Carcinogens are in tobacco smoke and cause cancer of the lungs, mouth, gullet and bladder. Nine out of ten people who die of lung cancer are heavy smokers. Bronchitis is mostly a smoker's disease. The passages to the lungs are swollen and sore because the smoke irritates them. Tiny hairs called cilia usually keep these passages clear but these cilia are stopped working by cigarette smoke and the lungs fill with mucus and tar.
People try to remove the mucus by coughing.
This is smokers cough. Smokers get chronic bronchitis because the cilia aren't working. None smoker's get acute bronchitis. Bronchitis is caused by an infection which makes the body produce more mucus, so non-smokers' cilia can remove the mucus and the bronchitis goes. Tobacco smoke can cause sore eyes, throat, and can cause headaches.