Beitrage zur Tabakforschung International· Volume 17 ·No. 1 · December 1996

Seminars in Science

TOBACCO SMOKE REFERENCES

Tobacco smoke is released from burning tobacco or 1. Newsome, J.R. and C.H. Keith: Variation of the gas tobacco products (, cigars, cigarillos, pipes). phase composition within a burning ; Tob. Without the identification of the exact tobacco product Sci. 9 (1965) 65-69. 2. Dube, M.F. and C.R. Green: Methods of collection and the smoke stream (mainstream smoke, sidestream of smoke for analytical purposes; Recent Adv. Tob. smoke, environmental tobacco smoke) the expression Sci. 8 (1982) 42-102. 'tobacco smoke' is not well defined. In general, tobacco 3. Green, C.R. and A. Rodgman: The Tobacco Chem­ smoke is a dynamic aerosol with particle sizes of 0.01-1.0 ists' Research Conference: A half century forum for p,m. A characteristic property of tobacco smoke is the advances in analytical methodology of tobacco and ageing process, which is the time-related change of its its products; Recent Adv. Tob. Sci. 22 (1996) 131- physical and chemical properties. Special smoke traps or 304.

Table 1. Number of constituents present in tobacco and smoke (2)

Source Number

Tobacco leaf 2549 Unique to leaf 1414 Tobacco smoke 3875 Unique to smoke 2740 Smoke and leaf 1135

I

I machines can be used to collect the total tobacco smoke and distinguish between the particulate and gas phases. Only 20 % of the mass of undiluted to­ bacco smoke is formed by precursors present in tobacco, the remaining 80% of the smoke are gases of atmospheric origin drawn into the cigarette (1). The number of the components qualitatively determined is supposed to be quite similar, quantitatively the differences between the various sources are important. The distribution of com­ pounds in tobacco leaf and smoke is illustrated in Table 1. The total number of components in tobacco smoke is estimated to be much higher. In a recent review the num­ ber of compounds in tobacco and tobacco smoke is esti­ mated to be about 6700 (3).

21 Beitrage zur Tabakforschung International· Volume 17 ·No. 1 ·December 1996

SIDESTREAM SMOKE ponents. Phenols and organic acids have a SS/MS distri­ bution ratio around 1 (5), whereas the SS/MS ratios of the bases are generally larger than 1 (6). The largest mainly consists of the smoke stream SS/MS ratio occurs for ammonia, which is due to the which escapes during smouldering from the burning cone conditions (reducing atmosphere and comparatively low of the cigarettes or other tobacco products. A diffusion temperature) at sidestream smoke formation. An in­ stream which is formed during the puffs at the burning creased level of ammonia is probably the major cause for end and diffuses through the cigarette paper into the the higher pH of sidestream smoke compared to main- · surrounding air as well as a smouldering stream formed stream smoke. at the mouth end during the smoulder period make a The characteristic properties and the composition of the minor contribution to the formation of sidestream cigarette paper have an important influence on side­ smoke (Figure. 1). stream smoke yields. An increase in the number of paper layers, increased paper weight, and decreased filter poros­ Figure 1. ity lead to a reduction in the yield of sidestream smoke Schematic representation of the smoke streams of a components. Anorganic paper fillers, such as (Mg(OH) 2,

cigarette (1 ,2) Al(OHt MgC03, CaC03), additives to the paper which influence the burning rate (Na+/K-- salts of carbonic acids) as well as ash conditioners (NaCl, KCl) also signifi­ Smoke stream cantly influence sidestream smoke yields. ~ Diffusion stream &) rr rn rrr ~:~:::"' <_>I, ------'-""~~....,-c'=:':,-"'~;;:=·;{"-=.;Ol ::::::. period) ~- ~~cc;~r...,~ Mainstream REFERENCES (Puffing)

1. Lipp, G.: Zur Definition der Selektivitat unci der Although mainstream smoke and sidestream smoke are verschiedenen Rauchstrome der Cigarette; Beitr. largely composed of the same components, their physical Tabakforsch. 3 (1965/66) 220-222. and chemical properties vary widely. This is mainly due 2. Klus, H. and H. Kuhn: Verteilung verschiedener to the different formation mechanisms. Radioactive label­ Tabakrauchbestandteile auf Haupt- unci Neben­ ling of compounds in the cigarette rod has shown that stromrauch (Eine Ubersicht); Beitr. Tabakforsch. Int. the central portion of the cigarette rod mainly contrib­ 11 (1982) 229-265. utes to the sidestream gas phase (3) . 3. Jenkins, R.W., T.R. Bass, R.H. Newman and M. K. In contrast to the determination of cigarette mainstream Chavis: Cigarette smoke formation studies V. The smoke yields, no official standard methods exist for the effects of the cigarette periphery on mainstream determination of sidestream smoke yields. Special cham­ smoke formation; Beitr. Tabakforsch. 9 (1977-78) bers have been developed to collect sidestream smoke for 126-130. chemical analysis (2,4). The conditions in the small exper­ 4. Dube, M.F. and C.R. Green: Methods of collection imental chambers with respect to temperature, humidity of smoke for analytical purposes; Recent Adv. Tab. and concentrations may lead to the generation of an arti­ Sci. 8 (1982) 42-102. ficially composed sidestream smoke. This problem can be 5. Sakuma, H., M. Kusama, S. Munakata, T. Ohsumi avoided by analyzing sidestream smoke in bigger experi­ and S. Sugawara: The distribution of cigarette smoke mental chambers or rooms. components between mainstream and sidestream In Table 1, mainstream smoke yields as well as sidestream smoke - I. Acidic components; Beitr. Tabakforsch. smoke to mainstream smoke yield ratios (SS/MS) of se­ Int. 12 (1983-84) 63-71. lected compounds of nonfilter cigarettes are shown. A 6. Sakuma, H., M. Kusama, K. Yamaguchi, T. Matsuki distinction is made between vapour phase and particulate and S. Sugawara: The distribution of cigarette smoke phase constituents. The sidestream smoke to mainstream components between mainstream and sidestream smoke ratios vary between 0.1 to 170 which is due to the smoke - II. Bases; Beitr. Tabakforsch. Int. 12 (1983- different formation processes of individual smoke cam- 84) 199-209.

