The key to N-95 masks is the micron-level electrostatically-charged HEPA (high-efficiency particle air) cloth inside.
The same stuff is in many vacuum cleaner bags and HVAC filters which are readily available. See the “no-sew” DIY mask above.
That may be, healthcare workers are required to wear masks approved by the CDC, and not Hoover or Dyson.
I’m so impressed with the ingenuity and resourcefulness of people when push comes to shove. I enjoy watching Apollo 13 for that very reason. Never get tired of it. :)