It's amazing that well-educated people who would never tolerate asbestos in their homes would place themselves in similar danger on a daily basis by working in their glass studio without wearing a protective mask. And yet, for my beginning years doing stained glass, I was one of those people.
I can't believe now that I spent countless hours leaning over my glass grinder, intent on cleaning up and smoothing the edges of my glass pieces, never realizing that all the microscopic glass bits I was grinding off were attaching themselves to water vapor droplets and sailing right into my lungs with every breath I inhaled. In my defense, my teacher never ever mentioned the need for a mask, but in retrospect, why the heck didn't I see that for myself? Maybe it's because I was SO intent on making my art, that I never gave it a thought. But now I do.
Like asbestos, fine glass shards and powders get trapped in the body. They don't dissolve, they don't flush away. They build up over time, and eventually they interfere with the functioning of the cells and air passages in our lungs. So it's important to BE AWARE of the occasions where air- or water-borne glass, enamel, or other particles can be drawn into our vulnerable lungs, and PROTECT ourselves.
The best protection, of course, is wearing a mask that will filter these particles out. What follows is a very rudimentary discussion of masks. You can find lots of technical information on the web; this is just meant as a simple introduction. Here are some of the masks in my studio currently:
The thinner, lighter masks (the white ones shown at top) are easier to wear and you can find them at any drugstore or hardware store. I've got several, and I hang them within reach near work areas so I remember to put them on. I find that they work well for me when I'm hand-sifting glass powders, enamels, pigment powders, or any other non-toxic powders that I'm applying by hand.
I also wear a mask when I'm scraping kiln wash off of kiln shelves or molds. And I try to wear a mask when I'm scraping up and disposing off the powdery residue of kiln-shelf paper after firing.
However, when it comes to machine work--sawing, drilling, grinding, or engraving glass--it's best to invest in a 3M mask with replaceable filters, such as the one shown at the bottom of the photo. I found this one at a home improvement store (you can also get these online). The pink cartridge areas are where the filters are housed. This mask has squarish filters; others have round filters.
These masks have two main differences from the little white ones:
a) The mask part that fits on your face is plastic, and it's designed to seal against your skin so that the only air reaching your nose is air that has been drawn through the filters.
b) The filters are much better--they filter out smaller particles, including vapor-borne particles. This protects your lungs much better as a result.
c) After you've worn the mask for a while, you can replace the filters.
The downside of these is that they are more cumbersome to take on and off; it's harder to breathe through them; and they are not as comfortable. But you have to weigh that against the risks of lung disease or cancer, and then, it's really worth wearing it.
In addition to wearing a mask, there's one other thing you can do when working with powders, and that is: keep it damp. That means, when you're done with your powders, don't sweep up the residue with a brush; use a damp paper towel instead. Wipe up surfaces with a damp cloth, sponge, or paper towel (I prefer the last because we have a septic system and I try to keep as much foreign material out of it as possible, so I just toss out the paper towel). If you want to use a can of compressed air to "blow dry" your sifters, just take it outside. Even then, wear a mask!