Tobacco smoke mixtures

The cardiovascular system is adversely impacted by many single chemicals and also by mixtures. The mixtures most toxic to the cardiovascular system are polluted air and tobacco smoke, mixtures for which relationships are so well defined that predictions can be made mathematically on the number of exposed individuals who will be impacted by cardiovascular disease following exposure. 

Environmental Tobacco Smoke (ETS) mixture of smoke from the burning end of a cigarette, pipe, or cigar and smoke exhaled by the smoker (also secondhand smoke or passive smoking). 

Tobacco and its alkaloids have long ceased to have any therapeutic importance, but their extensive use as insecticides and the demand for nicotine for the manufacture of nicotinic acid have stimulated interest in processes of extraction and methods of estimation. On the latter subject there is a voluminous literature, of which critical resumes have been published by various authors.Recent work on this subject has been specially concerned with (1) the development of miero- and semi-miero-methods suitable for estimating nieotine in tobacco smoke and the distribution of nieotine on sprayed garden produce, in treated soils and in tobaeeo leaves,(2) the study of conditions necessary to ensure satisfactory results in using particular processes, " and (3) methods of separation and estimation of nicotine, nomicotine and anabasine in mixtures of these bases. ) In the United States and in Russia considerable interest is being shown in the cultivation of types of tobacco rich in nicotine, in finding new industrial uses for tobacco and its alkaloids, and in possible by-products from tobacco plants such as citric and malic acids, i " Surveys of information on tobacco alkaloids have been published by Jackson, i Marion and Spath and Kuffner. ... 

Environmental tobacco smoke mid gasoline vapors both contain mixtures of trace luiiounts of many of the individual compounds regulated as Air Toxics under Title 111, section 112 of the 1990 Clean Air Act Amendnmts. Much of the general public is more likely to be exposed to these mixtures during the course of their lives tlian to specific compounds on the air toxics list. Hence, estimation of the cancer risk resulting from exposure to these mixtures is a useful and relevant exercise. 

Environmental tobacco smoke (ETS) is the diluted mixture of pollutants caused by smoking of tobacco and emitted into the indoor air by a smoker. Constituents of ETS include submicron-size particles composed of a large number of chemicals, plus a large number of gaseous pollutants. Fibers in indoor air include those of asbestos, and man-made mineral fibers such as fiberglass, and glass wool. 

Human exposure to complex mixtures of polycyclic aromatic hydrocarbons (PAH) occurs through inhalation of tobacco smoke and polluted indoor or outdoor air, through ingestion of certain foods and polluted water, and by dermal contact with soots, tars, and oils CO. Methylated PAH are always components of these mixtures and in some cases, as in tobacco smoke and in emissions from certain fuel processes, their concentrations can be in the same range as some unsubstituted PAH. The estimated emission of methylated PAH from mobile sources in the U.S. in 1979 was approximately 1700 metric tons (2). The occurrence of methylated and unsubstituted PAH has been recently reviewed (1, 2). In addition to their environmental occurrence, methylated PAH are among the most important model compounds in experimental carcinogenesis. 7,12-Dimethylbenz[a]anthracene, one of... 

Some chemical mixtures Tobacco smoke Smokeless tobacco products Soots, tars, mineral oils ... 

For complex mixtures that are readily available for testing as a whole (such as drinking water, diesel exhaust, welding fumes, tobacco smoke, pesticide mixmres, food products) three possible approaches are suggested ... 

The California Air Resources Board has prepared risk assessments for a number of toxic airborne compounds and mixtures, designated as toxic air contaminants, TACs (Table 16.15). For example, risk assessments for individual compounds such as benzene, benzo[a]pyrene (see Chapter 10), formaldehyde, and vinyl chloride have been carried out, in addition to complex mixtures such as diesel exhaust (California Air Resources Board, 1997a) and environmental tobacco smoke (California Environmental Protection Agency, 1997). These risk assessment documents form the basis for controls imposed as part of the risk management process (e.g., see Seiber, 1996). 

