General Information About Secondhand Smoke

• Secondhand smoke (SHS) is smoke from burning tobacco products, like cigarettes, cigars, hookahs, or pipes.^1,2,3
• Secondhand smoke exposure occurs when people breathe in smoke breathed out by people who smoke or from burning tobacco products.
• There is no safe level of exposure to secondhand smoke; even brief exposure can cause serious health problems and be deadly.^1,4,5
• Completely eliminating smoking is the only way to fully protect people who do not smoke from secondhand smoke exposure.⁴

There is no safe level of exposure to secondhand smoke; even brief exposure can cause serious health problems.^1,4,5 Secondhand smoke can cause coronary heart disease, stroke, and lung cancer in adults who do not smoke.^1,4 Because their bodies are still growing, infants and young children are especially impacted by health problems caused by secondhand smoke. Children exposed to secondhand smoke are at an increased risk for sudden infant death syndrome (SIDS), acute respiratory infections such as pneumonia and bronchitis, middle ear disease, more frequent and severe asthma, respiratory symptoms, and slowed lung growth.^1,4

Most people are exposed to secondhand smoke in their homes or their places of work. People may also be exposed to secondhand smoke in public places like bars, restaurants, and casinos. ^1,4,5 People are more likely to be exposed to secondhand smoke if they live in multi-unit housing—like apartment buildings with many homes next to one another in the same place.^7,8 Even when no one in the home smokes, secondhand smoke can drift from other units including via hallways, stairwells, and ventilation systems.⁸

Eliminating smoking is the only way to fully protect people from secondhand smoke exposure. The harm caused by secondhand smoke is preventable. Comprehensive smokefree laws and policies that prohibit smoking in all areas of indoor spaces are the only way to fully protect people who do not smoke from secondhand smoke exposure.⁴ Comprehensive smokefree laws and policies can also help people quit smoking and can help keep young people from starting to smoke.^4,9,10 These laws and policies must be applied equitably to ensure all people have a fair and just opportunity to breathe smokefree air and be as healthy as possible.

Most comprehensive smokefree laws and policies also prohibit the use of e-cigarettes. The e-cigarette aerosol that people who use e-cigarettes breathe from the device and exhale can contain harmful and potentially harmful substances.¹¹ Including e-cigarettes in smokefree or tobacco-free policies can protect people who do not use e-cigarettes from exposure to e-cigarette emissions and can help change social norms about tobacco use. More information about e-cigarettes can be found on the Electronic Cigarettes page.