Nicotine

Smoking 10: Bursting air sacs

Heavy coughing does further damage to the weakened air sacs (alveoli). They may even burst open.

If many air sacs become damaged, that will reduce the capacity of the lungs to transfer oxygen to the blood and absorb carbon dioxide. You will grow short of breath even after mild exertion. This is called ulmonary emphysema.

Tar and nicotine can hence cause bronchitis, cancer and emphysema.