What is nitrogen tire inflation?
Some people think that tires will last longer if filled with nitrogen instead of air. Air contains about 21 percent oxygen, which is known to gradually weaken tires through the process of oxidation. Nitrogen has no known bad effects on tires.
If you look at your tire that's on your car it tells you waht to put into it if not ..I just put 24psi in my sunfire.. Conventional wisdom on tire inflation is to inflate to the pressure indicated on the plaque on the driver's side door jamb. The pressure shown on the tire is the MAXIMUM inflation for that tire. It's not intended to be an inflation recommendation.
Tire inflation is simply adding more air or less air to the car. If you are referring to inflation as in the price of the tire then this is caused by the price of the components the tire is constructed of. The price of rubber being the main cause of price increases in tires. Of course shipping costs and labor costs are also a factor.