Sidestream smoke

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Sidestream smoke in enclosed box. Sidestream Smoke 2010.jpg
Sidestream smoke in enclosed box.

Sidestream smoke is smoke which goes into the air directly from a burning cigarette, cigar, or smoking pipe. [1] Sidestream smoke is the main component (around 85%) of second-hand smoke (SHS), also known as Environmental Tobacco Smoke (ETS) or passive smoking. [2] The chemical constituents of sidestream smoke are different from those of directly inhaled ("mainstream") smoke. Sidestream smoke has been classified as a Class A carcinogen by the U.S. Environmental Protection Agency.

Smoke mass of airborne particulates and gases

Smoke is a collection of airborne solid and liquid particulates and gases 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, but may also be used for pest control (fumigation), communication, defensive and offensive capabilities in the military, cooking, or smoking. It is used in rituals where incense, sage, or resin is burned to produce a smell for spiritual purposes. Smoke is sometimes used as a flavoring agent, and preservative for various foodstuffs. Smoke is also a component of internal combustion engine exhaust gas, particularly diesel exhaust.

Cigarette small roll of cut tobacco designed to be smoked

A cigarette is a narrow cylinder containing psychoactive material, usually tobacco, that is rolled into thin paper for smoking. Most cigarettes contain a "reconstituted tobacco" product known as "sheet", which consists of "recycled [tobacco] stems, stalks, scraps, collected dust, and floor sweepings", to which are added glue, chemicals and fillers; the product is then sprayed with nicotine that was extracted from the tobacco scraps, and shaped into curls. The cigarette is ignited at one end, causing it to smolder and allowing smoke to be inhaled from the other end, which is held in or to the mouth. Most modern cigarettes are filtered, although this does not make them safer. Cigarette manufacturers have described cigarettes as a drug administration system for the delivery of nicotine in acceptable and attractive form. Cigarettes are addictive and cause cancer, chronic obstructive pulmonary disease, heart disease, and other health problems.

Passive smoking inhalation of smoke by persons other than the intended active smoker

Passive smoking is the inhalation of smoke, called second-hand smoke (SHS), or environmental tobacco smoke (ETS), by persons other than the intended "active" smoker. It occurs when tobacco smoke permeates any environment, causing its inhalation by people within that environment. Exposure to second-hand tobacco smoke causes disease, disability, and death. The health risks of second-hand smoke are a matter of scientific consensus. These risks have been a major motivation for smoke-free laws in workplaces and indoor public places, including restaurants, bars and night clubs, as well as some open public spaces.



Like mainstream smoke, sidestream tobacco smoke is made up of many components including carbon monoxide, tar, nicotine, ammonia, benzene, cadmium and 4-aminobiphenyl. [3] [4] [5] Some of the other compounds found in sidestream smoke are: vinylchloride, hydrogen cyanide, arsenic, acrolein, acetaldehyde, formaldehyde, catechol, cresol, hydroquinone, lead, methyl ethyl ketone, nitric oxide, phenol, styrene, toluene, and butane. Exposure to sidestream smoke yields higher concentrations of these compounds as well as increased concentrations of carboxyhemoglobin, nicotine, and cotinine in the blood. When comparing sidestream and mainstream condensate, sidestream has 2–6 times more condensate per gram than mainstream smoke. [3] [4] [5] Due to the incomplete combustion process responsible for the creation of sidestream smoke, there may be exposure to higher concentrations of carcinogens than are typically inhaled directly.

Carbon monoxide chemical compound

Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is slightly less dense than air. It is toxic to animals that use hemoglobin as an oxygen carrier when encountered in concentrations above about 35 ppm, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal biological functions. In the atmosphere, it is spatially variable and short lived, having a role in the formation of ground-level ozone.

Tar substance

Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. Production and trade in pine-derived tar was a major contributor in the economies of Northern Europe and Colonial America. Its main use was in preserving wooden sailing vessels against rot. The largest user was the Royal Navy. Demand for tar declined with the advent of iron and steel ships.

Nicotine group of stereoisomers

Nicotine is a stimulant and potent parasympathomimetic alkaloid that is naturally produced in the nightshade family of plants and used for the treatment of tobacco use disorders as a smoking cessation aid and nicotine dependence for the relief of withdrawal symptoms. Nicotine acts as a receptor agonist at most nicotinic acetylcholine receptors (nAChRs), except at two nicotinic receptor subunits where it acts as a receptor antagonist.


