Product Code Database
Tobacco smoke is a aerosol produced by the incomplete combustion of tobacco during the tobacco smoking of cigarettes and other tobacco products. Temperatures in burning cigarettes range from about 400 °C between puffs to about 900 °C during a puff. During the burning of the cigarette tobacco (itself a complex mixture), thousands of chemical substances are generated by combustion, distillation, pyrolysis and pyrosynthesis. Tobacco smoke is used as a fumigant and inhalant.
Tobacco smoke may be grouped into a particulate phase (trapped on a glass-fiber pad, and termed "TPM" (total particulate matter)) and a gas/vapor phase (which passes through such a glass-fiber pad). "Tar" is mathematically determined by subtracting the weight of the nicotine and water from the TPM. However, several components of tobacco smoke (e.g., hydrogen cyanide, formaldehyde, phenanthrene, and pyrene) do not fit neatly into this rather arbitrary classification, because they are distributed among the solid, liquid and gaseous phases.
Tobacco smoke contains a number of toxicologically significant chemicals and groups of chemicals, including polycyclic aromatic hydrocarbons (benzopyrene), tobacco-specific nitrosamines (NNK, NNN), (acrolein, formaldehyde), carbon monoxide, hydrogen cyanide, (nitrogen dioxide), benzene, toluene, (phenol, cresol), (nicotine, ABP (4-aminobiphenyl)), and . The radioactive element polonium-210 is also known to occur in tobacco smoke. The chemical composition of smoke depends on puff frequency, intensity, volume, and duration at different stages of cigarette consumption.
Between 1933 and the late 1940s, the yields from an average cigarette varied from 33 to 49 mg "tar" and from less than 1 to 3 mg nicotine. In the 1960s and 1970s, the average yield from cigarettes in Western Europe and the USA was around 16 mg tar and 1.5 mg nicotine per cigarette. Current average levels are lower. This has been achieved in a variety of ways including use of selected strains of tobacco plant, changes in agricultural and curing procedures, use of reconstituted sheets (reprocessed tobacco leaf wastes), incorporation of tobacco stalks, reduction of the amount of tobacco needed to fill a cigarette by expanding it (like puffed wheat) to increase its "filling power", and by the use of Cigarette filter and high-porosity Cigarette paper. The development of lower "tar" and nicotine cigarettes has tended to yield products that lacked the taste components to which the smoker had become accustomed. In order to keep such products acceptable to the consumer, the manufacturers reconstitute aroma or flavor.
Tobacco polyphenols (e. g., caffeic acid, chlorogenic acid, scopoletin, rutin) determine the taste and quality of the smoke. Freshly cured tobacco leaf is unfit for use because of its pungent and irritating smoke. After fermentation and aging, the leaf delivers mild and aromatic smoke.
| + Tumorigenic agents in tobacco and tobacco smoke | ||||
| Polycyclic aromatic hydrocarbons | ||||
| Benz(a)anthracene | 20–70 ng | sufficient | ||
| Benzo(b)fluoranthene | 4–22 ng | sufficient | ||
| Benzo(j)fluoranthene | 6–21 ng | sufficient | ||
| Benzo(k)fluoranthene | 6–12 ng | sufficient | ||
| Benzo(a)pyrene | 0.1–90 ng | 20–40 ng | sufficient | probable |
| Chrysene | 40–60 ng | sufficient | ||
| Dibenz(a,h)anthracene | 4 ng | sufficient | ||
| Dibenzo(a,i)pyrene | 1.7–3.2 ng | sufficient | ||
| Dibenzo(a,l)pyrene | present | sufficient | ||
| Indeno(1,2,3-c,d)pyrene | 4–20 ng | sufficient | ||
| 5-Methylchrysene | 0.6 ng | sufficient | ||
| Quinoline | 1–2 μg | |||
| Dibenz(a,h)acridine | 0.1 ng | sufficient | ||
| Dibenz(a,j)acridine | 3–10 ng | sufficient | ||
| 7H-Dibenzo(c,g)carbazole | 0.7 ng | sufficient | ||
| N-Nitrosodimethylamine | 0–215 ng | 0.1–180 ng | sufficient | |
| N-Nitrosoethylmethylamine | 3–13 ng | sufficient | ||
| N-Nitrosodiethylamine | 0–25 ng | sufficient | ||
| N-Nitrosonornicotine | 0.3–89 μg | 0.12–3.7 μg | sufficient | |
| NNK | 0.2–7 μg | 0.08–0.77 μg | sufficient | |
| N-Nitrosoanabasine | 0.01–1.9 μg | 0.14–4.6 μg | limited | |
| N-Nitrosomorpholine | 0–690 ng | sufficient | ||
| 2-Toluidine | 30–200 ng | sufficient | inadequate | |
| 2-Naphthylamine | 1–22 ng | sufficient | sufficient | |
| 4-Aminobiphenyl | 2–5 ng | sufficient | sufficient | |
| Formaldehyde | 1.6–7.4 μg | 70–100 μg | sufficient | |
| Acetaldehyde | 1.4–7.4 μg | 18–1400 μg | sufficient | |
| Crotonaldehyde | 0.2–2.4 μg | 10–20 μg | ||
| Miscellaneous organic compounds | ||||
| Benzene | 12–48 μg | sufficient | sufficient | |
| Acrylonitrile | 3.2–15 μg | sufficient | limited | |
| 1,1-Dimethylhydrazine | 60–147 μg | sufficient | ||
| 2-Nitropropane | 0.73–1.21 μg | sufficient | ||
| Ethyl carbamate | 310–375 ng | 20–38 ng | sufficient | |
| Vinyl chloride | 1–16 ng | sufficient | sufficient | |
| Inorganic compounds | ||||
| Hydrazine | 14–51 ng | 24–43 ng | sufficient | inadequate |
| Arsenic | 500–900 ng | 40–120 ng | inadequate | sufficient |
| Nickel | 2000–6000 ng | 0–600 ng | sufficient | limited |
| Chromium | 1000–2000 ng | 4–70 ng | sufficient | sufficient |
| Cadmium | 1300–1600 ng | 41–62 ng | sufficient | limited |
| Lead | 8–10 μg | 35–85 ng | sufficient | inadequate |
| Polonium-210 | 0.2–1.2 pCi | 0.03–1.0 pCi | sufficient | sufficient |
In spite of all changes in cigarette design and manufacturing since the 1960s, the use of filters and "light" cigarettes has neither decreased the nicotine intake per cigarette, nor has it lowered the incidence of lung cancers (NCI, 2001; IARC 83, 2004; U.S. Surgeon General, 2004). The shift over the years from higher- to lower-yield cigarettes may explain the change in the pathology of lung cancer. That is, the percentage of lung cancers that are has increased, while the percentage of squamous cell cancers has decreased. The change in tumor type is believed to reflect the higher nitrosamine delivery of lower-yield cigarettes and the increased depth or volume of inhalation of lower-yield cigarettes to compensate for lower level concentrations of nicotine in the smoke.
In the United States, lung cancer incidence and mortality rates are particularly high among African American men. Lung cancer tends to be most common in developed countries, particularly in North America and Europe, and less common in developing countries, particularly in Africa and South America.
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