In a former life I was a chemical engineer and worked under and designed fume hoods for all sorts of purposes. First, you all may be a little too concerned about the chemicals used in AP. Some chemicals used for processing color are a little obnoxious but are probably less dangerous to humanity than a lot of the materials used almost daily stashed under your kitchen sink (when used improperly).
Certainly good ventilation is important anytime you use chemicals. Skin and eye protection is also important. If you are really seriously worried about inhaling vapors or other airborne particulates, there are good disposable masks available in every hardware store. I use one when mowing – not while mixing and dissolving developer.
A parable: One fine day I needed to go to our division office located in the front of the building. I took the opportunity to walk around outside and enjoy the view of the Naval Academy. When I approached the front door, there were eight (8) pieces of emergency equipment surrounding the door with men-in-white running hither. It seems that someone broke a thermometer (Hg, you know). Our gang had to laugh as in circ. 1968, we worked with liquid Hg daily and had several “accidents” in the form of Hg being sprayed around rather liberally. No one was harmed in the making or clean up of our messes. Same with concentrated KOH, H2, O2 (combined H2/O2), and more baddies. Note: The worse disasters centered around the generation and handling of high pressure O2.
So a little fixer in the air poses no particular problem – but I am old, worthless, and don’t have long to live, or anything to contribute to life – and I’m sure I’m not going to become pregnant. Those who do / are/ may, might need to be a little more careful, but not too much….
Good luck in your endeavors and may the Force be with you.