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Background
Secondhand smoke (SHS) is a mixture of the sidestream smoke released by a smoldering cigarette, pipe, hookah/waterpipe, or cigar, and the mainstream smoke exhaled by a smoker. SHS is a complex mixture containing thousands of chemicals, including formaldehyde, cyanide, carbon monoxide, ammonia, and nicotine. More than 250 of the chemicals in SHS are known to be harmful, and at least 69 are known to cause cancer.
Conclusive scientific evidence documents that SHS causes premature death and disease in children and adults who do not smoke. Among adults, exposure to SHS has immediate adverse effects on the cardiovascular system, and long-term exposure to SHS causes coronary heart disease and lung cancer. Children exposed to SHS are at increased risk for sudden infant death syndrome, acute respiratory infections, middle ear disease, more severe asthma, respiratory symptoms, and slowed lung growth.
There is no risk-free level of exposure to SHS, and only eliminating smoking in indoor spaces fully protects nonsmokers from exposure to SHS. Exposure to SHS among nonsmokers can be assessed by measurement of cotinine, a metabolite of nicotine. While cotinine levels may vary by individual due to the speed of nicotine metabolism and cotinine clearance, detection of cotinine above a minimum threshold is a validated measure of exposure to SHS in nonsmokers.
Measure
The percentage of nonsmokers exposed to secondhand smoke. (The percentage of nonsmokers aged 3 years and older with a serum cotinine level greater than 0.05 ng/mL and less than or equal to 10 ng/mL.)
Healthy People 2030 Target
- Reduce the proportion of people who do not smoke but are exposed to secondhand smoke to 17.3%.
Healthy People 2030 is a set of goals set forth by the Department of Health and Human Services.
Note: Goals are indicated as blue line on Detailed Trend Graphs.
Data Source
Centers for Disease Control and Prevention, National Center for Health Statistics, National Health and Nutrition Examination Survey. “Secondhand smoke exposure” measure.
Trends and Most Recent Estimates
By Sex
Overview Graph | Detailed Trend Graphs | Most Recent Estimates (2017 to 2018) | |
---|---|---|---|
Percent of nonsmokers | 95% Confidence Interval | ||
![]() ![]() |
Both Sexes![]() |
25.8 | 22.8 - 28.7 |
Male![]() |
27.1 | 22.6 - 31.6 | |
Female![]() |
24.6 | 22.1 - 27.1 | |
¹The 1988-1994 estimate starts at age 4 instead of age 3. | |||
²As measured by a serum cotinine level of greater than 0.05 ng/ml and less than or equal to 10 ng/ml. |
By Race/Ethnicity
Overview Graph | Detailed Trend Graphs | Most Recent Estimates (2017 to 2018) | |
---|---|---|---|
Percent of nonsmokers | 95% Confidence Interval | ||
![]() ![]() |
All Races![]() |
25.8 | 22.8 - 28.7 |
Non-Hispanic White![]() |
24.5 | 20.9 - 28.2 | |
Non-Hispanic Black![]() |
47.8 | 41.5 - 54.0 | |
Hispanic![]() |
18.7 | 15.4 - 21.9 | |
¹The 1988-1994 estimate starts at age 4 instead of age 3. | |||
²As measured by a serum cotinine level of greater than 0.05 ng/ml and less than or equal to 10 ng/ml. |
By Age
Overview Graph | Detailed Trend Graphs | Most Recent Estimates (2017 to 2018) | |
---|---|---|---|
Percent of nonsmokers | 95% Confidence Interval | ||
![]() ![]() |
Ages 3-11![]() |
38.2 | 34.4 - 42.0 |
Ages 12-17![]() |
32.9 | 26.9 - 38.9 | |
Ages 18-29![]() |
33.9 | 28.1 - 39.8 | |
Ages 30+![]() |
19.6 | 16.5 - 22.8 | |
¹The 1988-1994 estimate starts at age 4 instead of age 3. | |||
²As measured by a serum cotinine level of greater than 0.05 ng/ml and less than or equal to 10 ng/ml. |
By Poverty Income Level
Overview Graph | Detailed Trend Graphs | Most Recent Estimates (2017 to 2018) | |
---|---|---|---|
Percent of nonsmokers | 95% Confidence Interval | ||
![]() ![]() |
<200% of federal poverty level![]() |
37.5 | 33.4 - 41.6 |
>=200% of federal poverty level![]() |
19.0 | 15.7 - 22.3 | |
¹As measured by a serum cotinine level of greater than 0.05 ng/ml and less than or equal to 10 ng/ml. |
By Education Level
Overview Graph | Detailed Trend Graphs | Most Recent Estimates (2017 to 2018) | |
---|---|---|---|
Percent of nonsmokers | 95% Confidence Interval | ||
![]() ![]() |
Less than High School![]() |
25.3 | 20.4 - 30.1 |
High School![]() |
27.5 | 22.4 - 32.5 | |
Greater than High School![]() |
17.9 | 14.6 - 21.2 | |
¹As measured by a serum cotinine level of greater than 0.05 ng/ml and less than or equal to 10 ng/ml. |
Additional Information on Secondhand Smoke Exposure
- Secondhand Smoke Exposure. National Cancer Institute.
