THE HUMAN NOSE: “Particles larger than 3μm have a maximum deposition in the anterior part of the nose (nasal valve). Particles smaller than 3μm & larger than 0.5μm are filtered by the nasal mucosa and transported by cilia propulsion to the nasopharynx.”
THE N95 MASK: The filtration material itself of N95’s average pore size ~0.3−0.5 μm [larger average pore size is just like the mucosa filter of the NOSE] does not block finer aerosol laden with virions penetration, not to mention surgical masks. For example, see Balazy et al. (2006).
CONCLUSION: THE HUMAN NOSE is as good a filter as an N95 mask given the N95 mask has many pores which are equal in size to the filtration capacity of the nose of 0.5μm.
HOWEVER breathing mouth to mask NEBULIZES aerosols into smaller particles making them potentially more infectious to other people’s lung alveoli: