Facts About How Secondhand Smoke Hurts Us

The Effects of Secondhand Smoke on Kids and Adults

Man Smoking
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When a cigarette is smoked, about half of the smoke is inhaled / exhaled (mainstream smoke) by the smoker and the other half comes from the lit end of a smoldering cigarette(sidestream smoke). This combination of mainstream and sidestream smoke is what makes up secondhand smoke, also known as environmental tobacco smoke (ETS).

Secondhand smoke can cause immediate damage to people who breathe it in 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. Secondhand smoke is toxic air that we should all avoid.

Key Facts to Know about Secondhand Smoke

  • There is no safe level of exposure to secondhand smoke.

  • Secondhand smoke contains a host of toxic chemicals, including arsenic, carbon monoxide, hydrogen cyanide and ammonia.

  • Over the last 50 years, secondhand smoke has been the cause of death for 2.5 million non-smokers.

  • Secondhand smoke exposure increases the risk of heart disease by about 30 percent, causing approximately 34,000 deaths each year in the United States alone.

  • Children who are exposed to secondhand smoke tend to have more middle ear infections, asthma-related problems, bronchitis and pneumonia.

  • Pregnant women who breathe in cigarette smoke are at risk for miscarriage, stillbirth and ectopic pregnancy as well as having low birth-weight babies and losing their babies to SIDS.

    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.

    Secondhand smoke contains upwards of 70 chemicals that are known to cause cancer.

    We know secondhand smoke causes lung cancer, even in people who have never smoked.  

    Secondhand smoke may also be a factor in the development of breast cancer, nasal sinus cavity cancer, nasopharyngeal cancer, brain, bladder, stomach and rectal cancer in adults.  And in children, secondhand smoke exposure may increase the risk of leukemia, lymphoma, and brain tumors. Conclusive evidence that links these diseases to secondhand smoke has not yet been uncovered, but research continues.

    Surprising Facts about Secondhand Smoke and Cancer

    • 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.
      • Non-smokers 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.

      The Risks of Secondhand Smoke to Children

      According to the American Heart Association, exposure to secondhand smoke is particularly risky for children and could cause long term damage to a child's health.  

      In a September 2016 report, parents are urged to have a "zero tolerance" toward secondhand smoke, noting that it can cause lifelong cardiovascular and respiratory problems along with other health issues for their children.

      In addition, we know that secondhand smoke is linked to:

      • Low birth weight 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.

      Read more: Secondhand Smoke and Children

      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.

      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.


      American Cancer Society. Health Risks of Secondhand Smoke. Reviewed November 13, 2015.

      American Heart Association. Circulation. Cardiovascular Effects of Secondhand Smoke.. May 23, 2005.

      American Heart Association. Circulation. Protect Kids from Secondhand Smoke, Experts Urge. September 12, 2016.

      U.S. Dept. of Health and Human Services. Surgeon General Reports. The Health Consequences of Involuntary Exposure to Tobacco Smoke. 2006.

      U.S. dept of Health and Human Services. Surgeon General Reports. The Health Consequences of Smoking - 50 Years of Progress. 2014.

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