I have a half mask respirator from before COVID for working with chemicals. It doesn't protect anyone but you unless you add an additional filter over the vent

I have a half mask respirator from before COVID for working with chemicals. It doesn't protect anyone but you unless you add an additional filter over the vent (affecting breathability), and the recommended lifetimes for cartridges aren't just based on it filling up with drywall. The electrostatic charge expires even as plain air and moisture go through the cartridge. I don't have the packaging for mine, but I don't remember the recommended lifetime being anywhere near 12 months. (Edit: Checking 3M's site, 6 months from the moment it's unsealed even if not used at all. Lifetime goes down from there with use, and when not used it should be in an air-tight container) - Additionally, those were sold out for a very long time from most common sources. There are people who need those to do their jobs just like any other mask, and I have no idea where you're getting the idea they're not hard to come by. Home Depot for example, no longer ships them here in the Northeast, and in-store stock is heavily limited. Actually it looks like Amazon has them back in stock, but every style I see will exhaust what you exhale (so it makes sense there's plenty to go around) If you're in a vulnerable population and cannot in any way avoid coming into contact with others I guess a respirator is better than nothing for your personal safety? But going out of your way to get respirators that people need to safely do their jobs just like the healthcare workers do if you don't actually need to is ill-advised.