Chronic bronchitis is most frequently caused by long term irritation of the bronchial tubes. This can be caused by exposure to airborne pollutants such as cigarette smoke, excessive dust in the air, or chemicals.

The bronchial lining becomes inflamed and the constant exposure begins to damage the bronchioles (the smallest airways in the lungs).

Symptoms of chronic bronchitis include shortness of breath or wheezing, chest pain or tightness in the chest, and a chronic productive cough.