I wear a dust mask whenever I use power tools or do hand sanding, even though I work outdoors.
-> I am especially careful to wear a dust mask when I am cleaning up, which stirs up the most sawdust from any of my activities, and those are the finest, worst particles of all.
I have used several kinds of dust mask, but settled on an RZMask for comfort. Filters for RZMasks are sold out, and I wonder when I will be able to order them again. For woodworking, a filter is supposed to last 60 hours. (They must be assuming that you never sneeze or have a runny nose in one, eeew!) I have a couple extra filters on hand, but if I run out, I will make them myself with whatever appropriate materials are on hand.
I wish I had known more about the dangers of sawdust back in the 1970s, 1980s, 1990s, 2000s, ...
Come to think of it, I wish I had known more about the dangers of excessive noise back in the 1970s, 1980s, 1990s, 2000s, ... too.