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Concept
Tobacco smoke
Résumé
Tobacco smoke is a sooty aerosol produced by the incomplete combustion of tobacco during the 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.
List of additives in cigarettes
The particles in tobacco smoke are liquid aerosol droplets (about 20% water), with a mass median aerodynamic diameter (MMAD) that is submicrometer (and thus, fairly "lung-respirable" by humans). The droplets are present in high concentrations (some estimates are as high as 1010 droplets per cm3). Most cigarettes today contain a cigarette filter, which can reduce "tar" and nicotine smoke yields up to 50% by several different mechanisms, with an even greater removal rate for other classes of compounds (e.g., phenols).
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), aldehydes (acrolein, formaldehyde), carbon monoxide, hydrogen cyanide, nitrogen oxides (nitrogen dioxide), benzene, toluene, phenols (phenol, cresol), aromatic amines (nicotine, ABP (4-Aminobiphenyl)), and harmala alkaloids. The radioactive element polonium-210 is also known to occur in tobacco smoke.
Source officielle
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