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    Smoke

    Smoke

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    This article is about the collection of airborne particulates and gases. For the practice of smoking, see Smoking. For other uses, see Smoke (disambiguation).

    It has been suggested that be merged into this article. (Discuss)

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    "Smoke" – news · newspapers · books · scholar · JSTOR

    Smoke from a fire

    Smoke from a bee smoker, used in beekeeping

    Chemical composition distribution of volatile organic compounds released in smoke from a variety of solid fuels[1]

    Volatility distribution of volatile organic compound emissions in wood smoke[2]

    Smoke being emitted from a lit cigarette

    Oil fires and smoke, after Iraqi forces set fire to oil wells during the First Gulf War

    Smoke is a collection of airborne particulates and gases[3] emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product of fires (including stoves, candles, internal combustion engines, oil lamps, and fireplaces), but may also be used for pest control (fumigation), communication (smoke signals), defensive and offensive capabilities in the military (smoke screen), cooking, or smoking (tobacco, cannabis, etc.). It is used in rituals where incense, sage, or resin is burned to produce a smell for spiritual or magical purposes. It can also be a flavoring agent and preservative.

    Smoke from a grassland fire in Northern Mexico during a heat wave occurring at the same time as the forest fire season in Mexico.

    Smoke inhalation is the primary cause of death in victims of indoor fires. The smoke kills by a combination of thermal damage, poisoning and pulmonary irritation caused by carbon monoxide, hydrogen cyanide and other combustion products.

    Smoke is an aerosol (or mist) of solid particles and liquid droplets that are close to the ideal range of sizes for Mie scattering of visible light.[4]

    Contents

    1 Chemical composition

    1.1 Visible and invisible particles of combustion

    2 Dangers 2.1 Corrosion

    2.2 Health effects of wood smoke

    3 Measurement 4 Medicinal smoking 5 References 6 Sources 7 External links

    Chemical composition[edit]

    The composition of smoke depends on the nature of the burning fuel and the conditions of combustion. Fires with high availability of oxygen burn at a high temperature and with a small amount of smoke produced; the particles are mostly composed of ash, or with large temperature differences, of condensed aerosol of water. High temperature also leads to production of nitrogen oxides.[5] Sulfur content yields sulfur dioxide, or in case of incomplete combustion, hydrogen sulfide.[6] Carbon and hydrogen are almost completely oxidized to carbon dioxide and water.[7] Fires burning with lack of oxygen produce a significantly wider palette of compounds, many of them toxic.[7] Partial oxidation of carbon produces carbon monoxide, while nitrogen-containing materials can yield hydrogen cyanide, ammonia, and nitrogen oxides.[8] Hydrogen gas can be produced instead of water.[8] Contents of halogens such as chlorine (e.g. in polyvinyl chloride or brominated flame retardants) may lead to the production of hydrogen chloride, phosgene, dioxin, and chloromethane, bromomethane and other halocarbons.[8][9] Hydrogen fluoride can be formed from fluorocarbons, whether fluoropolymers subjected to fire or halocarbon fire suppression agents. Phosphorus and antimony oxides and their reaction products can be formed from some fire retardant additives, increasing smoke toxicity and corrosivity.[9] Pyrolysis of polychlorinated biphenyls (PCB), e.g. from burning older transformer oil, and to lower degree also of other chlorine-containing materials, can produce 2,3,7,8-tetrachlorodibenzodioxin, a potent carcinogen, and other polychlorinated dibenzodioxins.[9] Pyrolysis of fluoropolymers, e.g. teflon, in presence of oxygen yields carbonyl fluoride (which hydrolyzes readily to HF and CO2); other compounds may be formed as well, e.g. carbon tetrafluoride, hexafluoropropylene, and highly toxic perfluoroisobutene (PFIB).[10]

    स्रोत : en.wikipedia.org

    Harms of Cigarette Smoking and Health Benefits of Quitting

    A fact sheet that lists some of the cancer-causing chemicals in tobacco smoke and describes the health problems caused by cigarette smoking and the benefits of quitting.

    Harms of Cigarette Smoking and Health Benefits of Quitting

    What harmful chemicals does tobacco smoke contain?

    What are some of the health problems caused by cigarette smoking?

    What are the risks of tobacco smoke to nonsmokers?

    Is smoking addictive?

    Are other tobacco products, such as smokeless tobacco or pipe tobacco, harmful and addictive?

    Is it harmful to smoke just a few cigarettes a day?

    What are the immediate health benefits of quitting smoking?

    What are the long-term health benefits of quitting smoking?

    Does quitting smoking lower the risk of getting and dying from cancer?

    Is it important for someone diagnosed with cancer to quit smoking?

    Where can I get help to quit smoking?

    स्रोत : www.cancer.gov

    Chemistry and Toxicology of Cigarette Smoke and Biomarkers of Exposure and Harm

    This chapter summarizes the state of knowledge about the chemistry and toxicology of cigarette smoke and provides data relevant to the evaluations and conclusions presented in the disease-specific chapters of this report. The literature reviewed in this chapter is limited to manufactured cigarettes and does not include publications on handmade (“roll your own”) cigarettes or other products that contain nicotine. The next section, “Chemistry,” includes a brief description of technologies used by cigarette manufacturers in a limited number of cigarette brands marketed as “reduced-exposure” or “lower-yield” products. These commercial products have not been met with widespread consumer acceptance. The following section, “Biomarkers,” focuses on the manufactured tobacco-burning cigarette consumed by the majority of smokers in the United States and elsewhere.

