The lungs produce mucus to trap chemical and toxic substances.
Small “finger like” hairs, called cilia, coat the lung's airways and move rhythmically to clear this mucus
from the lungs. Combined with coughing, this is usually an effective method of clearing the lungs of
harmful substances. Tobacco smoke paralyzes these hairs, allowing mucus to collect in the lungs of
the smoker.16 Cigarette smoke also promotes goblet cell growth resulting in an increase in mucus.17
More mucus is made with each breath of irritating tobacco and the smoker cannot easily clear the
increased mucus.