Tobacco smoke mainstream

Zhangyu, C., M. Yiyuan, and Y. Weizu Identification of tobacco smoke mainstream, using solid phase micro-extraction/capillary GC 51st Tobacco Chemists Research Conference, Program Booklet and Abstracts, VoL 51, Paper No. 10, 1997, p. 28. 

This apparent contradiction is best explained by the ensemble behavior of dense mainstream smoke, described by Fuchs (1964). When undiluted mainstream tobacco smoke is passed horizontally into a chamber, the dense smoke column settles as an ensemble, with a gravitational settlement rate equivalent to that for individual particles of 47 /mi diameter. Such behavior can explain the remarkable retention of undiluted smoke (Hinds et al., 1983) as well as the highly nonuniform pattern of deposition for inhaled smoke tars observed by Ermala and Holsti (1955). The heaviest tar deposits occur where the dense smoke column strikes directly on projecting surfaces of the pharynx and the larynx, and at the tracheal and bronchial bifurcations (Er-... 

Reported levels of cyanide in tobacco smoke are quite variable. Cyanide levels in mainstream (inhaled) smoke from U.S. commercial cigarettes have been reported to range from 10 to 400 pg per cigarette, with the ratio of cyanide concentration in sidestream smoke to mainstream smoke ranging from 0.006 to 0.27... 

Tobacco smoke and iV-nitrosation are the focus of intense research activity. Workers in the field use the following concepts Tobacco-specific /V-nitrosamines (TSNA) mainstream tobacco smoke (MSTS), smoke inhaled in a puff sidestream tobacco smoke (SSTS), smoke evolved by smoldering cigarettes between puffs nitroso organic compounds (NOC), referring especially to IV-nitrosamines volatile NOC (VNOC) and iV-nitroso amino acids (NAA). 

Multiple publications (Pankow et al. 1997 Ingebrethsen et al. 2001 Pankow et al. 2003 Watson et al. 2004) have discussed measuring free-base nicotine directly, addressed the importance of free-base nicotine delivery, and examined the chemical properties of nicotine in cigarette smoke as an important determinant of the effective delivery and bioavailability of nicotine from cigarettes. Pankow et al. (1997) examined how ammonia influences nicotine delivery in tobacco smoke and concluded that conversion of nicotine to the free-base form could be facilitated by ammonia. Based on a theoretical treatment, Pankow et al. (1997) concluded that, under certain circumstances, up to 40% of the nicotine could be available as the volatile free-base form. These authors also concluded that the rate of volatilization was more rapid than that previously measured by Lewis et al. (1995) using denuder technology to examine the properties of mainstream cigarette smoke. 

Lewis DA, Colbeck I, Mariner DC (1995) Dilution of mainstream tobacco smoke and its effects upon the evaporation and diffusion of nicotine. J Aerosol Sci 26 841-846... 

Lewis DA, Colbeck I (1996) Modelling of nicotine diffusion from mainstream tobacco smoke within denuder tubes. J Aerosol Sci 27 S319-S320... 

P7 Over the past decade, electron monochromator-mass spectrometry (EM-MS) has been shown to be a selective and sensitive technique for the analysis of a wide variety of electrophilic compounds in complex matrixes. Here, for the hrst time, three different dinitroaniline pesticides, flumetralin, pendimethalin, and trifluralin, have been shown to be present in both mainstream and sidestream tobacco smoke using an EM-MS system. (From Dane et ah, 2006)... 

NT082 Nersessian, A. K., and R. M. Arutyun-yan. The comparative clastogenic activity of mainstream tobacco smoke from cigarettes widely consumed in Armenia. Mutat Res 1994 321(1—2) 89-92. 

The laboratory of the Government Chemist in London undertakes the analysis of tobacco smokes in order to produce league tables (Fig. 20) of the tar and nicotine content of all cigarette brands available in the UK, on behalf of the British government. In this context tar is defined as the total particulate matter present in the main-stream smoke (inhaled smoke), adjusted for its content of water and nicotine alkaloids. Nicotine is defined as the total nicotine-type alkaloids present in the mainstream smoke both are expressed in mg per cigarette. The tar and nicotine league tables are published every six months, and include details of approximately 130 brands of cigarette. 

Smoke drawn through the tobacco and taken in by the smoker is known as mainstream smoke. Smoke which arises from smouldering tobacco and passes directly into the surrounding air, whence it may be inhaled by smokers and nonsmokers alike, is known as sidestream smoke. Mainstream and sidestream smoke differ in composition, partly because of the different temperatures at which they are produced. Substances found in greater concentrations in undiluted sidestream smoke than in undiluted mainstream smoke include nicotine (x 2.7), carbon monoxide (x 2.5), ammonia (x 73),... 

The analysis of tobacco smoke is a subject of numerous studies [51-55], Both mainstream smoke and sidestream smoke are complex mixtures in which about 4000 compounds have been identified [55a], As indicated previously (see Section 3.5) smoke is more complex than tobacco pyrolysate, because besides pyrolysis, some other processes such as combustion, distillation, and aerosol formation occur during smoking. 

Smokers and persons who live in a home with a cigarette smoker also may be exposed to higher levels of formaldehyde. Environmental tobacco smoke, which is a combination of diluted sidestream smoke released from a cigarette s burning end and mainstream smoke exhaled by an active smoker, can contribute 10-25% (0.1-1 mg/day) of the total average indoor exposure to formaldehyde (Fishbein 1992). 

Tobacco smoke exposure is undoubtedly an important risk factor for allergic rhinitis and asthma. However, the precise role of chemicals from smoke on IgE sensitisation is not known, and ftirther studies are necessary. Both active smokers and non-smokers exposed to ETS have been found to be affected adversely. ETS - consisting of mainstream smoke which has been inhaled and exhaled by the primary smoker, and sidestream smoke which arises directly from a burning cigarette - contains many agents that have pathological effects on human tissues [251 (IV), 252(111)]. 

Tricker, A. R., Ditrich, C., and Preussmann, R., V-nitroso compounds in cigarette tobacco and their occurrence in mainstream tobacco smoke. Carcinogenesis, 12, 257-261, 1991. 

---