Is epiratory reserve volume the amount of air that moves in or out of the lungs during a normal breath?

No, expiratory reserve volume (ERV) is not the amount of air that moves in or out of the lungs during a normal breath. Instead, ERV is the additional volume of air that can be forcibly exhaled after a normal expiration. The amount of air that moves in or out during a normal breath is known as tidal volume.