Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Emphysema ?
    ### Response:
    Emphysema is a type of COPD involving damage to the air sacs (alveoli) in the lungs. As a result, your body does not get the oxygen it needs. Emphysema makes it hard to catch your breath. You may also have a chronic cough and have trouble breathing during exercise.
    