While taking it apart to clean it, I checked my respirator exhaust valve and found a tiny splinter propping open a corner of it (no idea how it got there). Dust was piled around the edges of that opening. Kind of defeats the purpose of the respirator!
A good reminder to me to take the thing apart on a regular basis. Next time you clean yours or swap in new cartridges, take a look at the exhaust valve to make sure it’s clear and working.
Aloha,
Da Birdman