We Use an Irritant Smoke

The Respiratory Fit Test
This is the rite of passage where you try on a special mask that covers your nose & mouth to make sure you have the correct size that will prevent you from inhaling airborne pathogens like tuberculosis or [insert your favorite airborne pathogen].  In all the hospitals where I've done rotations, an aerosolized form of saccharin is used to test the fit of the mask; if you perceive a sweet taste after the saccharin is sprayed, your mask does not fit properly. My fit test this week was conducted by an RN in the Occupational Health building.

Military Occupational Health RN: Most places use saccharin to conduct the fit test, but we use an irritant smoke
Me: What?!

It's true!  She was literally blowing smoke at me after I applied the N-95 respirator mask, and she had me turn my head in various directions, count to 10, and bend forward at the waist, all to prove that the mask fit snugly enough to prevent smoke from entering my airway.  It was after she allowed me to remove the mask that I was fully exposed to the "irritant smoke" and promptly launched into a prolonged coughing fit.  Now I feel like I have emphysema.