There are over 250 toxins and carcinogens in cigarette smoke. The risks of developing lung cancer, brain tumors, and acute myeloid leukemia and the incidence of heart disease and benign respiratory diseases increase with the inhalation of sidestream smoke. [6] Additionally, the chance of developing breast cancer and cervical cancer also increases with the inhalation of sidestream smoke.

Lung cancer cancer in the lung

Lung cancer, also known as lung carcinoma, is a malignant lung tumor characterized by uncontrolled cell growth in tissues of the lung. This growth can spread beyond the lung by the process of metastasis into nearby tissue or other parts of the body. Most cancers that start in the lung, known as primary lung cancers, are carcinomas. The two main types are small-cell lung carcinoma (SCLC) and non-small-cell lung carcinoma (NSCLC). The most common symptoms are coughing, weight loss, shortness of breath, and chest pains.

Brain tumor type of tumor

A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant or cancerous tumors and benign tumors. Cancerous tumors can be divided into primary tumors, which start within the brain, and secondary tumors, which have spread from elsewhere, known as brain metastasis tumors. All types of brain tumors may produce symptoms that vary depending on the part of the brain involved. These symptoms may include headaches, seizures, problems with vision, vomiting and mental changes. The headache is classically worse in the morning and goes away with vomiting. Other symptoms may include difficulty walking, speaking or with sensations. As the disease progresses, unconsciousness may occur.

Leukemia group of cancers that usually begin in the bone marrow

Leukemia, also spelled leukaemia, is a group of cancers that usually begin in the bone marrow and result in high numbers of abnormal white blood cells. These white blood cells are not fully developed and are called blasts or leukemia cells. Symptoms may include bleeding and bruising problems, feeling tired, fever, and an increased risk of infections. These symptoms occur due to a lack of normal blood cells. Diagnosis is typically made by blood tests or bone marrow biopsy.

Evidence has shown that sidestream smoke may be more harmful, per gram, than mainstream smoke. [7] However, sidesmoke is inhaled in far lesser amounts than in people who smoke tobacco.

The relative risk of cardiovascular disease is 1.2–1.3 with exposure to sidestream smoke due the cyanide present in the smoke. There is also evidence that sidestream smoke causes negative effects in children, both behaviorally and cognitively. One study found that higher levels of cotinine in children were correlated with a decreased ability to perform in reading and math. [3] [8]

Cardiovascular disease class of diseases that involve the heart or blood vessels

Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction. Other CVDs include stroke, heart failure, hypertensive heart disease, rheumatic heart disease, cardiomyopathy, heart arrhythmia, congenital heart disease, valvular heart disease, carditis, aortic aneurysms, peripheral artery disease, thromboembolic disease, and venous thrombosis.

Factors such as age, gender and different occupations put a person at risk for bladder cancer - smoking is the only other known risk. 4-aminobiphenyl (4-ABP) is an integral component in tobacco smoke, as well as a risk factor for bladder cancer. Sidestream smoke puts individuals at an increased risk of bladder cancer because the 4-ABP concentrations are over ten times that of mainstream smoke. [9] [10]

Bladder cancer urinary system cancer that results in malignant growth located in the urinary bladder

Bladder cancer is any of several types of cancer arising from the tissues of the urinary bladder. It is a disease in which cells grow abnormally and have the potential to spread to other parts of the body. Symptoms include blood in the urine, pain with urination, and low back pain.

Social effects

A non-smoker who is inhaling sidestream or second-hand smoke has a 30% greater risk of getting lung cancer at some point in their lives. [11] Exposure to second hand or sidestream smoke has been associated with people who have not smoked before.

The US Environmental Protection Agency estimates sidestream smoke causes approximately 3,000 lung cancer deaths and 62,000 deaths from heart disease in non-smokers every year in the United States. [12]


A child's exposure to contaminants in the air can have detrimental health effects including heightened risk of respiratory tract infections, increased likelihood of childhood asthma, behavioural problems and reduced neurocognitive abilities. Exposure to mainstream and sidestream smoke in childhood poses an increased risk of coughing, wheezing, and mucus production. Studies on rats have shown that those who were exposed to sidestream smoke while in utero and following the period directly after, had differences in airway sensitivity in comparison to those that had been exposed to sidestream smoke only while in utero or only following the period after. [13] [14] [15]

Test tubes

A reduction in glutathione levels was observed following exposure to sidestream smoke in vitro. Glutathione is an antioxidant which resides in the lung after development. Exposure to sidestream smoke for as little as twenty minutes can lead to an increase in contaminant particles within human small airway epithelial cells (SAEC). Cells exposed to sidestream smoke experienced oxidative stress, which further allowed for DNA damage as well as cell transformation and an uncontrolled cell proliferation. Such DNA mutations and uncontrolled cell division resulting from exposure to sidestream smoke may result in cancerous tumours. [16] [17]