22 Table 1. Concentrations of selected compounds in nonfilter cigarette mainstream smoke and the ratio of their relative distribution in sidestream smoke (SS: MS) (7)

Compound MS SS:MS

Vapour phase

Carbon monoxide 10-23 mg 2.5 - 4.7 Carbon dioxide 20-60 mg 8 - 11 Carbonyl sulphide 18-42~g 0.03-0.13 Benzene 12-48~g 10 Toluene 160 ~g 6-8 Formaldehyde 70- 100 ~g 0.1 - 50 Acrolein 60 - 100 ~g 8- 15 Acetone 100 - 250 ~g 2-5 Pyridine 16- 40 ~g 7 - 20 3-Vinylpyridine 15- 30 ~g 20-40 Hydrogen cyanide 400-500 ~g 0.1-0.25 Hydrazine 32 ng 3.0 Ammonia 50- 150 ~g 40- 170 Methylamine 17.5-28.7 ~g 4.2- 6.4 Dimethylamine 7.8-10~g 3.7-5.1 Nitrogen oxides 100- 600 ~g 4- 10 N-Nitrosodimethylamine 10 - 40 ng 20- 100 N-Nitrosopyrrolidine 6- 30 ng 6-30 Formic acid 210-478 ~g 1.4- 1.6 Acetic acid 330-810 ~g 1.9 - 3.9

Particulate phase

Particulate matter 15-40 mg 1.3 - 1.9 Nicotine 1.7-3.3 mg 1.8 - 3.3 Anatabine 2.4-20.1 ~g 0.1 - 0.5 Phenol 60- 140 ~g 1.6 - 3.0 Catechol 100- 360 ~g 0.6- 0.9 Hydroquinone 110- 300 ~g 0.7 - 0.9 An iline 360 ng 30 ortho-Toluidine 160 ng 19 2-Naphthylamine 1.7 ng 30 4-Aminobiphenyl 4.6 ng 31 Benz[a]anthracene 20-70 ng 2.2-4 Benzo[a]pyrene 20-40 ng 2.5- 3.5 Cholesterol 14.2 ~g 0.9 y-Butyrolactone 10- 22 ~g 3.6- 5.0 Quinoline 0.5- 2 ~g 8 - 11 Harman 1.7-3.1 ~g 0.7 - 1.9 N '-Nitrosonornicotine 0.2-0.3 ~g 0.5-3 4-(Methylnitrosamino )-1- (3-pyridyl)-1-butanone 0.1 - 1 ~g 1 - 4 N-Nitrosodiethanolamine 20-70 ng 1.2 Cadmium 100 ng 3.6- 7.2 Nickel 20- 80 ng 0.2- 30 Zinc 60 ng 0.2- 6.7 Polonium-21 0 0.03 - 0.5 pCi 1.06- 3.7 Benzoic acid 14-28 ~g 0.67- 0.95 Lactic acid 63-174 ~g 0.5- 0.7 Glycolic acid 37-126 ~g 0.6- 0.95 Succinic acid 112 - 163 ~g 0.43- 0.62

23 7. IARC Monographs: ; Vol. 38, Lyon: International Agency for Research on Cancer, Lyon, 1986. 8. Guerin, M.R.: Formation and physicochemical na­ ture of sidestream smoke; in: Environmental carcino­ gens methods of analysis and exposure measurement, Vol. 9: , edited by I.K. O'Neill, K.D. Brunnemann, B. Dodet and D. Hoffmann, IARC Scientific Publications No. 81, International Agency for Research on Cancer, Lyon, 1987, pp. 11-23 .

