Originally Posted by
SoSmellyAir
This is not a tubeless sealant answer, but CO2 is a smaller molecule than air (i.e., mostly N2 and O2) and thus more prone to leak out of the tire (or tube), so it is recommended to deflate and re-inflate with air after returning home.
It didn't make sense to me that CO2 would be smaller than O2 given that it contains both the O2 molecules plus a carbon. Of course, how atoms actually combine may not be intuitive. So I looked online and it does seem that CO2 is a larger molecule than O2 or N2, not a smaller molecule.