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The Dangers of Secondhand Smoke

Last Updated November 2023 | This article was created by familydoctor.org editorial staff and reviewed by Beth Oller, MD

Secondhand smoke is the combination of smoke exhaled by a smoker and smoke that comes out of the burning end of a tobacco product. Each time someone is exposed to secondhand smoke from traditional tobacco cigarettes, pipes, or cigars, they are inhaling more than 7,000 chemicals. Most of those chemicals are harmful and can affect a person’s health and development. About 70 of those chemicals can cause cancer. Secondhand smoke from e-cigarettes, which comes in the form of aerosol, contains harmful chemicals as well, including nicotine.

Repeated smoking stays in your home’s air, in curtains, bedding, carpeting, and furniture. That means your child can continue to be exposed to the harmful effects of secondhand smoke for a while.

Secondhand smoke is toxic for people of all ages. It’s even more dangerous for babies, young children, and teens because their brains and bodies are still developing. Unfortunately, babies and young children are exposed to secondhand smoke more than adults because they cannot leave the house or car where someone is smoking.

Path to improved health

To prevent secondhand smoke, you should stop smoking. That is the only way to protect your health and limit your family’s exposure to secondhand smoke. Fortunately, many states, counties, and cities have nonsmoking laws in public places to protect people from secondhand smoke.

Federal laws prohibit smoking in federal buildings, in buildings that are owned, rented, or leased by the executive branch of the federal government, or in buildings that house programs receiving federal funding. For example, this would apply to the U.S. government’s Head Start early childhood education programs. Smoking bans vary by county, city, and state. However, most laws are set up to protect people from secondhand smoke.

Your home and car: If you must smoke, keep your home and car smoke free. The closer someone is to secondhand smoke, the more chemicals they inhale. Instead, smoke outdoors, far enough away from your home or car to prevent the smoke from blowing back inside. Smoke also stays on your clothes. You should wear a separate jacket when you smoke outside. Leaving the car window down while you smoke is of no use. Do not allow friends, family, or your childcare provider to smoke inside your home when they are visiting.

Your child’s school and childcare: Local and state laws usually share a common interest in protecting children from secondhand smoke. Laws ban smoking in schools, commercial daycare centers, hospitals, and public buildings. If you see someone ignoring the no-smoking rule, notify the person in charge of that facility.

For private or in-home daycare centers, check the laws in your state. If there is no law prohibiting smoking, ask your childcare provider not to smoke inside the home or car. If that is not an option, consider choosing a different childcare provider.

Public places: You can reduce the amount of secondhand smoke your child inhales by making smart choices when you’re in public. For example, choose smoke-free restaurants and hotels. Sitting in a nonsmoking section does not offer any protection. Many hotels offer smoking and smoke-free rooms. Ask for a nonsmoking hotel room on a nonsmoking floor.

Some public places, such as sporting facilities, do not allow smoking inside. However, be aware that many smokers light up near the exit. You may encounter smoke as you are coming or going.

Continue to educate your child about the dangers of tobacco smoke. Emphasize the importance of never smoking. As your child gets older, continue to meet and get to know their friends. Ask your child if any of their friends smoke and continue to promote a healthy lifestyle.

Things to consider

Secondhand smoke can lead to a number of immediate and long-term illnesses for your child. Children who grow up in homes with a smoker have a higher level of cotinine in their bloodstream than those who grew up in a nonsmoking home. Cotinine is formed when tobacco smoke enters a person’s body. The younger your child is when they are exposed to secondhand smoke, the more serious the effects. These can include:

  • Frequent and chronic ear infections. Repeated ear infections may require surgery for ear tubes.
  • Newly diagnosed or worsened asthma.
  • Low birth weight, which leads to poor lung function.
  • A chronic cough, phlegm, wheezing, breathlessness, or repeated respiratory infections, such as bronchitis and pneumonia.
  • Sudden infant death syndrome (SIDS). SIDS is the somewhat unexplained reason a baby under the age of 1 dies in its sleep.
  • Lung cancer and heart disease in adults who have never smoked.

AAFP has guidelines for doctors that provide smokers with guidance on how to stop smoking. AAFP also recommends that primary care doctors provide school-age children and young adults with education or counseling to prevent tobacco use.

Questions to ask your doctor

  • My spouse or close family member smokes. Can you recommend tools and advice to help them stop smoking?
  • Is secondhand smoke less serious than smoking?
  • Is smoke from vape as harmful as smoke from cigarettes and other tobacco products?
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