Exposure to the toxins in secondhand smoke can cause asthma, cancer and other serious problems. Know what you're breathing — and consider practical steps for clearing the air.

By Mayo Clinic Staff

You don't smoke because you understand the dangers — but what about smoke you inhale involuntarily? Secondhand smoke causes or contributes to various health problems, including heart disease and lung cancer. Understand what's in secondhand smoke, and consider ways to protect yourself and those you love from it.

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 toxic chemicals, including:

  • Ammonia, used in cleaning products
  • Butane, used in lighter fluid
  • Carbon monoxide, found in car exhaust
  • Chromium, used to make steel
  • Cyanide, used in chemical weapons
  • Formaldehyde, an industrial chemical
  • Lead, a toxic metal
  • Polonium, a radioactive substance

The dangerous particles in secondhand smoke can linger in the air for hours or even longer. It isn't just the smoke that's a concern, though. The residue that clings to a smoker's hair and clothing, as well as cushions, carpeting and other goods — sometimes referred to as thirdhand smoke — also can pose risks, especially for children.

Secondhand smoke causes or contributes to serious health problems, including:

  • Cancer. Secondhand smoke is a known risk factor for lung cancer. In addition, secondhand smoke contains benzene — which increases the risk of leukemia.
  • Heart disease. Secondhand smoke damages blood vessels and interferes with circulation, which increases the risk of heart disease and heart attack. Recent research suggests that secondhand smoke also increases the risk of sudden cardiac death.
  • Lung disease. Exposure to secondhand smoke can aggravate respiratory conditions, such as chronic obstructive pulmonary disease (COPD).

Secondhand smoke poses additional risks for children, who are especially vulnerable to the effects of secondhand smoke. Problems include:

  • Low birth weight. Exposure to secondhand smoke during pregnancy increases the risk of low birth weight.
  • Sudden infant death syndrome (SIDS). Secondhand smoke increases the risk of SIDS.
  • Asthma and respiratory illness. Secondhand smoke increases the risk — and severity — of childhood asthma. Secondhand smoke also causes chronic coughing, phlegm and wheezing.
  • Infections. Children who live with people who smoke are more likely to develop bronchitis and pneumonia.

While further study is needed, limited research suggests that electronic cigarettes also expose bystanders to significant concentrations of aerosolized nicotine.

With planning, you can reduce or eliminate exposure to secondhand smoke. Start with these simple steps:

  • Don't allow smoking in your home. If family members or guests want to smoke, ask them to step outside. Air conditioners and ventilation systems don't effectively remove secondhand smoke from the air.
  • Don't allow smoking in your vehicle. If a passenger must smoke while you're traveling, stop as needed for smoke breaks outside the car.
  • Insist that smoking restrictions be enforced at work. Many states have laws against smoking in the workplace.
  • Choose smoke-free care facilities. This applies to child care facilities as well as facilities for older adults.
  • Patronize businesses with no-smoking policies. Choose smoke-free restaurants. When you travel, request nonsmoking hotel rooms.

If you have a partner or other loved one who smokes, offer support and encouragement to stop smoking. The entire family will reap the benefits.

Mar. 26, 2015