This is not about how gasmasks work in general. If you have any ideas about how one of these specific ones should work, comment below.
#1: Construction mask.
This would only protect a little bit and I think it should act like the diving mask, but for radiation. It would still degrade, and it would degrade quickly, like 45 seconds or so. Found in contructions sites, hardware stores.
#2: Respirator
I guess this would just be a better construction mask. It would have a pretty kind of slow radiation drop, faster degration, but would still use filters (ie I mean the filter degrades). Found in contructions sites, hardware stores.
#3 Antique Mask
This would be found in museums, and have no radiation drop but the filters would go by quick. Slower than the Respirator though. The filter would also have to be found on muesum areas as well.
#4 Modern Mask
(Yes, this image is of an airsoft mask). I guess, basically like the gasmask we already have.
#5 Scorpion 7 radiation suit
This would have no filters, but a slowish degrade on the whole suit. These could be stackable up to two, but should take up like, the size of your hands slot so…5 by 4. They would be extremely rare and be the best option. Spawns in scorp 7 areas.
*Note, the degration only happens to these in a deadzone, or toxic area. All the masks except for the rad suit and construction mask have separate filters for each.