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Secondhand Smoke

The dangers of smoking have been known for years. But experts warn that breathing in someone else's secondhand smoke is also a health risk.

What Is Secondhand Smoke?

Secondhand smoke is a mix of:

  • the smoke coming from the burning end of a cigarette or cigar, called sidestream smoke
  • the smoke that a smoker breathes out, called mainstream smoke

When non-smokers breathe in secondhand smoke, it can cause serious health problems. In fact, it is almost as dangerous as if they were smokers themselves.

What Are the Risks of Secondhand Smoke?

Smokers might not mean to put the people around them in danger, but they are. Secondhand smoke contains more than 7,000 chemicals, many of which can cause cancer or heart disease.

In kids, breathing in secondhand smoke can cause:

Kids who are around smoke also might:

  • miss more school days than kids who aren't around secondhand smoke
  • have trouble doing well in sports or being physically active

Secondhand smoke also is linked to SIDS (sudden infant death syndrome).

Later in life, kids exposed to secondhand smoke can be at risk for:

And kids who grow up in a home where parents smoke are more likely to become smokers too.

How Can Parents Protect Kids From Secondhand Smoke?

There are fewer smokers now than in years past. But chances are that someone in your family or someone you know still smokes. But it's never healthy for kids to breathe in tobacco smoke. Even occasional or brief exposures can take a toll on the body.

These two rules can help protect your kids (and yourself!) from secondhand smoke:

  1. No smoking inside the house: Smokers should go outside, away from other people, especially kids and pregnant women. Smoke lingers in the air hours after cigarettes are put out. So even if someone smokes in a room alone, other people will eventually inhale that smoke too.

    Smoke also sticks to people and their clothing, furniture, toys, and carpets. This "thirdhand smoke" can't be easily washed away with soap and water. Kids who touch surfaces with thirdhand smoke on them will absorb the dangerous chemicals through their skin and breathe them into their lungs. Smokers should wash their hands and change their clothes after a smoke before they hold or hug children.
  2. No smoking in a car with other people: Even blowing smoke out the window does little, if anything, to reduce smoke exposure.

Also, don't hesitate to speak up if someone smokes near your child. Politely ask the person not to, but be ready to move away from the smoker if things get uncomfortable.

If you smoke, try to quit. If you have other smokers in the family, offer support and encouragement to help them kick the habit. Quitting isn't easy because smoking is highly addictive. But there are many support groups and tobacco-free programs can help people stop. You also can find information and help online at:

Date reviewed: September 2019