[04rob]

This has been studied. A beard does compromise the seal, but to a lesser extent on n95s than in other masks:

https://pubmed.ncbi.nlm.nih.gov/34006963/

[NDizzle]

0 to 10mm!? Some study. That’s barely a beard. Loses 40% effectivenes at 10mm.

[goodside]

No, that's the figure for KF94 and KN95 masks. For N95s it's only about a 20% loss of FFE.