Clearly, smoking is something people do for a variety of different reasons. Some may be doing it because it makes them feel better physically – at least temporarily, while others may also be doing it to satisfy psychological needs or in response to social pressures. Once they get into the habit, they may find it a hard one to break, not only because of the way their bodies may react physiologically, but also because of the millions of cues that subtly direct them to repeat the behavior ten, twenty, maybe forty times per day.
Smoking poses two basic health hazards. One is the drug-induced response the body makes to cigarette smoke. Nicotine, for instance, is capable of creating a true physiological dependence; it also creates tolerance, and tolerance may also develop to the tar and carbon monoxide in cigarettes. The other hazard is the toxic substances, or poisons, that enter the individual’s body as he or she inhales smoke. Cigarette smoke contains compounds that, when taken over many years, are quite harmful.
The average cigarette produces about one-half gram of smoke when it burns. To help determine what portions of tobacco smoke are responsible for the various diseases associated with cigarette smoking, chemists have broken down the smoke into its components and tested their effects on laboratory animals. Thus far, more than 4,000 major toxic substances have been identified in cigarette smoke, and the number is still growing.
Of all the compounds in cigarette smoke, 92 percent are gaseous, and many of these are toxic. Carbon Monoxide, one of the gases found in tobacco smoke, is considered one of the most hazardous. Carbon monoxide affects our bodies in several ways, all related to oxygen deprivation:
Carbon monoxide impairs the blood’s capacity to carry oxygen, causing serious problems for people suffering from cardiovascular diseases.
Researchers have long believed that carbon monoxide is partly responsible for the heightened risk of heart attack and stroke among cigarette smokers. It may be the combination of carbon monoxide and nicotine that is at fault.
The remaining 8 percent of the smoke consists of solid (nongaseous) matter: ash, a tar-rich condensate, and a wet particulate matter comprising thousands of different substances. Tar is a sticky residue from burning tobacco, consisting of more than 200 chemicals which can be separated into three parts: acidic, basic, and neutral.
In animals tests, the neutral part shows by far the highest carcinogenic, or cancer-causing, activity. It contains benzopyrene, one of the deadliest carcinogens known, and many other chemicals of the same family.
The acidic part of the tarry condensate contains phenol and other materials that are not carcinogens but, some cancer researchers believe could activate “dormant” cancer cells so that they grow and spread.
The basic part of tar contains chemicals that have not been shown to pose a risk to human health.