Final answer:
The condition where alveoli walls break down creating larger chambers is emphysema, a chronic lung disease primarily caused by smoking, which decreases the lungs' ability to exchange gases.
Step-by-step explanation:
The condition in which the walls of the alveoli break down, creating fewer and larger chambers, is called emphysema. This chronic lung disease is usually caused by smoking and results in reduced gas exchange in the lungs. The damage to the alveoli is irreversible and leads to symptoms like shortness of breath, especially during exertion, and a chronic cough. In contrast to conditions like pneumonia, where the alveoli fill with fluid, emphysema involves the destruction of alveolar walls, thereby decreasing the surface area for gas exchange and causing air to become trapped in the lungs at the end of exhalation.