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 of Environmental Tobacco Smoke (ETS), also known as passive smoking [2] The chemical constituents of sidestream smoke are different from those of directly inhaled ("mainstream") smoke. Evidence has shown that sidestream smoke may be more harmful than mainstream smoke.[3] Sidestream smoking has been classified as a Class A carcinogen by the U.S. Environmental Protection Agency.
Contents |
Sidestream smoke is made up of many components. Some of the constituents of which are carbon monoxide, tar, nicotine, ammonia, benzene, cadmium and 4-aminobiphenyl.[4][5][6] 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, side stream has 2–6 times more condensate per gram than mainstream smoke.[4][5][6] 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.
There are over 250 toxins and carcinogens in cigarette smoke. The risks of getting lung cancer, brain tumors, acute myeloid leukemia, incidence of heart disease, and benign respiratory diseases increase by inhaling the sidestream smoke.[7] The chance of getting breast cancer and cervical cancer also increases with inhaling sidestream smoke. The relative risk of cardiovascular disease is 1.2–1.3 with exposure to sideastream smoke due the cyanide present in the smoke. There is also evidence that sidestream smoke causes negative effects both behaviorally and cognitively in children. One study on cotinine levels in children found that higher levels of cotinine in children were correlated with a decreased ability to perform in reading and math. [4][8]
Such factors as age, gender and different occupations put a person at risk for bladder cancer. Apart from these factors, smoking is the only other known risk cancer for bladder cancer. 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]
A non-smoker who is inhaling sidestream or secondhand 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 Surgeon General reported there was no safe level of smoke exposure at all.[12]
The 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.[13]
Following birth, a child’s exposure to contaminants in the air can have detrimental health effects including a heightened risk for respiratory tract infections, an increase in the likelihood of childhood asthma, as well as behavioral problems and reduction in neurocognitive abilities. Exposure to mainstream and sidestream smoke in children 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. This led experimenters to conclude that early childhood exposure to sidestream smoke. [14][15] [16]
A reduction in glutathione levels was observed following exposure to sidestream smoke in vitro. Glutathione is an antioxidant that resides in the lung after development. Following as little as a 20 minute exposure to sidestream smoke 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. Cancer could be the outcome for DNA mutations, while tumors could the outcome for the cell transformation and uncontrolled cell division which would be a result of direct exposure to sidestream smoke. [17][18]
During the 1980’s the Philip Morris Tobacco Company did research on sidestream smoke at Institut für Biologische Forschung that was never published. The study found sidestream smoke is nearly four times more toxic than mainstream smoke per gram. 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 animals weight gain to reach a point that is considered normal. The research team concluded that the only way to protect ourselves from sidestream smoke is to be in smoke free public places and workspaces.[3]