The so-called air bubbles in the lungs are pulmonary alveoli, the most common causes of pulmonary alveoli are several. First, chronic obstructive pulmonary disease, often the lung CT can be seen with emphysema, if the alveoli continue to increase, increase to a certain extent, there are two alveoli or more alveoli connected together will form a large alveoli, there is no lung texture on the chest CT. Second, the chest CT of normal people, can also appear alveoli, such as a violent cough after a cold, can cough up the alveoli, two or more alveoli fused together to form alveoli. Third, pulmonary alveoli in the elderly. In many elderly people, there is emphysema and pulmonary alveoli on chest CT, but the patient does not have obvious signs of wheezing. Fourth, smoking. Check the chest CT to see that the lungs can have large pulmonary alveoli, often more patients who smoke, it is recommended to quit smoking.