Secondhand smoke is a mixture of gases and fine particles that includes:
- Smoke from a burning cigarette, cigar, or pipe tip
- Smoke that has been exhaled or breathed out by the person or people smoking
- More than 7,000 chemicals, including hundreds that are toxic and about 70 that can cause cancer
Most exposure to secondhand smoke occurs in homes and workplaces. Secondhand smoke exposure also continues to occur in public places such as restaurants, bars, and casinos and in private vehicles. Eliminating smoking in indoor spaces is the only way to fully protect nonsmokers from secondhand smoke exposure. Separating smokers from nonsmokers, cleaning the air, opening windows, and ventilating buildings does not eliminate secondhand smoke exposure.
Health Effects: Children
In children, secondhand smoke causes the following:
- Ear infections
- More frequent and severe asthma attacks
- Respiratory symptoms (e.g., coughing, sneezing, shortness of breath)
- Respiratory infections (i.e., bronchitis, pneumonia)
- A greater risk for sudden infant death syndrome (SIDS)
In children aged 18 months or younger, secondhand smoke exposure is responsible for:
- An estimated 150,000–300,000 new cases of bronchitis and pneumonia annually
- Approximately 7,500–15,000 hospitalizations annually in the United States
Health Effects: Adults
In adults who have never smoked, secondhand smoke can cause heart disease and/or lung cancer.
- For nonsmokers, breathing secondhand smoke has immediate harmful effects on the cardiovascular system that can increase the risk for heart attack. People who already have heart disease are at especially high risk.
- Nonsmokers who are exposed to secondhand smoke at home or work increase their heart disease risk by 25–30%.
- Secondhand smoke exposure causes an estimated 46,000 heart disease deaths annually among adult nonsmokers in the United States.
- Nonsmokers who are exposed to secondhand smoke at home or work increase their lung cancer risk by 20–30%.
- Secondhand smoke exposure causes an estimated 3,400 lung cancer deaths annually among adult nonsmokers in the United States.
(Updated June 2014)