Toxic effects of tobacco smoke
Tobacco smoke contains more than 4000 constituents, including carcinogens such as N-nitrosoamines and aromatic hydrocarbons, as well as toxic substances including ammonia, nitrogen oxides, hydrogen cyanide, carbon monoxide and nicotine. The carcinogens are the main cause of smoking-induced cancers – lung cancer, laryngeal cancer and urinary bladder cancer – and carbon monoxide has an important role in the aetiology of cardiovascular disease. However, it is not known precisely which constituents of smoke are responsible for the development of COPD. Nicotine plays no role in cancer or COPD and only a minor role in atherosclerosis. The constituents of smoke implicated in causing non-malignant disease are summarised in table 1 and the toxic effects of smoke are reviewed in more detail in chapter 8.