24 Beitrage zur Tabakforschung International· Volume 17 ·No. 1 ·December 1996

MAINSTREAM SMOKE Mainstream smoke is a concentrated aerosol formed of liquid particles, whose retention through the different Mainstream smoke is the fraction of tobacco smoke smoke traps leads to the smoke condensate. The non­ which is generated during puff-drawing in the burning condensed part that remains is the gaseous phase. In cone of a cigarette, cigar or pipe and is inhaled by the Table 1, some physicochemical properties of mainstream smoker via the filter tip. During machine-smoking of smoke are compared to sidestream smoke. cigarettes for smoke analysis, the mainstream smoke is collected according to standardized conditions.Thereby The material balance of mainstream cigarette smoke can be calculated as follows (1): approximately 55 mm tobacco rod (equivalent to 800 mg tobacco) are burnt, from which 300 mg of tobacco are burnt for the generation of mainstream smoke and Mainstream (TPM and gas phase) weight = weight of cigarette burned during puffs approximatively 500 mg for sidestream smoke formation. + mainstream combustion oxygen weight The mainstream smoke is formed by numerous mecha­ + mainstream entrained gas weight nisms and reactions taking place in the different regions - weight of ash produced during puffs. inside a cigarette. During the puffs, the temperature in the burning cone reaches approximately 900°C (smoul­ For the unfiltered cigarette, the total mainstream smoke dering temperature between the puffs: approximately effluent to be measured is about 500 mg/cig. The ciga­ 600°C). The high temperature zone (600°C - 900°C) is rette mainstream smoke components obtained from an almost completely free of oxygen and contains approxi­ unfiltered 85 mm cigarette smoked under standard condi­ mately 8 volume-% oxygen and 15 volume-% carbon tions are presented in Table 2. monoxide. The succeeding zones (in the direction of puff-drawing) are the pyrolysis-distillation zone (100°C - 600°C) and the low temperature zone ( < 100°C). Twelve The composition of mainstream smoke determines its volume-% of the oxygen are formed in the low tempera­ organoleptic and biological properties. It is influenced by ture zone. In these zones, the mainstream smoke aerosol numerous factors such as e.g. tobacco variety, tobacco is formed by pyrolysis, hydrogenisation, oxidation, blend, cutting width, humidity, density, additives, paper ~ecarboxylation, dehydration, condensation, distillation, porosity, filtration and ventilation. The composition of sublimation and filtration of tobacco constituents. The mainstream smoke also depends on the smoking profile smoke aeorosol is diluted during the time of travel (puff duration, puff interval, puff volume, puff profile) as through the cigarette tube to the mouth piece by air well as number of puffs if the smoke analysis is made drawn into the cigarette through the pores in the paper after each puff. The last factors are standardized in the and around the burning zone. At the mouth piece the smoking conditions (machine smoking). They are only mainstream smoke has a temperature between 25 - 50°C determinant in human smoking behaviour. depending of the butt lenght.

Table 1. Physicochemical properties of mainstream smoke compared to sidestream smoke.

Smoke characteristics Mainstream smoke Sidestream smoke

Formation period (s/cig.) 20 550 Amount of tobacco burned (mg/cig.) about300 about500 Temperature of formation (0 C) about900 about 600 Total particulate matter (mg/cig.) about15 about25 Nicotine (mg/cig.) about1 about 3 Particle size (~m) 0.1- 1.0 0.01 - 0.8 pH 5.8 - 6.2 6.7 - 8.0

25 Table 2. Material balance of cigarette smoke, 85 mm unfiltered cigarettes (1 0 puffs of 38.9 ml volume, 30 mm butt lenght) (2)

Weight Weight Material mg/cig percent of total effluent

Particulate matter (inc. cond. H20) 40.6 8.2 Nitrogen (67.2 volume%) 295.4 59 .0 Oxygen (13.3 volume %) 66.8 13.4 Carbon dioxide (9 .8 volume %) 68.1 13.6 Carbon monoxide (3.7 volume %) 16.2 3.2 Hydrogen (2.2 volume %) 0.7 0.1 Argon (0.8 volume %) 5.0 1.0 Methane (0.5 volume %) 1.3 0.3 Water vapor (rei. hum. = 60 %) 5.8 1.2

C2 - C6 Hydrocarbons 2.5 0.5 Carbonyls 1.9 0.4 Hydrogen cyanide 0.3 0.1 Other known gaseous materials 1.0 0.2

Total 505.6 101 .2 Measured Total Effluent 500 100

REFERENCES

1. Gori, G. B.: Approaches to the reduction of total particulate matter (TPM) in cigarette smoke; in Pro­ ceedings of the Third World Conference on Smok­ ing and Health, edited by E. L. Wynder, D. Hoffmann and G. B. Gori, U.S. Department of Health, Education, and Welfare, DHEW Publication No. (NIH) 76-1221, pp. 451-461. 2. Keith C.H. and P.G. Tesh: Measurement of the total smoke issuing from a burning cigarette; Tab. Sci. 9 (1965) 61 -64. 3. Eatough, D., L.D. Hansen and E.A. Lewis: The chemical characterization of environmental tobacco smoke; in Proceedings of the International Sympo­ sium at McGill University 1989, edited by D.J. Eco­ bichon and J.M.Wu, Lexington Books, Lexington, Massachusetts, 1990, pp. 3-39.

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