I'm curious what everyone thinks of these. They are shipped and sold directly by Amazon and appear to be ASTM Level 2 rated by the manufacturer/supplier (Pac-Dent) that seems to be a dental supply firm with various FDA registrations for their other products, trademarks, etc.
However reviews are mixed saying it comes with a note inside indicating not to use in a medical environment.
If they are indeed ASTM level 2 then they should be able to filter out 98% of particles down to 0.1 microns.
There's also a DIY site with two cheap options for providing a proper seal with these type of masks:
Masks from Amazon: https://smile.amazon.com/gp/aw/d/...es_section