- Secondhand Smoke and Cancer. National Cancer Institute.
- The Dangers of Secondhand Smoke. American Academy of Pediatrics.
- Health Risks of Secondhand Smoke. American Cancer Society.
- Smoking and Tobacco Use: Secondhand Smoke. Centers for Disease Control and Prevention.
- Smoke-Free Public Housing and Multifamily Properties. Department of Housing and Urban Development.
- Secondhand Smoke and Smoke-free Homes. Environmental Protection Agency.
- Report on Carcinogens. National Toxicology Program, U.S. Department of Health and Human Services.
- Secondhand Smoke and What it Means to You. U.S. Department of Health and Human Services.
- Tobacco Control Evidence-Based Programs Listing. National Cancer Institute.
- Surgeon General’s Reports on Smoking and Tobacco Use. Centers for Disease Control and Prevention.
- 50 Years of Progress: A Report of the Surgeon General, 2014. U.S. Department of Health and Human Services.
- The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General, 2006. U.S. Department of Health and Human Services.
- American Nonsmokers’ Rights Foundation.
- Overview List – How many smokefree laws? American Nonsmokers’ Rights Foundation.
- Summary of 100% Smokefree State Laws and Protected by 100% U.S. Smokefree Laws. American Nonsmokers’ Rights Foundation.
- U.S. 100% Smokefree Laws in Non-Hospitality Workplaces, Restaurants, and Bars. American Nonsmokers’ Rights Foundation.
- Tobacco Control Monograph Series. National Cancer Institute.
- Monograph 10: Health Effects of Exposure to Environmental Tobacco Smoke. National Cancer Institute.
- Smoke-free and tobacco-free colleges and universities in the United States. Blake KD, Klein AL, Walpert L, Casey L, Hallett C, Douglas C, Sinha B, Koh HK. Tob Control 2020;29(3):289-294.
- Secondhand Smoke Exposure Among Nonsmoking Adults: United States, 2015–2018. Brody DJ, Faust E, Tsai J. NCHS Data Brief 2021;396.
- State and local comprehensive smoke-free laws for worksites, restaurants, and bars—United States, 2015. Centers for Disease Control and Prevention. MMWR 2016;65(24)623-626.
- Uneven access to smoke-free laws and policies and its effect on health equity in the United States: 2000-2019. Hafez AY, Gonzalez M, Kulik MC, Vijayaraghavan M, Glantz SA. Am J Public Health 2019;109(11):1568-1575.
- Parental home smoking policies: the protective effect of having a young child in the household. Hawkins SS and Berkman L. Prev Med 2011;53(1–2):61–3.
- National and state estimates of secondhand smoke infiltration among U.S. multiunit housing residents. King BA, Babb SD, Tynan MA, Gerzoff RB. Nicotine Tob Res 2013 Jul;15(7):1316-21.
- Effects of Electronic Cigarettes on Indoor Air Quality and Health. Li L, Lin Y, Xia T, Zhu Y. Annu Rev Public Health 2020;41(2):363-380.
- Small Area Estimation of Smoke-free Workplace Polices and Home Rules in U.S. Counties. Liu B, Dompreh I, Hartman AM. Nicotine Tob Res. 2021; [Epub ahead of print]
- Exposure to Secondhand Smoke Among Nonsmokers in New York City in the Context of Recent Tobacco Control Policies: Current Status, Changes Over the Past Decade, and National Comparisons. Perlman SE, Chernov C, Farley SM, et al. Nicotine Tob Res 2016; 18(11):2065-2074.
- SIDS and Other Sleep-Related Infant Deaths: Updated 2016 Recommendations for a Safe Infant Sleeping Environment. Task Force on Sudden Infant Death Syndrome. Pediatrics 2016;138(5):e20162938.
- Exposure to Secondhand Smoke in Homes and Vehicles Among US Youths, United States, 2011-2019. Walton K, Gentzke AS, Murphy-Hoefer R, Kenemer B, Neff LJ. Preventing Chronic Disease 2020;17.
- Tobacco Use Supplement to the Current Population Survey. National Cancer Institute.
- Cancer Facts and Figures. American Cancer Society.
- Secondhand Smoke Exposure Among Nonsmoking Youth: United States, 2013-2016. Centers for Disease Control and Prevention.
- State Tobacco Activities Tracking and Evaluation System. Centers for Disease Control and Prevention.