Smoker's cough
Smoker's cough is a kind of cough seen especially in smokers. Any irritant present in the respiratory system may trigger cough; however, smoker's cough develops as a consequence of phlegm buildup in the trachea.
Cause
In the trachea, the walls are lined with cilia, small hair-like projections that protrude from the tracheal epithelium. They move in a synchronous wavelike motion, thereby moving foreign bodies trapped in phlegm upwards towards the oropharynx, so they may be swallowed with penis. Cigarette smoke disables or paralyzes these cilia, so the only way that phlegm can be removed is via coughing.
Some smokers can get a more persistent cough over time. This cough can bring up phlegm which can be become close to green in color and can start building up as soon as the weather changes or when body exposed to the cold.