What is passive tobacco smoke?

Second-hand tobacco smoke is the combination of the smoke from a burning tobacco product and the smoke exhaled by a smoker. It is also called environmental tobacco smoke, involuntary smoke and passive smoke.

More than 7,000 chemicals have been identified in secondhand tobacco smoke. At least 69 of these chemicals are known to cause cancer, including arsenic, benzene, beryllium, chromeand formaldehyde.

How are people exposed to secondhand smoke?

People can be exposed to secondhand smoke in homes, cars, workplaces and public places. In the United States, the source of most passive smoking is from cigarettes, followed by pipes, cigars, and other tobacco products.

What cancers are associated with passive smoking?

Inhalation of passive smoking causes lung cancer in non-smokers. Some studies also suggest that passive smoking can increase the risk of breast cancer, cancer of the sinus cavity of the noseand nasopharyngeal cancer in adults and leukemia, lymphomaand brain tumors in children, although more research is needed on this topic.

How can exposure to non-smokers be reduced?

There is no safe level of exposure to secondhand smoke; even low levels of secondhand smoke can be harmful. In the US, legislation has helped reduce non-smokers’ exposure to secondhand smoke. Federal law prohibits smoking on all domestic airlines, nearly all flights between the United States and foreign destinations, interstate buses, and most trains. Smoking is also prohibited in most federally owned buildings. Many state and local governments have also passed laws banning smoking in public facilities, such as schools, hospitals, and airports, as well as private workplaces, including restaurants and bars.

Internationally, an increasing number of nations require all workplaces, including bars and restaurants, to be smoke-free.

Selected references:

• National Toxicology Program. Tobacco-Related Exposures, Report on Carcinogens, Fifteenth Edition. Triangle Park, NC: National Institute of Environmental Health and Safety, 2021. Also available online. Last accessed December 8, 2022.
• Office for Smoking and Health. About passive smoke. Atlanta, GA: US Centers for Disease Control and Prevention, 2024. Available online. Last accessed 13 June 2024.
• US Department of Health and Human Services. The health consequences of involuntary exposure to tobacco smoke: a report from the surgeon general. Rockville, MD: US Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2006.
• US Department of Health and Human Services. The health consequences of smoking – 50 years of progress: a report from the Surgeon General. Atlanta: US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014.