Toxicological experiments

During the 1980s the Philip Morris Tobacco Company carried out research on sidestream smoke at the Institut für Biologische Forschung, although this was not voluntarily published. This study found that sidestream smoke is nearly four times more toxic than mainstream smoke per metric gramme. They also found that sidestream condensate was nearly three times more toxic than mainstream smoke as well as 2–6 times more tumourigenic per gram than mainstream condensate when applied to the skin of a mouse; results also showed that sidestream smoke hinders an animal's ability to reach a weight that is considered normal. The research team concluded that the only way to protect oneself from sidestream smoke was to be in smoke-free public places and workspaces. [7]

Related Research Articles

A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis, the formation of cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive substances are considered carcinogens, but their carcinogenic activity is attributed to the radiation, for example gamma rays and alpha particles, which they emit. Common examples of non-radioactive carcinogens are inhaled asbestos, certain dioxins, and tobacco smoke. Although the public generally associates carcinogenicity with synthetic chemicals, it is equally likely to arise in both natural and synthetic substances. Carcinogens are not necessarily immediately toxic; thus, their effect can be insidious.

Cigarette smoke is an aerosol produced by the incomplete combustion of tobacco during the smoking of cigarettes. Temperatures in burning cigarettes range from about 400 ℃ between puffs to about 900 ℃ during a puff. During the burning of the cigarette tobacco, thousands of chemical substances are generated by combustion, distillation, pyrolysis and pyrosynthesis. Tobacco smoke is used as a fumigant and inhalant.

Tobacco smoking practice of burning tobacco and inhaling the resulting smoke

Tobacco smoking is the practice of smoking tobacco and inhaling tobacco smoke. The practice is believed to have begun as early as 5000–3000 BC in Mesoamerica and South America. Tobacco was introduced to Eurasia in the late 17th century by European colonists, where it followed common trade routes. The practice encountered criticism from its first import into the Western world onwards but embedded itself in certain strata of a number of societies before becoming widespread upon the introduction of automated cigarette-rolling apparatus.

Cotinine chemical compound

Cotinine is an alkaloid found in tobacco and is also the predominant metabolite of nicotine. Cotinine is used as a biomarker for exposure to tobacco smoke. Cotinine is currently being studied as a treatment for depression, PTSD, schizophrenia, Alzheimer's disease and Parkinson's disease. Cotinine was developed as an antidepressant as a fumaric acid salt, cotinine fumarate, to be sold under the brand name Scotine but it was never marketed.

Tar is the common name for the resinous, partially combusted particulate matter produced by the burning of tobacco and other plant material in the act of smoking. Tar is toxic and damages the smoker's lungs over time through various biochemical and mechanical processes. Tar also damages the mouth by rotting and blackening teeth, damaging gums, and desensitizing taste buds. Tar includes the majority of mutagenic and carcinogenic agents in tobacco smoke. Polycyclic aromatic hydrocarbons (PAH), for example, are genotoxic via epoxidation.

Health effects of tobacco circumstances, mechanisms, and factors of tobacco consumption on human health

Tobacco use has predominantly negative effects on human health and concern about health effects of tobacco has a long history. Research has focused primarily on cigarette tobacco smoking.

Occupational lung diseases are occupational, or work-related, lung conditions that have been caused or made worse by the materials a person is exposed to within the workplace. It includes a broad group of diseases, including occupational asthma, chronic obstructive pulmonary disease (COPD), bronchiolitis obliterans, inhalation injury, interstitial lung diseases, infections, lung cancer and mesothelioma. These diseases can be caused directly or due to immunological response to a exposure to a variety of dusts, chemicals, proteins or organisms.

Herbal cigarette

Herbal cigarettes are cigarettes that usually do not contain any tobacco, instead being composed of a mixture of various herbs and/or other plant material. However, Chinese herbal cigarettes contain tobacco and nicotine with herbs added, unlike European and North American herbal cigarettes which have tobacco and nicotine omitted. Like herbal smokeless tobacco, they are often used as a substitute for standard tobacco products. Herbal cigarettes are considered a "non-smoking aid." European countries advertise herbal cigarettes as a cessation smoking aid. Herbal cigarettes are also used in acting scenes by performers who are non-smokers, or—as is becoming increasingly common—where anti-smoking legislation prohibits the use of tobacco in public spaces. Herbal cigarettes can carry carcinogens which can have health implications.