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    How Tobacco Smoke Causes Disease: The Biology and Behavioral Basis for Smoking-Attributable Disease: A Report of the Surgeon General.

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    3Chemistry and Toxicology of Cigarette Smoke and Biomarkers of Exposure and Harm

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    Introduction

    This chapter summarizes the state of knowledge about the chemistry and toxicology of cigarette smoke and provides data relevant to the evaluations and conclusions presented in the disease-specific chapters of this report. The literature reviewed in this chapter is limited to manufactured cigarettes and does not include publications on handmade (“roll your own”) cigarettes or other products that contain nicotine. The next section, “Chemistry,” includes a brief description of technologies used by cigarette manufacturers in a limited number of cigarette brands marketed as “reduced-exposure” or “lower-yield” products. These commercial products have not been met with widespread consumer acceptance. The following section, “Biomarkers,” focuses on the manufactured tobacco-burning cigarette consumed by the majority of smokers in the United States and elsewhere.

    The section on “Chemistry” describes the chemical components of cigarette smoke and addresses aspects of product design that alter the components of cigarette smoke and factors affecting delivery of smoke to the smoker. In most cases, the data reported for chemical levels in mainstream smoke were derived under standard smoking conditions described by the U.S. Federal Trade Commission (FTC) and the International Organization for Standardization (ISO). These standard conditions are puff volume of 35 milliliters (mL), two-second puff duration, one-minute puff frequency, and butt length defined as either 23 millimeters (mm) for nonfilter cigarettes or the length of the filter overwrap paper plus 3 mm. When alternative smoking regimens are used, levels of potentially harmful substances in smoke emissions usually differ from those measured under standard conditions. (For more details, see “Delivery of Chemical Constituents into Tobacco Smoke” later in this chapter.) When people smoke, they do not use the puff volume and puff frequency programmed into smoking machines, and smoking habits vary significantly from person to person and cigarette to cigarette. Consequently, actual exposures to and doses of components of smoke cannot be derived from values obtained with machine smoking.

    The section on “Biomarkers” offers an overview of in vitro and in vivo data on genotoxicity and cytotoxicity and a review of the literature on animal bioassays, in addition to general concepts of biomarkers of exposure, of biologically effective dose, and of potential harm, as an introduction to more detailed descriptions of biomarkers in subsequent chapters of this Surgeon General’s report.

    Cigarette smoke is a complex mixture of chemical compounds that are bound to aerosol particles or are free in the gas phase. Chemical compounds in tobacco can be distilled into smoke or can react to form other constituents that are then distilled to smoke. Researchers have estimated that cigarette smoke has 7,357 chemical compounds from many different classes (Rodgman and Perfetti 2009). In assessing the nature of tobacco smoke, scientists must consider chemical composition, concentrations of components, particle size, and particle charge (Dube and Green 1982). These characteristics vary with the cigarette design and the chemical nature of the product.

    Fowles and Dybing (2003) suggested an approach to identify the chemical components in tobacco smoke with the greatest potential for toxic effects. They considered the risk for cancer, cardiovascular disease, and heart disease. Using this approach, these investigators found that 1,3-butadiene presented by far the most significant cancer risk; acrolein and acetaldehyde had the greatest potential to be respiratory irritants; and cyanide, arsenic, and the cresols were the primary sources of cardiovascular risk. Other chemical classes of concern include other metals, -nitrosamines, and polycyclic aromatic hydrocarbons (PAHs). This evaluation, along with the Hoffmann list of biologically active chemicals (Hoffmann and Hoffmann 1998), was used to select the chemicals reviewed in this chapter. Other chemical components with potential for harm will be identified as analysis of tobacco smoke becomes more complete and cigarette design and additives change.

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    Chemistry

    Phases of Tobacco Smoke

    Smoke from a burning cigarette is a “concentrated aerosol of liquid particles suspended in an atmosphere consisting mainly of nitrogen, oxygen, carbon monoxide and carbon dioxide” (Guerin 1980, p. 201). Researchers have also described cigarette smoke as a “lightly charged, highly concentrated matrix of submicron particles contained in a gas with each particle being a multicompositional collection of compounds arising from distillation, pyrolysis, and combustion of tobacco” (Dube and Green 1982, p. 42). Tobacco smoke is a complex and dynamic chemical mixture. Researchers have analyzed whole smoke or used chemical and physical means to separately examine the gas and particulate portions of tobacco smoke. The gas phase is defined as the portion of smoke that passes through a glass fiber filter of specified physical parameters, and the particulate phase refers to all matter captured by the glass fiber filter (Pillsbury 1969). Standard methods for analysis of tobacco smoke separate the two phases by using Cambridge glass fiber filters designed to collect aerosol particles of 0.3 micrometers (μm) or larger with an efficiency not less than 99 percent (Pillsbury 1969). Although these separate phases are an artificial construct, they are useful for describing the results of analysis of the components of cigarette smoke typically obtained by machine smoking. When people smoke cigarettes, the continuum of physical characteristics in smoke does not include the differentiation into specific fractions. The diameter of cigarette smoke particles constantly changes, and as the particles coalesce after their formation, they grow in diameter. However, in diluted smoke, loss of a volatile chemical matrix or other components may cause particles to shrink and changes in the particle size may alter the relative amounts of certain chemicals in the gas and particle phases (Guerin 1980).

    स्रोत : www.ncbi.nlm.nih.gov

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