Chapter 5 
Cigarette Smoke Components and Disease: 
Cigarette Smoke Is IVIore Xhan a Xriad of Xar, 
Nicotine, and Carbon IVIonoxide 
Jeffrey E. Harris 
INTRODUCTION Cigarette smoke is a complex mixture of chemicals. Some smoke 
components, such as carbon monoxide (CO), hydrogen cyanide (HCN), and 
nitrogen oxides, are gases. Others, such as formaldehyde, acrolein, benzene, 
and certain N-nitrosamines, are volatile chemicals contained in the liquid- 
vapor portion of the smoke aerosol. Still others, such as nicotine, phenol, 
polyaromatic hydrocarbons (PAHs), and certain tobacco-specific nitrosamines 
(TSNAs), are contained in the submicron-sized solid particles that are 
suspended in cigarette smoke. 
In view of this chemical complexity, cigarette smoke has multiple, 
highly diverse effects on human health. It is not unexpected that multiple 
chemicals in cigarette smoke can contribute to any single adverse health 
effect. 
Thus, HCN may affect the human respiratory system by its toxic effects 
on the cilia that line the respiratory tract. At the same time, HCN may cross 
the placenta and have toxic effects on the growing fetus. In addition, HCN 
also may cause nerve damage in cigarette smokers with optic neuropathy 
(Costagliola et al., 1989). Although the PAHs and TSNAs in the particulate 
phase of cigarette smoke are known carcinogens, catechols and phenols in 
the particulate phase also are considered carcinogens or tumor promoters. 
Benzene and formaldehyde in the liquid-vapor portion of the smoke also 
may be carcinogenic. 
Aside from specific chemical constituents, certain physical-chemical 
properties of smoke may participate in disease processes. Thus, the pH of 
the smoke may affect the site and degree of nicotine absorption as well as the 
smoker's depth of inhalation. The oxidation-reduction state of the smoke can 
be important because oxidants influence the maturing of cholesterol-laden 
plaques in the coronary arteries and other blood vessels. In short, cigarette 
smoke is far more than a triad of tar, nicotine, and carbon monoxide. This 
fact needs to be considered carefully in any discussion of the adequacy of 
current cigarette testing methods or current cigarette labeling practices. 
MAINSTREAM VS. Both smokers and nonsmokers can incur adverse health 
SIDESTREAM effects from the smoke of burning cigarettes. Smokers inhale 
CIGARETTE SMOKE mostly mainstream (MS) smoke, which is drawn through 
the burning tobacco column and filter tip and exits through the mouthpiece 
of the cigarette. Nonsmokers inhale mostly sidestream (SS) smoke, which is 
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