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Facts about Secondhand Smoke

The Effects of Secondhand Smoke on Our Health

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Updated July 07, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Facts about Secondhand Smoke

Secondhand Smoke

Peter Dazeley/Photographer's Choice/Getty Images

Research has uncovered more than 7000 chemical compounds in secondhand smoke; 250 of which are known to be poisonous, and upwards of 70 that are carcinogenic.

When a cigarette is smoked, about half of the smoke is inhaled / exhaled (mainstream smoke) by the smoker and the other half floats around in the air (sidestream smoke). The combination of mainstream and sidestream smoke makes up secondhand smoke, also known as environmental tobacco smoke (ETS).

As stated in the 2006 report of the Surgeon General, The Health Consequences of Involuntary Exposure to Tobacco Smoke,

There is no safe level of exposure to secondhand smoke.

Secondhand smoke can cause immediate damage as well as contribute to the development of numerous diseases, including cancer and heart disease.

The following facts point out why it is so important to have smoking bans in place. No one should be forced to breathe in air tainted with cigarette smoke.

Secondhand Smoke and Cancer

The U.S. Environmental Protection Agency, the U.S. National Toxicology Program, the U.S. Surgeon General, and the International Agency for Research on Cancer have all classified secondhand smoke as a Group A carcinogen.

Scientists believe there may be a connection between the risk of numerous cancers and secondhand smoke, including breast cancer, nasal sinus cavity cancer, and nasopharyngeal cancer in adults and the risk of leukemia, lymphoma, and brain tumors in children. However, more research is needed. Conclusive evidence that links these diseases to secondhand smoke has not yet been uncovered.

Secondhand Smoke and Cancer Facts

  • Science has revealed 69 chemicals in secondhand smoke that are known to cause cancer, and research continues.
  • Non-smokers who are exposed to secondhand smoke at home or work increase their risk of lung cancer by 20 to 30 percent.
  • According to the Centers for Disease Control and Prevention, approximately 3400 non-smokers die every year from lung cancer caused by secondhand smoke.
  • Studies have shown that sidestream smoke contains two to five times the amount of some carcinogens in cigarette smoke as mainstream smoke.
  • Toxic chemicals in secondhand smoke damage cells, which can put them at risk for becoming cancerous now or in the future.
  • Research has shown that secondhand smoke depresses the function of some antioxidants that help repair cell damage, including that caused by smoking.
How Secondhand Smoke Can Affect the Heart
  • Secondhand smoke contributes to coronary heart disease.
  • Approximately 46,000 heart disease deaths in American non-smoking adults are attributable to secondhand smoke exposure.
  • Nonsmokers who breathe in secondhand smoke regularly increase their risk of heart disease by 25 to 30 percent.
  • Breathing in secondhand smoke causes immediate changes to the cardiovascular system in ways that increase the risk for a heart attack in people with existing heart disease.
Secondhand Smoke - Worse Than We Thought

The Risks of Secondhand Smoke to Children

  • Low birthweight for gestational age.
  • Sudden Infant Death Syndrome (SIDS)- children whose mothers smoked during pregnancy have an increased risk of SIDS.
  • The EPA estimates that secondhand smoke is responsible for between 150,000 and 300,000 respiratory infections like bronchitis and pneumonia in American children under the age of 18 months annually.
  • Asthma - According to the EPA, between 200,000 and 1,000,000 kids with asthma have their condition worsened by secondhand smoke every year. Also, passive smoking may also be responsible for thousands of new cases of childhood asthma every year.
  • School-aged children who breathe in secondhand smoke are at increased risk for coughs, wheezing and breathlessness.
  • Middle ear infections - exposure to secondhand smoke causes buildup of fluid in the middle ear, resulting in 700,000 to 1.6 million physician office visits yearly.
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Secondhand smoke is serious business, and should be a concern for anyone who breathes it in. Non-smokers inhaling secondhand smoke share some of the health risks smokers face. But smokers do face the worst of it; the risks of smoking are compounded by breathing cigarette smoke in for a second time.

Don't underestimate the dangers of secondhand smoke. While it may not kill as many people as smoking does, it is toxic and claims thousands of lives every year around the world.

Tell us what you think: Polls about Secondhand Smoke

Sources:

U.S. Dept. of Health and Human Services. Surgeon General Reports. The Health Consequences of Involuntary Exposure to Tobacco Smoke. http://www.surgeongeneral.gov/library/reports/secondhandsmoke/index.html. Accessed September 2012.

World Health Organization. About Secondhand Smoke. http://www.who.int/tobacco/research/secondhand_smoke/about/en/. Accessed September 2012.

Centers for Disease Control and Prevention. Smoking-Attributable Mortality, Years of Potential Life Lost, and Productivity Losses -- United States, 2000-2004. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5745a3.htm. Accessed July 2012.

United States Environmental Protection Agency. Tobacco Smoke. http://www.epa.gov/rpdweb00/sources/tobacco.html. Accessed July 2012.

National Cancer Institute. Secondhand Smoke and Cancer. http://www.cancer.gov/cancertopics/factsheet/Tobacco/ETS. Accessed July 2012.

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