In chronic bronchitis, exposure to tobacco smoke and other lung irritants over time can lead to inflammation in the airways that deliver air into the lungs (bronchial tubes). As a result, the airways produce more mucus than they would normally. Inflammation and extra mucus reduce air flow and cause coughing. Mucus production and inflammation over many years may lead to progressive and permanent lung damage.
eMedicineHealth Medical Reference from Healthwise
To learn more visit Healthwise.org