FFP3-V masks
“Recommendations to protect against the avian flu indicated that using a face mask with a rating of N99, N100 or P100 in the United States or a rating of FFP3 in Europe should be effective in protecting against transmission.[84] While face masks with these ratings provide 99% or greater efficiency in protecting against flu transmission, N95 or FFP2 face masks provide about 94% efficiency.[85] N95 and FFP2 rated face masks may therefore also be effective.”
wikipedia, swine flu outbreak 2009
very fine dust may be able to get through but the one I bought today say they are N95 and offer a barrier for sanding, drywall and fiberglass. Don’t know what else there is out there but those granules are about as small as they get.
Viruses don’t free float on the air all alone, they have to be carried on something, minute particles of saliva or mucous which will definitely be filtered out of a properly worn N95 mask.