There are two main types of COPD:
- Chronic bronchitis (inflamed airways)
- Emphysema (damage to the lung tissue)
Chronic bronchitis and emphysema result from irritation of your airways over a long time, usually from smoking and sometimes from air pollution. Other causes are on-the-job exposure to irritants such as dust or chemicals or frequent lung infections.
Chronic bronchitis and emphysema can occur separately but they often develop together. In chronic bronchitis, the insides of the airways thicken and swell. This makes the passageway for air inside the airways smaller. The damaged airways make more mucus, which can block the airways and make it hard to breathe. In emphysema, the tiny air sacs (alveoli) in the lungs may become badly damaged or destroyed and lose their ability to stretch (get bigger and smaller). This makes it harder for you to breathe out carbon dioxide after breathing in air. As the carbon dioxide collects in your lungs, there is less room for oxygen to be breathed in.
COPD is not contagious. You cannot give it to someone or get it from someone else.