Those type of masks have been on the market for a few years now and seem to sell well. I have yet to see any of them certified to any standard of any kind. I'm not going to put anything on my face that hasn't got an approval. A couple sheets of toilet paper held over your nose will filter down to 0.1 microns but that doesn't mean it filters all or most of them, and sorta some isn't good enough for me. If the companies involved won't go to the trouble or expense of certifying them then their claims are just as reliable as the things a politician will say to get elected. :evil:
Turned into a rant but you know what I think now. :wink:
I looked up the testing lab and they do pre-certification testing for the NIOSH N95 standard. That would suggest RZ are on the road to getting an approval to one of the mask standards. RZ does state a higher level of filtration with a different test that I couldn't find on the Nelson site. Digging a touch further on other sites, N/R/P 95 masks filter a minimum of 95% of particles to .3 micron. The letter designations are the resistance to oil. N being not resistant, R somewhat and P strongly resistant. The higher standard masks certified to N or P99 filter 99% of particles to .3 micron and N and P 100 filter to 99.97%. RZ's F1,F2 &F3 numbers are not a standard but a designation for different product filters that fit in the mask.
No matter how fine the filter material is, if the Mask does not have a perfect face contour seal then its filter level is rather irrelevant as it's not stopping anything that you are breathing in past the leaking seals.