I think it's important to point out as well that there is a mesiarble difference between between the permittivity of free space and air. But to your point the difference is quite small: e_r air is 1.0006 whereas e_r freespace is 1.
While temperature and pressure do have an effect on e_r air I don't know enough to say that net movement of the particles in one direction would have a measurable effect. ~~My instinct is no.~~
Looks like lukewarm_ozone proved me wrong. https://lemmy.today/comment/13053868
We have both sugar free and full sugar. I want to say the sugar free is more popular but I don't pay that much attention.