The most common cause of COPD is cigarette smoking; about 20 percent of smokers develop lung disease. Other causes of COPD are:
- breathing in dust and chemicals (vapors, irritants, and fumes), and coal dust or silica at work
- indoor air pollution from cooking fuels and heating in poorly ventilated homes
- secondhand smoke
- childhood lung infections that can lead to problems in adulthood
- inherited factors
