Health Risks of Secondhand Smoke

No amount of secondhand smoke is safe

Young child being exposed to secondhand smoke
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Secondhand smoke, also known as passive smoking, occurs as a result of breathing in pollutants in the air from tobacco products. According to the American Lung Association, smoke emitted from tobacco contains about 7,000 toxic chemicals, and of these, 70 are known to be linked to cancer (carcinogenic). 

This means that each time someone lights up a cigarette, poisonous chemicals such as benzene, formaldehyde, vinyl chloride, arsenic ammonia, hydrogen cyanide, and carbon monoxide is released into the air. As smokers inhale these poisonous substances directly, nonsmokers do so in an indirect manner, as a result of secondhand smoke.

What Is Secondhand Smoke?

Secondhand smoke is a combination of two types of smoke: mainstream smoke, which is actually exhaled from the person who is smoking, and sidestream smoke, which is emitted from the end of a burning cigarette. Both types contain the same toxic carcinogens.

Secondhand Smoke Deaths 

The American Lung Association estimates that secondhand smoke is responsible for over 40,000 deaths each year. There are no safe levels of secondhand smoke. Even a brief exposure can trigger a heart attack or an exacerbation of a wide range of negative health consequences. Additionally, exposure to secondhand smoke causes disease and premature death in children and adults who don't smoke.

Groups at Risk

Although everyone exposed to secondhand smoke is at risk, certain groups of people are at higher risk for developing severe problems from secondhand smoke. This includes unborn babies and newborns, children and teens, and people with asthma or other respiratory conditions, including those with COPD. The Surgeon General and the Environmental Protection Agency (EPA) recommend that no one smoke when young people are present.


Secondhand smoke is a major respiratory irritant. It can both cause and worsen respiratory conditions, including COPD. Adults with COPD are particularly at risk when exposed to secondhand smoke, often developing a worsening of symptoms, including increased shortness of breath, cough, and mucus production. Moreover, secondhand smoke acts as a major trigger for asthma. Just the odor of smoke on clothing or skin is enough to trigger symptoms.

Declared by the EPA as a human lung carcinogen, secondhand smoke is responsible for approximately 3,400 lung cancer deaths annually in American nonsmokers. It also causes between 22,700 to 69,600 deaths in the United States from heart disease each year, and although further studies are needed to confirm this link, it has been associated with stroke and hardening of the arteries.

Babies and Newborns

When a woman smokes during pregnancy, the unborn child receives less oxygen and develops an increased level of carbon monoxide in his or her bloodstream. This can lead to a higher incidence of miscarriage, premature birth, stillbirth, and sudden infant death syndrome (SIDS). Babies exposed to cigarette smoke in the womb are also at risk for low birth weight and other complications. Additionally, there is a definite connection between smoking during pregnancy and SIDS. In fact, infants of mothers who smoke are more than two times likely to die of SIDS than children of non-smokers.

Children and Teens

While there is good news that exposure to secondhand smoke is declining in the past decade, 37 percent of American children (24 million) are still exposed to secondhand smoke, according to the American Lung Association.

Because children have smaller airways, they are more sensitive to secondhand smoke than adults. When a child is exposed to secondhand smoke, his or her ability to breathe becomes impaired, as the airways become inflamed and filled with mucus. This leaves them more susceptible to respiratory symptoms such as coughing and wheezing and often leads to respiratory infection.

Secondhand smoke is associated with 7,500 to 15,000 hospitalizations of infants and toddlers annually and leads to 136 to 212 deaths in children 18 months of age or younger each year. Furthermore, because secondhand smoke irritates the airways of the lungs, it is a powerful trigger for children who have asthma, contributing to 8,000 to 26,000 new cases each year in children. It is also known to aggravate asthma symptoms in 400,000 to 1,000,000 children with asthma.

Children and teens of parents who smoke not only develop more frequent respiratory infections but have more difficulty recovering from them. Secondhand smoke is also known to be associated with middle ear infection, pneumonia, and bronchitis in children.

Teenage smoking is also a major health concern. It is not uncommon that teenagers of parents who smoke become smokers themselves. Teens are not only unaware of how addictive smoking is, but they can easily become addicted in a short period of time.

How to Prevent Exposure

It is extremely important if you have any type of respiratory condition, including asthma and COPD, that you not only quit smoking but avoid secondhand smoke as well. The following steps can be taken in an effort to prevent exposure:

  • Never allow anyone to smoke inside your home, office, or car.
  • Explain your “smoke-free home” policy to everyone who visits. People who really care about you will respect and support your house rules.
  • Discourage smoking behavior in your home by removing all ashtrays.
  • Advise guests and family members, if they must, to smoke outside, away from open windows or doors.
  • Do not frequent places where people are smoking. If you must be in an area where public smoking is taking place, sit or stand in a well-ventilated, non-smoking section of that area.
  • If family members smoke, suggest that they quit.
  • If you or a loved one is having difficulty quitting, talk to your health care team about getting help. Nicotine replacement therapy and other medications are available and can increase your chances of successfully quitting.
  • Join, or suggest your loved one join a stop smoking support group. 

Although smoke-free ordinances exist in many cities across the country, more needs to be done to protect the health of all people, especially children. Continuing education in our schools and in the workplace can help shed light on this sensitive subject. Every individual is entitled to breathe clean, fresh air, free from the harmful effects of secondhand smoke.

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