Here is a easy way to have compressed air whenever and wherever you need it. First you will need an air compressor capable of pumping up to 3000 psi(207 bar).
I use an old MAKO compressor.
Next you will need one or more SCUBA tanks. I have eight.
Then you will need a yoke and regulator.
I only fill mine to 2500psi.
They will last a surprisingly long time and you will always have air when you need it...