Sidestream smoke

The generation of VNA, and especially of NDMA in sidestream smoke (SS) is much higher than that in mainstream smoke (MS). Consequently, VNA levels in SS exceed those in MS up to 50 times (4,9,10 Table II). The possible significance of this observation in respect to indoor air pollution has been discussed by us earlier (12). 

Nonvolatile Nitrosamines In Tobacco Smoke. Although there are more than 10 million exsmokers in the U.S.A., 53 million adults continue to smoke cigarettes and an additional 10 million still smoke cigars or pipes (39). The cigarette smokers are exposed to about 10 ng of volatile nitrosamines, 20-40 ng of NDELA and, most importantly, to 1-10 pg of tobacco specific N-nitros-amines with each cigarette smoked (Table IV). Similar quantities of the TSNA are found in sidestream smoke. The quantities of TSNA in the smoke are dependent on nitrate, nitrite, tobacco alkaloids and on NNN, NNK and NAT in the tobacco itself (31)>... 

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... 

NTl 13 Mohtashamipur, E., A. Mohtashami-pur, P. G. Germann, H. Ernst, K. Norpoth, and U. Mohr. Comparative carcinogenicity of cigarette mainstream and sidestream smoke condensates on the mouse skin. J Cancer Res Clin Oncol 1990 116(6) 604-608. 

The fatal dose of nicotine is approximately 40 mg, or 1 drop of the pure liquid. This is the amount of nicotine in two regular cigarettes. Fortunately, most of the nicotine in cigarettes is destroyed by burning or escapes via the "sidestream" smoke. Ingestion of nicotine insecticides or of tobacco by infants and children is usually followed by vomiting, limiting the amount of the alkaloid absorbed. 

In order to achieve the demanded combination of temporal resolution and accurate yields, FTIR spectroscopy appears a suitable method for collecting data in combination with robust calibrations for quantitative results. Cigarette smoke is known to contain thousands of compounds and the amounts of the vapor phase components in the sidestream smoke are emitted at levels 2-10 times the mainstream amounts [66,67]. In order to utilize vibrational-rotational lines as reported in previous studies [63,64], FT-IR spectra would have to be collected at a spectral resolution of 1 cm 1 or better. Improved temporal resolution of the sidestream concentration profile could only be attained at an equivalent signal-to-noise level by collecting spectra at lower resolution. However, at lower resolution (below 1 cm x) the vibrational-rotational lines would no longer be spectroscopically resolved and accessible to quantification. 

The amount of benzene measured in mainstream smoke ranged from 5.9 to 73 pg/cigarette (Brunnemann et al. 1990). Larger amounts of benzene were found in sidestream smoke, ranging from 345 to 653 pg/cigarette (Brunnemann et al. 1990). 

Brunnemann KD, Kagan MR, Cox JE, et al. 1990. Analysis of 1,3-butadiene and other selected gas-phase components in cigarette mainstream and sidestream smoke by gas chromatography-mass selective detection. Carcinogenesis 11 1863-1868. 

The most frequently cited low probability event, that became apparent as a defense argument for urinalysis, was passive exposure to marijuana smoke. An explanation for a marijuana positive urinalysis was that the service member was exposed to significant quantities of marijuana sidestream smoke in close proximity to the service member. Because this defense may have had validity, the Navy commissioned subsequent scientific studies to resolve this issue. These studies showed conclusively that environmental exposure would result in a marijuana positive, providing the exposure was severe enough. However, in the experiment the exposure needed to be repeated for many hours and at a level such that the subjects needed to wear eye goggles to protect themselves from the marijuana smoke. Exposures at these levels could hardly be considered to be inadvertent or unwilling. As a result of these studies, cutoff levels could be defended and the credibUity of the passive exposure defense was diminished. 

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. 

Brunnemann KD, Masaryk J, Hoffmann D. 1983. Role of tobacco stems in the formation of N-nitrosamines in tobacco and cigarette mainstream and sidestream smoke. J Agric Food Chem 31 1221-1224. 

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)]. 

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