The top three causes of chronic obstructive pulmonary disease (COPD) are smoking, smoking, and smoking. Tobacco smoke inflames and irritates the airways in your lungs and gradually damages the air sacs that provide oxygen to the blood. This limits the amount of air that can flow into and out of the lungs.
However, even nonsmokers and ex-smokers can get COPD. Exposure to air pollutants (including years of workplace exposure to industrial dust and fumes) can cause COPD. Other COPD risk factors include low birth weight and rare genetic factors.