What is thirdhand smoke?

The short answer:

Thirdhand smoke is the chemical residue from tobacco smoke. It is also called “tobacco smoke residue” or “stale tobacco smoke.” The chemicals in thirdhand smoke are toxic to humans, especially children. It can linger for years in dust and on household surfaces. It can also become embedded in carpets, furniture, clothes, and building materials. It is difficult and expensive to remove.

The long answer:

Thirdhand smoke is the chemical residue that persists after secondhand tobacco smoke has disappeared from the air. Secondhand smoke is a combination of the sidestream smoke of a cigarette and the mainstream smoke exhaled by smokers. Thirdhand smoke is not strictly smoke, but a mixture of toxic chemicals that stick to surfaces, become embedded in materials, such as carpets, walls, furniture, blankets, and toys, and can later be re-emitted back into the air and accumulate in house dust. Thirdhand smoke can linger indoors for years. People can be exposed to thirdhand smoke by touching contaminated surfaces (absorption through the skin), by eating contaminated objects or dust, and by breathing contaminated air and re-suspended thirdhand smoke components.

The U.S. Surgeon General has concluded that there is no safe level of exposure to tobacco smoke. The California Air Resource Board has classified secondhand smoke as a toxic air contaminant. Because secondhand smoke leads to thirdhand smoke, it is not surprising that numerous secondhand smoke constituents are also found in thirdhand smoke, such as human carcinogens, reproductive toxicants, and developmental toxicants (as defined by California’s Proposition 65 and the International Agency for Cancer Research). Some chemicals in thirdhand smoke are not found in freshly emitted tobacco smoke because they are the result of the chemical transformation of tobacco smoke components in the environment.

Do you have more questions about the toxic legacy of tobacco smoke, how it affects human health, and what we can do about it? Learn more here.

Updated: July 2022


Matt, G. E., P. J. Quintana, H. Destaillats, L. A. Gundel, M. Sleiman, B. C. Singer, P. Jacob, N. Benowitz, J. P. Winickoff, V. Rehan, P. Talbot, S. Schick, J. Samet, Y. Wang, B. Hang, M. Martins-Green, J. F. Pankow, and M. F. Hovell. 2011. “Thirdhand tobacco smoke: emerging evidence and arguments for a multidisciplinary research agenda.”  Environ Health Perspect 119 (9):1218-26. doi: 10.1289/ehp.1103500.

Jacob, P., 3rd, N. L. Benowitz, H. Destaillats, L. Gundel, B. Hang, M. Martins-Green, G. E. Matt, P. J. Quintana, J. M. Samet, S. F. Schick, P. Talbot, N. J. Aquilina, M. F. Hovell, J. H. Mao, and T. P. Whitehead. 2017. “Thirdhand Smoke: New Evidence, Challenges, and Future Directions.”  Chem Res Toxicol 30 (1):270-294. doi: 10.1021/acs.chemrestox.6b00343.

Sleiman M, Destaillats H, Smith JD, Liu C, Ahmed M, Wilson KR Gundel LA. Secondary organic aerosol formation from ozone-initiated reactions with nicotine and secondhand
tobacco smoke. Atmos Env. 2010; 44:4191-4198.

California Environmental Protection Agency, Air Resources Board, Office of Environmental Health Hazard Assessment. Technical support document for the “Proposed Identification of Environmental Tobacco Smoke as a Toxic Air Contaminant, Part A. http://www.arb.ca.gov/regact/ets2006/ets2006.htm

U.S. Department of Health and Human Services. 2006. The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Available: http://www.surgeongeneral.gov/library/secondhandsmoke/

State of California, Environmental Protection Agency. Chemicals Known to the State to Cause Cancer or Reproductive Toxicity. Office of Environmental Health Hazard Assessment. February 25, 2022. https://oehha.ca.gov/proposition-65/proposition-65-list


More Must Read Stories

Thirdhand Smoke Harms Health Around the World

Thirdhand smoke has increasingly become a global concern. Recently, three independent research studies conducted in Turkey surveyed participants about the topic of thirdhand smoke. Each of these studies adds to the mounting body of evidence that thirdhand smoke is a prevalent issue around the world and requires widespread policy and educational action to address.

Read More »

Why focus on exposure to thirdhand tobacco smoke and not exposure to auto exhaust or industrial pollution?

There are many pollutants that can contaminate our environments. Presently, vehicle emissions and industrial air pollutants receive much-needed attention from policy makers and the public. But there remains a lot of important work to be done to protect environments from other forms of pollution, such as pollutants from tobacco smoke. A focus on tobacco smoke exposure draws attention to a source of pollution that is the result of preventable activities that can be easily changed or eliminated.

Read More »

Recent Articles

Grubby little hands touched the wall!

Children’s Hands Can Tell us if They were Exposed to Thirdhand Smoke

A recent study from San Diego State University suggests that nicotine on the hands of children is one of the most effective ways to measure children’s thirdhand smoke exposure over time and in different environments. In collaboration with colleagues at Cincinnati Children’s Hospital, the researchers

Share This
Tweet This
Email This

Stay Informed

Get the latest thirdhand smoke news and research delivered straight to your inbox, or follow us on social media: