What should a diver do to prevent air embolism during ascent?

To prevent air embolism during ascent, it is essential for divers to breathe normally at all times. When ascending, the pressure surrounding the diver decreases, which causes the air within the diver's lungs to expand. If a diver holds their breath while ascending, the expanding air can create excessive pressure in the lungs, potentially causing lung over-expansion and resulting in an air embolism—where air bubbles enter the bloodstream.

By breathing normally, divers ensure that any expanding air is safely exhaled, thereby preventing the risk of over-expansion and allowing for a safe ascent. This practice of continuous exhalation during ascent helps to maintain the necessary pressure balance in the lungs and is a critical part of safe diving protocols.