Bumping a old thread like this is good.
There is no PTO on 99% of buses.
Also, there would be no advantage to running the compressor off a PTO vs off the front belt system. If you need more air volume, run two compressor heads.
"Don't argue with stupid people. They will just drag you down to their level, and beat you up with experience."
Patently waiting for the apocalypses to level the playing field in this physiological game of life commonly known as Civilization