Emphysema is a long-term (chronic) lung disease. In emphysema, the tiny air sacs (alveoli) at the end of the airways in the lungs are damaged and lose their stretch. When the air sacs are damaged or destroyed, the inner walls break down and the sacs become larger. These larger air sacs move less oxygen into the blood. This causes difficulty breathing or shortness of breath that often gets worse over time. After air sacs are destroyed, they cannot be replaced.
Emphysema is a type of COPD (chronic obstructive pulmonary disease). Emphysema is usually caused by smoking. Air pollution can also cause emphysema. Other things that may lead to it include breathing chemical fumes, factory dust, soot, or secondhand smoke over a long period of time. Some people get emphysema because they have a disorder that runs in families, called alpha-1 antitrypsin deficiency.