There are no 'types' of air. Air is all just air. - Some people do use nitrogen in tires - that is not air.
That depends on who old/used the type is.
The recommended tire pressure for a 2004 Hyundai Elantra is 30 psi for both the front and rear tires.
Nitrogen , check out this site, http://www.getnitrogen.org/ Typically, plain air. Nitrogen is used in high-performance racing tires and in large aircraft tires.
It depends of the tire size that you are using. If you still have the factory 13 inch tires the correct air pressure is 32psi on the front tires and 35 on the back.
Depends on the vehicle and type of tire.
Airless tires are tires which are not pumped up with air in the traditional way. Vehicles such as ride-on lawnmowers and golf buggies use airless tires.
Air or nitrogen is used to inflate tires
Helium is lighter than air. So, tires filled will helium will help the tire rise up in the air.
Air actuated devices, inflating tires and flotation devices.
A tire pressure gauge.
Compressed air or compressed nitrogen.
Nitrogen mixed with normal air