why cant the greenhouse gases be pushed out through the hole in the ozone layer?

Question: why cant the greenhouse gases be pushed out through the hole in the ozone layer?
- Keywords:
  greenhouse gases,
  ozone layer
Asked by mattheworgan to Arttu, Ceri, James_M, Monica, Philip on 13 Jun 2011.
- James M Monk answered on 13 Jun 2011:
  
  The atmosphere is mostly nitrogen (molecular mass 28) and oxygen (molecular mass 32). CO2 (molecular mass 44) is therefore heavier than the atmosphere on average, and tends to sink rather than rise.
  
  Helium-3, on the other hand, is extremely rare on Earth precisely because it does just float off into outer space in the way that you suggest.

Question: why cant the greenhouse gases be pushed out through the hole in the ozone layer?