An air embolism can occur when a diver ________.

An air embolism occurs when air bubbles enter the vascular system, which can happen during a rapid ascent from underwater, particularly if the diver holds their breath. In this situation, the air pressure surrounding the diver decreases as they ascend, but the air in their lungs expands. If they hold their breath, the expanding air can cause rupture in the alveoli, leading to air bubbles entering the bloodstream. These bubbles can then travel through the circulatory system, potentially causing serious complications such as blockages in vital areas.

While other factors like diving too deep, ascending too slowly, or using faulty equipment can introduce risks related to diving, they do not specifically cause an air embolism. Diving too deep primarily poses risks related to nitrogen narcosis and oxygen toxicity rather than air embolism. Ascending too slowly can lead to decompression sickness, while faulty equipment can lead to various issues but is not necessarily tied to the direct cause of an air embolism like holding one's breath during ascent is. Thus, holding the breath during ascent is the key factor that directly leads to the risk of an air embolism for divers.