What about pepper spray?

Medium sized (molecular mass 305 g/mol) capsaicin molecules disscolved in alcohol. They come out of solution and get stuck when alcohol tries to find its way through a filter.

Much more potent than any kind of tear gas. Cannot be used as easily in ranged weapons. Flammable. Cops don’t break it out as easily. Also works on cops. Gratitude for a 20-second demonstration of function and first aid goes out to Bulgarian cops. :)

A long time ago, I once volunteered to be pepper sprayed for a test by a fellow anarchist from close range. I was wearing winter clothing, a hood, a fur hat, working goggles (polycarbonate goggles with air holes underneath and above, some of them probably blocked by the hat) and a scarf before my nose and mouth. I breathed out during the process (this is critically important). After being sprayed, I ran for 10 paces to get away from any residual vapour cloud.

I experienced mild discomfort. I believe (perhaps mistakenly) that a P99 (FFP3) mask would reduce effect on airways to tolerable levels, but protection around eyes should have good coverage. But in a protest / confrontation / riot setting, I would recommend a mask with colorful stripes on the filter (protection against multiple chemicals) just to be on the safe side.

On another occasion (a drunken husband beating his wife in the corridor of an apartment building) I have pepper-sprayed a person who hit me, after a warning that I would retaliate if he did that again. He almost blanked out and was not able to walk to his apartment for half an hour. That’s what happens if the spray is good and hits the mark. I brought some water and washing supplies but those didn’t help him much.

P.S. Do not expose any skin. Thick clothing will stop it, thin clothing - not so much. Rinse all skin hit by a liquid. Do not rub. I have pepper sprayed myself accidentally (lifting a heavy object against my leg pushed the lid down on the can). A burning sensation on my leg started in 3 minutes and remained 30 minutes after thorough rinsing. It would have grown very uncomfortable without access to water.

Also, with pepper, contaminated items are really contaminated. Touching those items and then touching your face is a big no-no. Washing in the wrong order can bring contamination to a new area.