Chronic bronchitis emphysema and lung cancer can be caused by?

Smoking..,: The most common cause for both diseases is cigarette smoking. By either avoiding smoking or quitting if you do smoke, you reduce your chances of getting these diseases. See your doctor if you need help to quit.

Smoking, etc...: As noted, smoking is a critical factor: http://www.Cancer.Net/cancer-types/lung-cancer/risk-factors-and-prevention http://www.Lung.Org/lung-disease/bronchitis-chronic/understanding-chronic-bronchitis.Html.