My own experience in this area is from operating a sawmill.
What I have noted is that if I mill many salted logs w/o some type of dust mask or respirator, I will usually get sick for several days. Once I started wearing a respirator this problem went away.
It happened enough times that it was not coincidence.
YMMV.
I use surgical masks that have elastic loops for over the ear attachment. The stamped 3M masks stop very little dust. Better still is a fitted OSHA mask with particulate filters (purple usually). I use one with the yellow/brown filters (organic vapors) when painting or using aromatic solvents; most of them anyway. When using alcohols I breath deeply and often.