Trends and Disparities in Secondhand Smoke

  • All people deserve a fair and just opportunity to breathe smokefree air and be as healthy as possible. However, because not all populations are equally protected by a comprehensive smokefree law intended to address exposure to secondhand smoke (SHS), it is not always possible for people to reach their full health potential.
  • The proportion of people who do not smoke and are exposed to secondhand smoke has declined in the US, but disparities in secondhand smoke exposure remain.1,2,3
  • Disparities in secondhand smoke exposure exist and persist because of uneven protections and unfair and unjust practices.1,2,3
  • More than a third of the US population lives in a state or community without protection from a comprehensive smokefree law that prohibits smoking in all workplaces and public places. In addition, many people who live in multi-unit housing (like apartment buildings) live in buildings without smokefree policies and are exposed to secondhand smoke because smoke travels between units of the same building.1,2,3

What are the trends in secondhand smoke exposure in the US?

The percentage of persons in the US who do not smoke and are exposed to secondhand smoke has decreased over the last 60 years.1,2,3 For example, between 1999-2000 and 2011-2012, secondhand smoke exposure in the US among persons who do not smoke was reduced by half.4 Likely reasons for the decline in secondhand smoke exposure are:4

  • Implementation of comprehensive smokefree laws that prohibit smoking in workplaces, restaurants, and bars
  • Decreased cigarette smoking prevalence
  • Increased awareness of the risks of secondhand smoke exposure
  • Adoption of voluntary smokefree home rules

What drives disparities in secondhand smoke exposure?

Uneven adoption of smokefree policies, unfair and unjust marketing and advertising practices by the tobacco industry, and social determinants of health (the conditions in which people are born, grow, live, work, and age) contribute to disparities in secondhand smoke exposure.

  • Smokefree policies are important because they protect people who do not smoke from secondhand smoke exposure, motivate those who use commercial tobacco to quit, and prevent people from starting to use commercial tobacco. Right now, not everyone in the nation is equally protected by these policies.
  • As of June 2021, of the ten US states with the highest proportion of Black residents, only three of those states have comprehensive smokefree laws that prohibit smoking in all workplaces and public places. Of the seven states that do not have comprehensive laws, two also prevent local communities from adopting comprehensive smokefree laws.5,6,7
  • As of July 2022, almost 38% of the US population is not protected by comprehensive smokefree laws at the state or community level.8
  • People of lower incomes and with less education may be less likely to be covered by comprehensive smokefree laws.3,9
  • Homes and vehicles remain major sources of secondhand smoke exposure for babies, children, and teens.2,9
  • People who live in multi-unit housing are more likely to be exposed to secondhand smoke because many buildings do not have smokefree building policies.
    • Approximately 1 in 3 multi-unit housing residents are covered by smokefree building policies.10
    • Many multi-unit housing buildings are rental properties. Secondhand smoke exposure during 2017-2018 was higher among people who rented (36.6%) their housing than those who owned their housing (19.2%).1
  • Comprehensive smokefree laws and policies that also prohibit the use of e-cigarettes can protect people who do not use e-cigarettes from exposure to e-cigarette emissions. The e-cigarette aerosol that people who use e-cigarettes breathe from the device and exhale can contain harmful and potentially harmful substances. More information about e-cigarettes can be found on the Electronic Cigarettes page.
  • A federal court found that tobacco companies deceived the American public about the health effects of secondhand smoke.11

Who is exposed to secondhand smoke?

Despite the decline in secondhand smoke exposure, not all populations are equitably protected by smokefree policies and some population groups remain more likely to be exposed.1,3,12 These groups include children ages 3-11 years; non-Hispanic, Black people; people with lower incomes; people with less education; people who live in rental and multi-unit housing; people who live with someone who smokes inside the home; and people who work in traditionally “blue collar” occupations.1,3,5,13

  • Almost two of every five children ages 3 to 11 years, including over half of non-Hispanic, Black children, were exposed to secondhand smoke during 2017- 2018.1,3
  • An estimated 6.7 million (25.3%) of middle and high school students self-reported secondhand smoke exposure in the home in 2019.14
  • Non-Hispanic Black people (47.2%) had a higher prevalence of secondhand smoke exposure than non-Hispanic Asian people (21.2%), Mexican American people (16.4%), and non-Hispanic White people (22.1%).1
  • People living below the poverty level (45.0%) have a higher prevalence of secondhand smoke exposure than those with incomes at or above the poverty level (21.4%).1
  • People aged 25 or older with a high-school education (24.3%) or those with less than high-school education (26.4%) have a higher prevalence of secondhand smoke exposure than people with a college diploma or higher (11.1%).1
  • An estimated 80 million people—or 25% of the population—in the US live in multi-unit housing—like apartment buildings with many homes next to one another in the same place such as apartments or condos.15
  • People who live in rental housing (36.6%) have a higher prevalence of secondhand smoke exposure than people who own their housing (18.6%).1
  • Even when no one in the home smokes, secondhand smoke can drift from other units including via hallways, stairwells, and ventilation systems.16
  • In homes where no one smokes, people who live in multi-unit housing such as apartments or condominiums have higher serum cotinine levels than people who live in single-family homes.16,17
  • People who live with someone who smokes inside the home (87.8%) have a higher prevalence of secondhand smoke exposure than people who do not live with someone who smokes in the home (21.4%).9
  • Secondhand smoke exposures in the workplace are more likely among workers who reside in states without comprehensive smokefree laws, and among workers employed in traditionally “blue collar” industries (e.g., construction, industrial machinery, or equipment repair).6

