Reg compressed air =
Nitrogen 78 percent
Oxygen 21 percent
Argon 0.93 percent
Carbon dioxide 0.038 percent
I have no idea what the makeup of compressed air is, I just use the compressor at our yard, and we have regular compressors on the job site at all time for our equipment.
Not sure what the value in nitrogen filled tires is, unless maybe you are a top fuel dragster or something (and even then I have no idea what they use to be honest).
But, again, around here, it’s kind of a free complimentary thing if you are a customer of the tire shop or the dealers.
Makes the white collar types feel like they are gear-heads or something I reckon.
We just use “air”.