Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

Secondhand Smoke (SHS) Facts

Overview

Secondhand smoke is a mixture of gases and fine particles that includes:

  • Smoke from a burning tobacco product such as a cigarette, cigar, or pipe1,2
  • Smoke that has been exhaled or breathed out by the person or people smoking2
  • More than 7,000 chemicals, including hundreds that are toxic and about 70 that can cause cancer1

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, as well as multiunit housing and vehicles.3

Eliminating smoking in indoor spaces is the only way to fully protect nonsmokers from secondhand smoke exposure.3

Separating smokers from nonsmokers within the same air space, cleaning the air, opening windows, and ventilating buildings does not eliminate secondhand smoke exposure.3

Since 1964, 2.5 million nonsmokers have died from exposure to secondhand smoke.1

Health Effects: Children

In children, secondhand smoke causes the following:1,3

  • 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 U.S. children aged 18 months or younger, secondhand smoke exposure is responsible for:3

  • An estimated 150,000–300,000 new cases of bronchitis and pneumonia annually
  • Approximately 7,500–15,000 hospitalizations annually

Health Effects: Adults

In adults who have never smoked, secondhand smoke can cause cardiovascular disease and lung cancer.1,5

Cardiovascular Disease

  • 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.1,3
  • Nonsmokers who are exposed to secondhand smoke increase their heart disease risk by
    25–30%.3
  • It is estimated that secondhand smoke exposure caused nearly 34,000 heart disease deaths annually (during 2005–2009) among adult nonsmokers in the United States.1
  • Stroke is caused by exposure to secondhand smoke.1

Lung Cancer

  • Nonsmokers who are exposed to secondhand smoke at home or work increase their lung cancer risk by 20–30%.3
  • Secondhand smoke exposure causes an estimated more than 7,300 lung cancer deaths annually (for 2005–2009) among adult nonsmokers in the United States.1

There is no risk-free level of secondhand smoke exposure; even brief exposure can be harmful to health.1,3,4


Smoke-free laws can reduce the risk of heart disease and lung cancer among nonsmokers.1

Estimates of Secondhand Smoke Exposure

When a nonsmoker breathes in secondhand smoke, the body begins to metabolize or break down the nicotine that was in the smoke. During this process, a nicotine byproduct called cotinine is created. Exposure to nicotine and secondhand smoke can be measured by testing saliva, urine, or blood for the presence of cotinine.3


Secondhand Smoke Exposure Has Decreased in Recent Years

  • Measurements of cotinine have shown how exposure to secondhand smoke has steadily decreased in the United States over time.5*
    • During 1988–1991, approximately 87.9% of nonsmokers had measurable levels of cotinine.
    • During 1999–2000, approximately 52.5% of nonsmokers had measurable levels of cotinine.
    • During 2007–2008, approximately 40.1% of nonsmokers had measurable levels of cotinine.
  • The decrease in exposure to secondhand smoke is due to the growing number of laws that prohibit smoking in workplaces and public places, including restaurants and bars, the increase in the number of households with voluntary smoke-free home rules, and the decreases in adult and youth smoking rates.1,5,6,7,8
  • *This information will be updated in 2014.


Many in the United States Continue to be Exposed to Secondhand Smoke*

  • An estimated 88 million nonsmokers in the United States were exposed to secondhand smoke in 2007–2008.5
  • Children are at particular risk for exposure to secondhand smoke: 53.6% of young children (aged 3–11 years) were exposed to secondhand smoke in 2007–2008.5
  • While only 5.4% of adult nonsmokers in the United States lived with someone who smoked inside their home, 18.2% of children (aged 3–11 years) lived with someone who smoked inside their home in 2007–2008.5
  • Among children who live in homes in which no one smokes inside, those who live in multiunit housing have 45% higher cotinine levels compared to those who live in detached homes.9
  • Today about half of the children between ages 3 and 18 in the U.S. are exposed to cigarette smoke regularly, either at home or in places such as restaurants that still allow smoking.10
  • *This information will be updated in 2014.


Disparities in Secondhand Smoke Exposure

Racial and Ethnic Groups5

  • Although declines in cotinine levels have occurred in all racial and ethnic groups, cotinine levels have consistently been found to be higher in non-Hispanic black Americans than in non-Hispanic white Americans and Mexican Americans. In 2007–2008:
    • 55.9% of non-Hispanic blacks were exposed to secondhand smoke.
    • 40.1% of non-Hispanic whites were exposed to secondhand smoke.
    • 28.5% of Mexican Americans were exposed to secondhand smoke.