Secondhand smoke exposure can be measured either through conducting surveys or through lab tests. For example, most studies of blood tests look at how many people have serum cotinine levels  between 0.05-10 ng/mL. Serum cotinine levels in this range reflect recent exposure to nicotine in tobacco smoke at levels consistent with secondhand smoke exposure. People who smoke almost always have serum cotinine levels higher than 10 ng/mL.

  1. Tsai J, Homa DM, Neff LJ, PhD, Sosnoff CS, et al. Trends in Secondhand Smoke Exposure, 2011-2018: Impact and Implications of Expanding Serum Cotinine Range. Am J Prev Med 2021;000(000):1−9.
  2. US Department of Health and Human Services. The Health Consequences of Smoking—50 Years of Progress: A Report of the Surgeon General. Atlanta, GA: 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.
  3. Tsai J, Homa DM, Gentzke AS, Mahoney M, Sharapova S, Sosnoff S, et al. Exposure to Secondhand Smoke Among Nonsmokers—United States, 1988-2014. MMWR 2018;67(48): 1342-46.
  4. Homa DM, Neff LJ, King BA,  Caraballo RS, Bunnell RE, Babb SD, et al. Vital signs: disparities in nonsmokers’ exposure to secondhand smoke – United States, 1999-2012. MMWR 2015;64(4):103–108.
  5. Centers for Disease Control and Prevention. STATE System Preemption Fact Sheet [accessed 2022 Jul 15].
  6. US Census Bureau. Race and Ethnicity in the United States: 2010 Census and 2020 Census. Washington, DC: US Department of Commerce. [accessed 2022 Jul 15].
  7. Centers for Disease Control and Prevention. STATE System Smokefree Indoor Air Fact Sheet [accessed 2022 Jul 15].
  8. American Nonsmokers’ Rights Foundation. Overview List – Number of Smokefree and Other Tobacco Related Laws, July 2022 [accessed 2022 Jul 15].
  9. Huang J, King BA, Babb SD, Xu X, Hallett C, Hopkins M. Sociodemographic Disparities in Local Smoke-Free Law Coverage in 10 States. Am J Public Health 2015;105(9):1806-1813.
  10. Licht AS, King BA, Travers MJ, Rivard C, Hyland AJ. Attitudes, Experiences, and Acceptance of Smoke-Free Policies Among US Multiunit Housing Residents. American Journal of Public Health 2012;102(10):1868-1871.
  11. United States v. Philip Morris USA, Inc., et al., 449 F. Supp. 2d 1, United States District Court for the District of Columbia (2006).
  12. Shastri SS, Talluri R, Shete S. Disparities in Secondhand Smoke Exposure in the United States: National Health and Nutrition Examination Survey 2011-2018. JAMA Internal Medicine 2021;181(1):134-137.
  13. Su C, Syamlal G, Tamers S, Li J, Luckhaupt SE. Workplace Secondhand Tobacco Smoke Exposure Among Nonsmoking Workers, 2015. MMWR 2019;68(27):604-607.
  14. Walton K, Gentzke AS, Murphy-Hoefer R, Kenemer B, Neff LJ. Exposure to Secondhand Smoke in Homes and Vehicles Among US Youths, United States, 2011-2019. Preventing Chronic Disease 2020;17.
  15. King BA, Babb SD, Tynan MA, Gerzoff RB. National and state estimates of secondhand smoke infiltration among U.S. multiunit housing residents. Nicotine and Tobacco Research 2013a;15(7):1316–21.
  16. Wilson KM, Klein JD, Blumkin AK, Gottlieb M, Winickoff JP. Tobacco Smoke Exposure in Children Who Live in Multiunit Housing. Pediatrics 2011;127(1):85-92.
  17. Farley SM, Jasek J, Debchoudhury I, Van Becka K, Talatia A, Perlman SF, et al. Housing type and secondhand smoke exposure among non-smoking New York City adults, 2004 and 2013-2014. Preventive Medicine Reports 2022;27:101805.