4-Aminobiphenyl (4-APB) is an organic compound with the formula C6H5C6H4NH2. It is an amine derivative of biphenyl. It is a colorless solid, although aged samples can appear colored. 4-Aminobiphenyl was commonly used in the past as a rubber antioxidant and an intermediate for dyes. Exposure to this aryl-amine can happen through contact with chemical dyes and from inhalation of cigarette smoke. Researches showed that 4-aminobiphenyl is responsible for bladder cancer in humans and dogs by damaging DNA. Due to its carcinogenic effects, commercial production of 4-aminobiphenyl ceased in the United States in the 1950s.

Third-hand smoke is contamination by tobacco smoke that lingers following the extinguishing of a cigarette, cigar, or other combustible tobacco product.

Ernst Ludwig Wynder, M.D. was an American epidemiology and public health researcher who studied the health effects of smoking tobacco. His and Evarts Ambrose Graham joint publication of "Tobacco Smoking as a Possible Etiologic Factor in Bronchiogenic Carcinoma: A Study of 684 Proved Cases" appeared in the Journal of the American Medical Association. It was one of the first major scientific publications identifying smoking as a contributory cause of lung cancer.


Mu‘assel is a syrupy tobacco mix containing molasses and vegetable glycerol which is smoked in a hookah. It is also known as "shisha" in the United States.

Smoking and pregnancy specific developmental disorder that is characterized by physical, behavioral and learning birth defects resulting from maternal ingestion of nicotine during pregnancy

Tobacco smoking and pregnancy is related to many effects on health and reproduction, in addition to the general health effects of tobacco. A number of studies have shown that tobacco use is a significant factor in miscarriages among pregnant smokers, and that it contributes to a number of other threats to the health of the fetus.

Animals are exposed to tobacco smoke and other cigarette by-products through their use as experimental subjects and through contact with smokers, as in the case of pets in houses where smoking takes place.

Safety of electronic cigarettes

The safetyofelectronic cigarettes is uncertain. There is little data about their safety, and considerable variation among e-cigarettes and in their liquid ingredients and thus the contents of the aerosol delivered to the user. Reviews on the safety of e-cigarettes have reached significantly different conclusions. A 2014 World Health Organization (WHO) report cautioned about potential risks of using e-cigarettes. Regulated US Food and Drug Administration (FDA) products such as nicotine inhalers may be safer than e-cigarettes, but e-cigarettes are generally considered safer than tobacco. It is estimated their safety risk is similar to that of smokeless tobacco, which has about 1% of the mortality risk of traditional cigarettes. A systematic review suggests that e-cigarettes are less harmful than smoking and since they contain no tobacco and do not involve combustion, users may avoid several harmful constituents usually found in tobacco smoke, such as ash, tar, and carbon monoxide. However, e-cigarettes cannot be considered harmless. Repeated exposure over a long time to e-cigarette vapor poses substantial potential risk.

Composition of electronic cigarette aerosol

The composition of the electronic cigaretteaerosol varies across and within manufacturers. Limited data exists regarding their chemistry. The aerosol of e-cigarettes is generated when the e-liquid reaches a temperature of roughly 100–250 °C within a chamber, which is thought to cause pyrolysis of the e-liquid and could also lead to decomposition of other liquid ingredients. The aerosol (mist) produced by an e-cigarette is commonly but inaccurately called vapor. The e-cigarette vapor simulates cigarette smoke, but without tobacco combustion. The e-cigarette vapor looks like cigarette smoke to some extent. E-cigarettes do not produce vapor between puffs. The e-cigarette vapor usually contains propylene glycol, glycerin, nicotine, flavors, aroma transporters, and other substances. The levels of nicotine, tobacco-specific nitrosamines (TSNAs), aldehydes, metals, volatile organic compounds (VOCs), flavors, and tobacco alkaloids in e-cigarette vapors vary greatly. The yield of chemicals found in the e-cigarette vapor varies depending on, several factors, including the e-liquid contents, puffing rate, and the battery voltage.

The Center for Indoor Air Research was a non-profit organization established by three American tobacco companies—Philip Morris, R.J. Reynolds, and Lorillard—in Linthicum, Maryland, in 1988. The organization funded research on indoor air pollution, some of which pertained to passive smoking and some of which did not. It also funded research pertaining to causes of lung cancer other than passive smoking, such as diet. The organization disbanded in 1998 as a result of the Tobacco Master Settlement Agreement.


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