Your airways are lined with tiny brush like hairs, called cilia. The cilia sweep out mucus and dirt so your lungs stay clear. Smoking temporarily paralyzes and even kills cilia. Smokers get more colds and respiratory infections than non-smokers.
Benzo(a)pyrene, a constituent in cigarette smoke, induces vitamin A depletion.
Low concentrations of several micronutrients, especially the antioxidants vitamin C, folate and Vitamin B and beta-carotene, are also associated with smoking.