well, I have been putting it off for too long, getting a better respirator. I have a full beard... especially if I've had soup for supper, but I digress. A full beard and a respirator are not generally considered compatible. I have worn a mask that covered the nose and mouth, and just cinched the straps up, and have probably kept the bigger chunks out of my innards, but the finest dusts are the ones that really cause the problems, I suppose. Well I found an outfit called the Resp-o-rator, which has a HEPA filter for the fine dusts. It has a scuba-like mouthpiece, and the pair of filters hang behind the neck, out of the way. An exhaust valve is just under my snout. No problem with fogging up my glasses, or even interfering with the fit of my glasses over the bridge of th' nose. Bought it off the internet - there were a handful of sources, with widely ranging prices. I got mine from Hartville tool co for $38 bucks plus change plus shipping, ymmv
I have no connection with this company or the respirator company, just telling you about what I got. Seems to be okay, so far, just a bit dry in the mouth in the low humidity.
tom koehler