I’m sorry that you are having to deal with realities that preclude you from protecting yourself adequately from contaminants, that you used to be able to protect yourself from.
It is what it is.
It is easy to make something makeshift that will filter large particles (as opposed to viruses), instead of the other way around, but the n95 do a better job of it, and are disposable.
I was hoping by this time the market would be flooded with good masks that could be had cheap.