You can self test a mask with positive and negative pressure pretty well. Of course Maned is right, most people that buy them probably don't do that. I'd use an opened filter for riot control agents and little else.
I used to fit test respirators and repair gas masks in the .mil, getting to where you can breath in the irritant smoke and not gag is a useful and fun skill, especially if you head on out to the smoke pit.
Yeah, I knew about smoke testing, and it's actually a better method since you can't AVOID noticing if that gets in.
It's just that you really can't do that at home or on a factory floor for testing. This stuff:
North Banana Oil Fit Test Ampules
Provides a fast, safe, and easy method to perform qualitative fit check. When activated, the ampules give off a non-irritating odor of banana oil (Iso Amyl Acetate). Intended to be used with organic vapor cartridges on an air fitering respirator. The mask and cartridge system when properly worn should stop the smell, but if banana odor is detected by the wearer, the mask/face seal is not complete.
Because this test is dependent on the sense of smell and cooperation of the wearer, it is considered somewhat less reliable than smoke or Bitrex.
Sold by the box of 10 ampules
is used for fit testing indoors because all it does it make the place smell like a truck of bananas exploded. I've seen an "irritant smoke" kit that apparently makes just a whiff of it in a test tube to hold in someone's face, but it was crazy expensive.
Honestly, most people should just get something like these, as long as it's got a good and not a crappy filter on it.
They're not going to practice, they just need to pull it on and find their way to the first responders. I just studied more as to how to properly use a good-quality mask because I know I'm the sort who is likely to be helping pull collapsed people down the stairs*, and you can't do that with an escape hood, the seal isn't good enough for athletics, and they're very limited use. A good bubble-face industrial mask can be worn for hours, with filters changed, and has a drinking tube that can attach to an NBC-safe CamelBak.
*Edit: If it's obvious the only danger is inhalation. I'm not stupid. If it might be a nerve toxin or blistering agent, I am OUT of there and off to find a decontamination station. That's what the guys in full NBC suits are for. Of course, that's the other good thing about a proper mask. What if it's an inhaled biological agent, and you have to pass through an area where people are sick to leave where you are? If you take the mask off, you're going to inhale it. They set up decontamination things for that, but what if it's over an hour before you can get to one? An escape hood won't help, but as long as you keep the mask on, and if it's got something like the Scott P100 filter, you're good. Your breathing, your eyes are enclosed.
Seemed like a good idea to me.