No, after a while you would expect it to have settled to the floor (or other surfaces).
That is partially true - I didn't want to get into the subtleties of it too much.   You would certainly expect a non-uniform gradient of some kind on the vertical axis and indeed a lot of the virus will settle on surfaces. But it can also settle on dust, for example, and hence remain airborne for long periods, becoming airborne again any time the dust is disturbed.

As I suggested, enclosed spaces are complicated. It would not be uniform horizontally either, because furniture, electrostatic effects, positions of doors and windows and many other factors will all affect things.

The best rule of thumb model I can come up with - and I do not claim anything epidemiological studies behind this, just what 'textbook physics' might suggest! - is a background level plus an inverse square of distance contribution. If the background level is dominant, the inverse square term might be small enough to ignore; conversely if the level is very low, as it typically is in open spaces, only the distance really matters. But the background level varies continuously - each room will be different - and if, for example, to enter a open space you need to pass through a gate, that gate becomes an environmental hotspot.


The point of this ramble is to consider whether I would be happy moving to a one metre separation from a 2 metre one. And the inverse square component suggests to me that the time to do so is when the number of infected people is around a quarter of the level it was when the two metre rule was introduced, because that is, roughly speaking, an equal risk.

Anyone else is welcome to come up with a criteria of their own choosing when they will be happy with a closer distance.