[lkmill]

i believe so, https://en.wikipedia.org/wiki/Maxwell%E2%80%93Boltzmann_dist....

2k years is a long time for gas dispersion in such a "small" volume as the earth's atmosphere. early weather behaviour probably affected the distribution unevenly, but by now it should be relatively evenly distributed across the globe. no more or less in rome or italy. this is, however, as we say in sweden, a "guy's guess".