The air pressure in a soccer ball is essential for its performance. The correct air pressure for a soccer ball is 0.6 - 1.1 atmosphere (8.5 - 15.6 psi). The ball should be inflated before each game or practice and should be checked for proper pressure. If the ball is too soft or too hard, it can affect the ball's bounce and flight. It is important to make sure the ball is properly inflated so that players can have maximum control over the ball.