Describe the contents of smoked tobacco in terms of the particulate and gaseous phases

Question

What will be an ideal response?

Answer 1

Answer: When a smoker inhales from a lit cigarette, the temperature at the tip rises to approximately 1,700 degrees Fahrenheit as oxygen is drawn through the tobacco, paper, and other additives. This accounts for the bright glow as a smoker inhales from a cigarette. At this intense heat, more than four thousand separate compounds are oxidized and released through cigarette smoke. The smoker inhales the result as mainstream smoke, usually screened through the cigarette filter and cigarette paper. As mentioned earlier, the sidestream smoke that is released from the burning cigarette tip itself is unfiltered, and because it is a product of a slightly less intense burning process occurring between puffs, more unburned particles are contained in the smoke.

In general, we can speak of two components in tobacco smoke. The particulate phase, consisting of small particles (one micrometer or larger in diameter) suspended in the smoke, includes water droplets, nicotine, and a collection of compounds that will be referred to collectively as tar. The particles in tar constitute the primary source of carcinogenic compounds in tobacco.

The second component is the gaseous phase, consisting of gas compounds in the smoke, including carbon dioxide, carbon monoxide, ammonia, hydrogen cyanide, acetaldehyde, and acetone. Among these gases, carbon monoxide is clearly the most toxic. This diverse collection of physiologically active toxins is quite unique to tobacco. One way of putting it is to say that the fifty thousand to seventy thousand puffs per year that a one-pack-a-day cigarette smoker takes in
amount to a level of pollution far beyond even the most polluted urban environment anywhere in the world.
Carbon Monoxide
Carbon monoxide is an odorless, colorless, tasteless, but extraordinarily toxic gas. It is formed when tobacco burns because the oxidation process is incomplete. In that sense, burning tobacco is similar to an inefficient engine, like a car in need of a tune-up. The danger in carbon monoxide is that it easily attaches itself to hemoglobin, the protein inside red blood cells, occupying those portions of the hemoglobin molecule normally reserved for the transport of oxygen from the lungs to the rest of the body. Carbon monoxide has about a two hundred times greater affinity for hemoglobin than does oxygen, so oxygen does not have much of a chance.
Carbon monoxide is also more resistant to detaching itself from hemoglobin, so there is an accumulation of carbon monoxide over time. The ultimate result of carbon monoxide is a subtle but effective asphyxiation of the body from a lack of oxygen. Generally, people who smoke a pack a day accumulate levels of carbon monoxide in the blood of 25 to 35
parts per million blood components (p.p.m.), with levels of 100 p.m. for short periods of time while they are actually smoking. Greater use of tobacco produces proportionately higher levels of carbon monoxide. Carbon monoxide is the primary culprit in producing cardiovascular disease among smokers, as well as in causing deficiencies in physiological functioning and behavior.
Tar
The quantity of tar in a cigarette varies from levels of 12 to 16 mg per cigarette to less than 6 mg. It also should be noted that the last third of each cigarette contains 50 percent of the total tar, making the final few puffs far more hazardous than the first ones. The major problem with tar lies in its sticky quality, not unlike that of the material used in paving roads, which causes it to adhere to cells in the lungs and the airways leading to them. Normally, specialized cells with small, hair-like attachments called cilia are capable of removing contaminants in the air that might impede the breathing process. These cilia literally sweep the unwanted particles upward, in a process called the ciliary escalator, to the throat, where they are typically swallowed, digested, and finally excreted from the body through the gastrointestinal system.
Components in tar alter the coordination of these cilia so that they can no longer function effectively. The accumulation of sticky tar on the surface of the cells along the pulmonary system permits carcinogenic compounds that normally would have been eliminated to settle on
the tissue. As will be discussed later, the resulting cellular changes produce lung cancer, and similar carcinogenic effects in other tissues of the body produce cancer in other organs.

Nicotine is a toxic, dependence-producing psychoactive drug found exclusively in tobacco. It is an oily compound varying in hue from colorless to brown. A few drops of pure nicotine, about 60 mg, on the tongue would quickly kill a healthy adult, and it is commonly
used as a major ingredient in insecticides and pesticides of all kinds. Cigarettes, however, contain from 0.5 to 2.0 mg of nicotine (depending on the brand), about 20 percent of which is actually inhaled and reaches the bloodstream. This means that 2 to 8 mg of nicotine is ingested per day for a pack-a-day smoker, and 4 to 16 mg of nicotine for a smoker of two packs a day.17

Inhaled nicotine from smoking is