Emphysema is a type of lung condition called chronic obstructive pulmonary disease (COPD), characterized by coughing and breathing difficulties. This occurs when the air sacs in the lung sustain damage, or lung tissue loses elasticity. The air sac walls deteriorate or are destroyed, narrowed, collapsed, expanded, or over-inflated. It means the lungs have a smaller surface area to expand, take oxygen into the blood, and remove CO2 from the body.