be looking for?

I would LOVE it if some kind soul who understands these maks and filters better than I do would explain to me what to look for.


  • Comments (3)

    • 7

      I’m kinda in the same boat. I haven’t invested in any serious masks or respirators but I’ve been confused too about sizing. The first result when I search says pretty much the same thing as the article. Medium works for most people unless you get a bad fit on a regular basis. Here’s the quote:

      “Most people that fit the Large respirator sizes, will know this due to past experience with items like glasses, hats, helmets or other items that end up not fitting on their heads. While it’s important to perform a proper fit test, the majority of our customers will be quite happy with the medium size respirator.”

      Source: https://www.envirosafetyproducts.com/resources/respirators-choosing-the-size.html

      I think I have a big head too but I haven’t had very many occasions where I needed special accommodation for it. So I’d feel pretty comfortable getting medium unless the price and delivery make it possible to try both. 

    • 4

      There are two major mounting interfaces: 40mm and “bayonet.” The 3M/industrial respirators typically use the bayonet style, while the more “military”/CBRN masks use the NATO-standard 40mm threaded mount. 

      The bayonet style is more of a twist-lock mount, where the 40mm thread is more like a cap on a soda bottle. 

      For the 3M-type masks, most/all of the filters you see will be for that bayonet standard, including the flat soft disc ones, the rigid plastic catridges, etc. Basically, unless it specifically says otherwise in the product description, you can assume they use the same standard mount.