I'd never heard of them before the ads appeared in BF. Would have never considered using them even if I hadn't heard the downside.
Al

The respro mask looks pretty good, but is there any source of replacement filters other than buying official respro filters?

I don't mind paying for the mask, but the filters are way too expensive to be replaced at the recommened monthly interval.

May not look high tech, but why not just buy a cotton/charcoal face mask? The emergency models look like surgeon masks and only costs $5.00 each. Respro Techno Mask basically uses a charcoal cloth with an exhalation valve.

If you've never worn a dust mask or respirator, it can get pretty hot under there and it takes some getting used to (breathing wise). Place I used to work at, people may go through 2-3 masks for each 8-hour shift and that's just for dusty (paper dust) conditions. Disposable masks are cheaper than buying replacement cartridges for a respirator or a true "gas mask". Even a bandana could be just as effective filtering out airborne particles of a certain micron size.