No amount of secondhand smoke is safe, according to the U.S. Surgeon General. Yet more than 126 million nonsmoking Americans are exposed to other people’s smoke at home and on the job.

What is secondhand smoke?

Secondhand smoke, also known as tobacco smoke pollution or environmental tobacco smoke, is a smoker’s exhaled smoke plus the smoke from that person’s lit cigarette, cigar, or pipe. Breathing this smoke is referred to as passive smoking or involuntary smoking. Inhaling another person’s smoke is like smoking. Many of the harmful substances in tobacco stay in the air and go into your lungs and bloodstream. Secondhand smoke is a poisonous cocktail that includes lead, carbon monoxide, arsenic, ammonia, formaldehyde, and a type of cyanide.

Cigars create larger amounts of secondhand smoke than cigarettes because they contain more tobacco and burn longer.

Cancer and secondhand smoke

Secondhand smoke is a known carcinogen (a substance that causes cancer). Many research studies show that inhaling secondhand smoke causes lung cancer in adults who do not smoke. Approximately 3,000 nonsmokers die of lung cancer each year.

The Surgeon General estimates that living with a smoker increases the chance of getting lung cancer by up to 30%. And a recent large study showed that the risk of lung cancer is nearly twice as high when the first exposure to secondhand smoke occurs before age 25, compared with later in life.

Research has not yet proved that secondhand smoke causes cancers other than lung cancer. But there is some evidence that exposure to secondhand smoke may raise an adult’s risk of the following cancers:

• Breast cancer
  
  
• Some types of head and neck cancer, such as nasopharyngeal cancer and nasal sinus cancer.

There is also a possible link in children between secondhand smoke and the following cancers:

• Brain tumors
  
  
• Leukemia
  
  
• Lymphoma

Many studies show that secondhand smoke causes a large number of other health problems for people of all ages, from heart disease in adults to higher rates of pneumonia in children. In fact, the American Heart Association estimates that more than 35,000 nonsmokers die every year as a result of exposure to secondhand smoke. Pregnant women, older adults, and people with respiratory conditions and heart disease are especially at risk for the health effects of secondhand smoke.

Secondhand smoke is also especially unsafe for babies and young kids because their bodies and lungs are still developing. In fact, some researchers suggest that the toxins from smoke that remain in a person’s hair and clothes or in carpet and furniture are hazardous to infants and children. Researchers describe this gradual buildup of toxins from secondhand smoke as “thirdhand smoke.” Read how to give your kids a smoke-free childhood.

How to avoid secondhand smoke

When someone smokes indoors, it is not enough to keep the smoke away by opening a window or using a fan. The only way to avoid the risks of secondhand smoke is to not be in an indoor space where smoking occurs.

Here are ways you can protect yourself and your family from secondhand smoke.

• Keep your home and car smoke free.
  
  
• If your workplace does not ban smoking, ask for restrictions, such as prohibiting smoking indoors.
  
  
• Eat in restaurants that are smoke free. Nonsmoking sections do not protect from secondhand smoke.
  
  
• When you travel, stay in smoke-free hotels and rent nonsmoking rental cars.
  
  
• When indoors, ask smokers to step outside.
  
  
• If you live with a smoker, ask the person to smoke outside.
  
  
• If you smoke, quit. Find resources to help you quit smoking and get answers to common questions and myths about quitting smoking.

Anti-smoking laws

Experts say that the only way to fully protect people from secondhand smoke is to get rid of smoking indoors. Anti-smoking laws have helped reduce the exposure to secondhand smoke of nonsmoking Americans from 88% in 1988 to 43% in 2002.

Most states have passed laws banning or limiting smoking in public places, including the workplace. Almost half of the states and Washington, D.C., also do not allow smoking in restaurants and bars. Many counties and cities also have passed smoke-free laws.

Find out more about your state’s smoking laws.

More Information

Tobacco

Additional Resources

Centers for Disease Control and Prevention: Secondhand Smoke

National Cancer Institute: Secondhand Smoke: Questions and Answers

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Last Updated: February 02, 2009