Chronic bronchitis is a long-term inflammation of the bronchi, which are the airways that carry air to and from the air sacs in the lungs. The most common cause of chronic bronchitis is cigarette smoking, but exposure to air pollution and irritants in the workplace can also play a role
. People with chronic bronchitis tend to get lung infections more easily and have episodes of acute bronchitis when symptoms are worse. To be classified as chronic bronchitis, a person must have a cough and mucus most days for at least 3 months a year, for 2 years in a row, and other causes of symptoms, such as tuberculosis or other lung diseases, must be ruled out
