Sorry for not being more clear djsim. I used the 2 micron thing loosely as I didn't remember if it was .2 or .02 or .002, and whatever it was, it would be substantially better than the other materials being discussed in this thread. After checking, it turns out to be .3, but only 95% effective at that size. I don't know all the technical specs on how all the different filtration systems are classified but it seemed obvious that a cutup N95 mask would be much more efficient than merely coffee filters or layered cotton. The N95 mask will filter 95% of all particles .3 micron or larger. A true hepa filter will do better than 99% of the same size particles and I don't know exactly where the micron filters fall between these two specs.
In any event, it seems that if you used a few layers of this material, coupled with several layers of coffee filters or similar course filtering material, it would work rather well. Just another idea.
