Mucus production: Excess mucus production results from damage to the epithelial cells lining the airway. Most smokers will experience moderate to large amounts of thick mucus.

Cilia—those broomlike hairs that move mucus out of your lungs—start to repair themselves. Ten years after quitting, your risk of lung cancer is half that of someone still smoking.

Smoking can damage the ciliated cells and cause abnormal growth of the mucous cells. Thus, the lung starts secreting excess mucus while the ciliated cells lose their ability to push the mucus along.

Millions of American smokers suffer from a potentially serious lung disease that's not technically chronic obstructive pulmonary disease (COPD), a new study finds.

People who started smoking under the age of 18 are more likely to experience respiratory symptoms, such as wheezing and phlegm, in their 20s, according to research presented at the European ...

In people who took up smoking at 18 or later, the risk was around 50% higher than non-smokers. The most common respiratory symptoms were wheezing, phlegm and coughing.

Smoking and secondhand smoke can affect the immune system and cause ear infections in both adults and children. Learn more about the link between smoking and ear infections here.