Low Income5

  • Secondhand smoke exposure tends to be high for persons with low incomes: 60.5% of persons living below the poverty level in the United States were exposed to secondhand smoke in
    2007–2008.

Occupational Disparities8

  • Occupational disparities in secondhand smoke exposure decreased over the past two decades, but substantial differences in exposure among workers remain.
  • African-American male workers, construction workers, and blue collar workers and service workers are some of the groups who continue to experience particularly high levels of secondhand smoke exposure relative to other workers.

Eliminating smoking in indoor spaces is the only way to fully protect nonsmokers from secondhand smoke exposure. Separating smokers from nonsmokers within the same air space, cleaning the air, opening windows, and ventilating buildings does not eliminate secondhand smoke exposure.3

References

  1. U.S. Department of Health and Human Services. The Health Consequences of Smoking—50 Years of Progress: A Report of the Surgeon General. Atlanta: U.S. 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 [accessed 2014 Apr 11].
  2. National Toxicology Program. Report on Carcinogens, Twelfth Edition. [PDF–7.22 MB] Research Triangle Park (NC): U.S. Department of Health and Human Sciences, National Institute of Environmental Health Sciences, National Toxicology Program, 2011 [accessed 2014 Apr 11].
  3. U.S. Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Atlanta: U.S. 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, 2006 [cited 2014 Apr 11].
  4. Institute of Medicine. Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence [PDF–707.47 KB]. Washington: National Academy of Sciences, Institute of Medicine, 2009 [accessed 2014 Apr 11].
  5. Centers for Disease Control and Prevention. Vital Signs: Nonsmokers' Exposure to Secondhand Smoke—United States, 1999–2008. Morbidity and Mortality Weekly Report 2010;59(35):1141–6 [accessed 2014 Apr 11].
  6. Pirkle JL, Bernert JT, Caudill SP, Sosnoff CS, Pechacek TF. Trends in the Exposure of Nonsmokers in the U.S. Population to Secondhand Smoke: 1988–2002. Environmental Health Perspectives 2006;114(6):853–8 [accessed 2014 Apr 11].
  7. Centers for Disease Control and Prevention. Fourth National Report on Human Exposure to Environmental Chemicals. [PDF–6.36 MB] Atlanta: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Environmental Health, 2009 [accessed 2014 Apr 11].
  8. Arheart KL, Lee DJ, Dietz NA, Wilkinson JD, Clark III JD, LeBlanc WG, Serdar B, Fleming LE. Declining Trends in Serum Cotinine Levels in U.S. Worker Groups: The Power of Policy. Journal of Occupational and Environmental Medicine 2008;50(1):57–63 [cited 2014 Apr 11].
  9. Wilson KM,, Klein JD, Blumkin AK, Gottlieb M, Winickoff JP.Tobacco Smoke Exposure in Children Who Live in Multiunit Housing. [PDF–575 KB] Pediatrics 2011:127(1):85-92 [accessed 2014 Apr 11].
  10. U.S. Department of Health and Human Services. Let’s Make the Next Generation
    Tobacco-Free: Your Guide to the 50th Anniversary Surgeon General’s Report on Smoking and Health
    .
    [PDF–795 KB] Atlanta: U.S. 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 [accessed 2014 Apr 11].
  • For Further Information

    Centers for Disease Control and Prevention
    National Center for Chronic Disease Prevention and Health Promotion
    Office on Smoking and Health
    E-mail: tobaccoinfo@cdc.gov
    Phone: 1-800-CDC-INFO

    Media Inquiries: Contact CDC's Office on Smoking and Health press line at 770-488-5493.

     

    File Formats: All viewers, players, and plug-ins used on this site can be downloaded from the file formats page. (For example: Adobe Acrobat Reader for pdf files, Windows Media Player for audio and video files, PowerPoint Viewer for presentation slides, etc.)

 
You Can Quit. Learn more.
CDC 24/7 – Saving Lives, Protecting People, Saving Money. Learn More About How CDC Works For You…
Contact Us:
  • CDC/Office on Smoking and Health
    4770 Buford Highway
    MS F-79
    Atlanta, Georgia 30341-3717
  • 800-CDC-INFO
    (800-232-4636)
    TTY: (888) 232-6348
    Contact CDC-INFO
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Rd. Atlanta, GA 30333, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC-INFO