https://www.cancer.org/Cancer/CancerCauses/TobaccoCancer/secondhand-smokeSecondhand smoke is classified as a "known human carcinogen" (cancer-causing agent) by the US Environmental Protection Agency (EPA), the US National Toxicology Program, and the International Agency for Research on Cancer (IARC), a branch of the World Health Organization.
Tobacco smoke contains over 4,000 chemical compounds. More than 60 of these are known or suspected to cause cancer.
Secondhand smoke causes other kinds of diseases and deaths
Secondhand smoke can cause harm in many ways. In the United States alone, each year it is responsible for:
- An estimated 46,000 deaths from heart disease in non-smokers who live with smokers
- About 3,400 lung cancer deaths in non-smoking adults
- Other breathing problems in non-smokers, including coughing, mucus, chest discomfort, and reduced lung function
- 50,000 to 300,000 lung infections (such as pneumonia and bronchitis) in children younger than 18 months of age, which result in 7,500 to 15,000 hospitalizations annually
- Increases in the number and severity of asthma attacks in about 200,000 to 1 million children who have asthma
- More than 750,000 middle ear infections in children
- Pregnant women exposed to secondhand smoke are also at increased risk of having low birth- weight babies.
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www.mayoclinic.com
What's in secondhand smoke?
Secondhand smoke — also known as environmental tobacco smoke — includes the smoke that a smoker exhales (mainstream smoke) and the smoke that comes directly from the burning tobacco product (sidestream smoke). Secondhand smoke contains thousands of toxic chemicals, including:
- Benzene
- Carbon monoxide
- Chromium
- Cyanide
- Formaldehyde
- Lead
- Nickel
- Polonium
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https://www.cancer.gov/newscenter/entertainment/tipsheet/secondhand-smoke
When a person is exposed to secondhand smoke, they are actually exposed to two forms of smoke.
Sidestream smoke is emitted between puffs of a burning cigarette, pipe or cigar, and
mainstream smoke is exhaled by the smoker. SHS contains thousands of chemicals, including formaldehyde, cyanide, carbon monoxide, ammonia, and nicotine. At least 250 chemicals in SHS are known to be toxic and/or cancer-causing agents.
https://www.who.int/features/factfiles/tobacco/en/index.html
Facts on second-hand smoke. World healht Organization.
Guidelines to Article 8 of the WHO Framework Convention on Tobacco Control state that there is “no safe level of exposure to tobacco smoke”. Creating 100% smoke-free environments is the only way to protect people from the harmful effects of second-hand tobacco smoke.
Separate or ventilated smoking areas do not protect non-smokers from second-hand smoke. Second-hand smoke can spread from a smoking area to a non-smoking area, even if the doors between the two areas are closed and even if ventilation is provided. Only 100% smoke-free environments provide effective protection.
About 40% of all children are regularly exposed to second-hand smoke at home. Thirty-one per cent of the deaths attributable to second-hand smoke occur in children.
Youths exposed to second-hand smoke at home are one-and-a-half to two times more likely to start smoking than those not exposed.
More than 94% of people are unprotected by smoke-free laws. However, in 2008 the number of people protected from second-hand smoke by such laws increased by 74% to 362 million from 208 million in 2007. Of the 100 most populous cities, 22 are smoke-free.
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https://www.cancer.gov/cancertopics/factsheet/Tobacco/ETS
- Does secondhand smoke contain harmful chemicals? Yes. Of the more than 4,000 chemicals that have been identified in secondhand tobacco smoke, at least 250 are known to be harmful, and 50 of these are known to cause cancer. These chemicals include (1):
- arsenic (a heavy metal toxin)
- benzene (a chemical found in gasoline)
- beryllium (a toxic metal)
- cadmium (a metal used in batteries)
- chromium (a metallic element)
- ethylene oxide (a chemical used to sterilize medical devices)
- nickel (a metallic element)
- polonium–210 (a chemical element that gives off radiation)
- vinyl chloride (a toxic substance used in plastics manufacture)
Many factors affect which chemicals are found in secondhand smoke, including the type of tobacco, the chemicals added to the tobacco, the way the product is smoked, and the paper in which the tobacco is wrapped (1, 3, 4).
- Does exposure to secondhand smoke cause cancer? Yes. The U.S. Environmental Protection Agency (EPA), the U.S. National Toxicology Program (NTP), the U.S. Surgeon General, and the International Agency for Research on Cancer (IARC) have classified secondhand smoke as a known human carcinogen (cancer-causing agent) (1, 3, 5).
Inhaling secondhand smoke causes lung cancer in nonsmoking adults (4). Approximately 3,000 lung cancer deaths occur each year among adult nonsmokers in the United States as a result of exposure to secondhand smoke (2). The Surgeon General estimates that living with a smoker increases a nonsmokerʼs chances of developing lung cancer by 20 to 30 percent (4).
Some research suggests that secondhand smoke may increase the risk of breast cancer, nasal sinus cavity cancer, and nasopharyngeal cancer in adults, and leukemia, lymphoma, and brain tumors in children (4). Additional research is needed to learn whether a link exists between secondhand smoke exposure and these cancers.
- What are the other health effects of exposure to secondhand smoke? Secondhand smoke causes disease and premature death in nonsmoking adults and children (4). Exposure to secondhand smoke irritates the airways and has immediate harmful effects on a personʼs heart and blood vessels. It may increase the risk of heart disease by an estimated 25 to 30 percent (4). In the United States, secondhand smoke is thought to cause about 46,000 heart disease deaths each year (6). There may also be a link between exposure to secondhand smoke and the risk of stroke and hardening of the arteries; however, additional research is needed to confirm this link.
Children exposed to secondhand smoke are at an increased risk of sudden infant death syndrome (SIDS), ear infections, colds, pneumonia, bronchitis, and more severe asthma. Being exposed to secondhand smoke slows the growth of childrenʼs lungs and can cause them to cough, wheeze, and feel breathless (4).
- What is a safe level of secondhand smoke? There is no safe level of exposure to secondhand smoke. Studies have shown that even low levels of secondhand smoke exposure can be harmful. The only way to fully protect nonsmokers from secondhand smoke exposure is to completely eliminate smoking in indoor spaces. Separating smokers from nonsmokers, cleaning the air, and ventilating buildings cannot completely eliminate secondhand smoke exposure (4).
