An air compression apparatus has a frame, a tank, and a motor. A drive mechanism is operably connected to the motor and at least one piston assembly is operably connected to the drive mechanism and configured to move within a respective cylinder mounted to the frame. The piston assembly includes: (1) a piston body; (2) a piston rod having a hollow bore connected at one end to the drive mechanism and at an opposite end to the piston body; and (3) a piston valve installed on the piston body. In use, upward travel of the piston body as caused by the drive mechanism acting through the piston rod opens the piston valve and allows ambient air to be drawn through the hollow bore into the cylinder, and downward travel of the piston body closes the piston valve so as to compress the air within the cylinder.