During inhalation, a person's diaphragm and intercostal muscles contract, expanding the chest cavity and lowering the internal air pressure below ambient so that air flows in through the mouth and nose to the lungs. Suppose a person's lungs hold 1260 mL of air at a pressure of 1.00 atm. If they expand their chest cavity by 485 mL while keeping their nose and mouth closed so that no air is inhaled, what will be the air pressure in their lungs in atm? Assume the air temperature remains constant.