For chemicals and complex mixtures of chemicals such as those in some occupational situations or involving cultural habits (e.g. tobacco smoking), the other data considered to be relevant are divided into those on absorption, distribution, metabolism and excretion toxic effects reproductive and developmental effects and genetic and related effects. 

Usage Dark green resin is scraped or extracted form leaves and flower parts and added to tobacco or other smoking mixtures. Dried leaves may also be smoked or chewed. 

Environmental exposures are present through the human lifetime. However, they may vary considerably over time at the same location, for example, because of the local or global changes in emission and environmental pollution levels. Environmental exposures of humans consist of exposures outdoors and indoors as well as at workplaces these environments may significantly differ. The exposure media include air, water, and soil and dust. Historically, research on human exposures to chemicals and associated health effects has been conducted mostly on single chemicals. In addition, several studies have dealt with complex mixtures, such as diesel fuel and gasoline, by-products from coal combustion, and tobacco smoke. A common problem of complex mixtures is that the composition may vary from one exposure to another and, as a result, the associated toxicity may vary. For a better understanding... 

Since 140 in 10 exceeds 80 in 10 . the conclusion is, tliat for identical durations of exposure to identical concenuations in air, enviromnental tobacco smoke poses a greater cancer risk than gasoline vapors. However, both mixtures exliibit liigh cancer risks at trace levels. 

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. 

While many carcinogenicity studies on individual chemicals have been conducted, the study of complex mixtures presents a formidable scientific challenge for the toxicologist. One of the most difficult tasks is related to finding the primary causative agents of the effects. Examples of complex mixtures that have been studied for carcinogenicity include tobacco smoke and diesel engine emissions. 

Environmental criteria have been established for many of these, but the utility and applicability of such criteria for indoor environments is controversial for at least four reasons. Eor example, the goals of the threshold limit values often do not include preventing irritation, a primary concern in indoor environments with requirements for close eye work at video display terminals. For most of the pollutant categories, the problem of interactions, commonly termed the multiple contaminants problem , remains inadequately defined. Even for agents that are thought to affect the same receptor, such as aldehydes, alcohols, and ketones, no prediction models are well established. Finally, the definition of representative compounds for measurement is unclear. That is, pollutants must be measurable, but complex mixtures vary in their composition. It is unclear whether the chronic residual odor annoyance from environmental tobacco smoke correlates better with nicotine, particulates, carbon monoxide, or other pollutants. The measure total volatile organic compounds is meanwhile... 

There are no known direct studies on the toxic effects of chemical exposures on the developing fetus. It is known, however, that children of tobacco smokers (tobacco smoke is a mixture of multiple lipophiles and hydrophiles) have unusually high incidences of ADHD, autism, and other developmental disorders. These and other mixture effects are examined more closely in subsequent chapters. This chapter has aimed to alert the reader to the fact that toxic exposure begins at conception and impacts the fetus throughout gestation and beyond. 

Tobacco smoke. Tobacco smoke produces particulate matter that acts as an adsorption site for toxic vapors)26 In addition to particulates, tobacco smoke produces more than 4000 individual toxic compounds, including 43 known carcinogens. 27 Many of the toxic effects of tobacco smoke that have been established empirically cannot be ascribed to individual compounds in that smoke. With more than 4000 different toxins, the number of mixtures possible is incalculable. Numerous examples of synergism between tobacco smoke and other toxicants have been identified. These include tobacco smoke and asbestos or other mineral fibers, I28 29 alcohol, I30 31 organic solvents, 32 biological... 

Cigarettes, cigars, pipe tobacco, and smokeless tobacco are made up of dried tobacco leaves and hundreds of other components added for flavor and other properties. More than 4000 individual toxic lipophilic and hydrophilic chemical compounds, of which greater than 60 are carcinogens, have been identified in tobacco and tobacco smoke. I35 36 Accordingly, all tobacco and tobacco smoke exposure is, of necessity, to mixtures of toxic chemicals. 

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