What happens to particles that escape the atmosphere of planets? (not just earth).
Do they eventually form a uniform distribution of particles overtime? Do they inevitably to fall into the gravitational pull of other entities? Do a lot escape the solar system? Do they just orbit the host planet?
I've heard of using ramjets to capture interstellar particles, though not particularly feasible, so there seems to be some dispersion of particles in the universe outside of celestial bodies.
Additionally the answer here to a related question seems to indicate the leftovers from ion drives can be picked back up by earth quite feasibly, and presumably particles ejected due to just barely leaving escape velocity would be travelling much slower.