What condition is characterized by the collapse of the alveolar air spaces in the lungs?

Atelectasis is characterized by the collapse of the alveolar air spaces in the lungs, leading to reduced gas exchange and difficulty breathing. This condition can be caused by various factors, including obstruction of the airways, pressure from surrounding structures, or inadequate surfactant production, which normally helps keep the alveoli open. When the alveoli collapse, the affected areas of the lung cannot participate in gas exchange, which can lead to hypoxemia and respiratory distress.

In contrast, conditions like asthma involve bronchial inflammation and constriction, pneumothorax refers to the presence of air in the pleural space that can cause lung collapse but is not directly about the alveoli, and chronic bronchitis involves inflammation and mucus production that affects airflow but does not primarily result in the collapse of alveolar spaces. Therefore, atelectasis specifically addresses the phenomenon of alveolar collapse, making it the correct choice in this context.