How does smoking impact the alveoli

Cigarette Smoking. Over time, the toxins from inhaled cigarette smoke break the thin walls of alveoli, leaving larger, less efficient air sacs. ... In a smoker, this process signals the beginning of emphysema, a form of COPD. The damage from emphysema cannot be reversed.

Over time, the walls of the alveoli start to thin. This can make it hard to breathe in oxygen, and get rid of carbon dioxide.

obviously, the latter.