Health Risks of Secondhand Smoke

Approved by the Lineagotica Editorial Board, 01/2019

Even if you do not smoke, you may be exposed to secondhand smoke. This type of smoke can come from:

  • Someone breathing out smoke while smoking

  • A burning cigarette, cigar, or pipe

You may also hear secondhand smoke called passive or involuntary smoke, tobacco smoke pollution, or environmental tobacco smoke.

There is no safe level of exposure to secondhand smoke. Even brief moments around secondhand smoke can harm a person’s health. And the risk of health problems is greater with more exposure.

Secondhand smoke and disease

Tobacco smoke has many harmful substances including:

  • Benzopyrene

  • Lead

  • Carbon monoxide

  • Arsenic

  • Ammonia

  • Formaldehyde

  • A type of cyanide

Many of these travel through the air into the lungs and bloodstream. This increases a person's risk of disease.

The U.S Surgeon General estimates that living with a person who smokes increases the chance of lung cancer by 20% to 30%. Research also suggests that secondhand smoke exposure may increase the risk of other cancers by at least 30%. These include cervical cancer, kidney cancer, nasopharyngeal cancer, rectal cancer, and brain tumors.

Secondhand smoke also causes other health problems, including asthma and heart disease. The following people have a higher risk of harmful health effects from secondhand smoke:

  • Pregnant women

  • Children

  • Older adults

  • People with breathing conditions or heart disease

Exposure to secondhand smoke causes lung inflammation and lowers levels of important vitamins right away. These effects can increase a person's likelihood of developing health problems.

Health risks for children

Secondhand smoke is especially unsafe for babies and young children because their bodies and lungs are still developing.

Children exposed to secondhand smoke have a higher risk of the following conditions:

  • Ear infections

  • Asthma attacks

  • Lung infections, such as bronchitis and pneumonia

  • Coughing and wheezing

  • Sudden infant death syndrome (SIDS)

Research also shows other links between secondhand smoke and child well-being. Examples include:

  • Increased risk of mental health issues and learning problems

  • Increased risk of starting to smoke

How to avoid secondhand smoke

People may think opening a window or using a fan prevents secondhand smoke exposure. But studies show that toxins from smoke do not go away. They remain in hair, clothes, carpets, and furniture. These toxins are often called “thirdhand smoke.”

The only way to prevent exposure is to avoid places where smoking occurs, particularly inside.

Here are some tips to protect you and your family from secondhand smoke:

  • If you smoke, quit. There are many resources to help you. Talk with your health care team about the best options for you.

  • Do not smoke or allow people to smoke in your house or car. Ask people who smoke to step outside.

  • Find smoke-free restaurants, hotels, and rental cars.

  • Ask caregivers and relatives to stop smoking around you and your children.

Smoke-free laws

Smoke-free workplace laws have helped lessen exposure to secondhand smoke and the related health problems. Most states have passed laws banning or limiting smoking in public places, including the workplace. Almost half of states and Washington, D.C., do not allow smoking in restaurants and bars. Many counties and cities also have smoke-free laws. Learn more about your local smoking laws on a separate website.

Related Resources

Benefits of Quitting Tobacco Use

Health Risks of E-cigarettes, Smokeless Tobacco, and Waterpipes

Resources to Help You Quit Smoking

More Information

Campaign for Tobacco-Free Kids: Smoke-Free Laws

Centers for Disease Control and Prevention: Secondhand Smoke Facts

National Cancer Institute: Secondhand Smoke and Cancer