Don't think about the non-ant particles, it won't help.

If you smelled poop even if it's far away, then poop particles have gone inside your nose, and yes. Tha nose cavity is connected to your mouth cavity.

Good luck sleeping, knowing that whenever you smell disgusting things, they are now also inside your mouth.

Honestly, kind of a blessing. It's not like you could do much about it if you knew.

When you smell a fart, molecules from someone else's asshole are inside your nose

I mean, your bed is home to tens of thousands of microscopic bugs as well. I'd rather not smell them.