How can I be exposed to thirdhand smoke?

Watch a video that answers this question here.

The Short Answer:

Thirdhand smoke is the chemicals left behind when someone smokes tobacco. Thirdhand smoke is unhealthy for people and pets. It can stick around for a long time in homes and cars. It gets into your body if you inhale, swallow, or touch the chemicals. Getting rid of it is really hard and can cost a lot of money.

People can be exposed to thirdhand smoke by:

  1. Absorbing thirdhand smoke residue through their skin when touching polluted objects or surfaces, such as floors, rugs, or blankets. 
  2. Breathing in thirdhand smoke chemicals and particles that are released into the air from surfaces.
  3. Swallowing thirdhand smoke residue when putting polluted objects, such as silverware or toys, in their mouths. Teething children are at high risk for this.

A woman holds her head. Images of skin, lungs, and a mouth show how thirdhand smoke can enter the body.

The Long 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.

There are three main ways that people can be exposed to thirdhand smoke.


People can be exposed to thirdhand smoke when their skin comes in contact with a polluted surface. These include the steering wheel of a car, clothes, blankets, toys, and furniture. Thirdhand smoke in the air can also stick to your skin.  Some of the thirdhand smoke chemicals can enter your body through the skin, get into your bloodstream, and circulate through your body. They can harm your DNA, immune system, and cardiovascular system. If you think you have touched surfaces contaminated with thirdhand smoke, wash your hands immediately.


People can breathe in thirdhand smoke chemicals and particles suspended in the air. Thirdhand smoke can be released into the air from surfaces such as clothing, furniture, carpets, walls, or pillows. When this happens, we can sometimes smell stale tobacco smoke – but not always. When you smell stale tobacco smoke, it is not just a foul odor. It is a mixture of toxic chemicals that enters your body through your lungs. If you do not smell stale tobacco smoke, that does not necessarily mean there is not any thirdhand smoke present because some thirdhand smoke chemicals are odorless.

Entering the Mouth

People can swallow thirdhand smoke when they put objects polluted with thirdhand smoke, such as utensils, cups, toys, or fingers, into their mouths. Young children are at the highest risk of swallowing thirdhand smoke because they put many objects in their mouths, particularly when teething.

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: February 2024


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Matt GE, Quintana PJ, Zakarian JM, Fortmann AL, Chatfield DA, Hoh E., et al. When smokers move out and non-smokers move in: Residential thirdhand smoke pollution and exposure. Tob. Control. 2011; 20. e1 10.1136/tc.2010.037382.

Matt GE, Merianos AL, Stone L, Wullenweber C, Quintana PJE, Hoh E, et al. Changes and stability of hand nicotine levels in children of smokers: Associations with urinary biomarkers, reported child tobacco smoke exposure, and home smoking bans. Environ Int. 2023;181:108239. Epub 20230927. doi: 10.1016/j.envint.2023.108239. PubMed PMID: 37852151

Matt GE, Merianos AL, Quintana PJE, Hoh E, Dodder NG, Mahabee-Gittens EM. Prevalence and Income-Related Disparities in Thirdhand Smoke Exposure to Children. JAMA Network Open. 2022;5(2):e2147184-e. doi: 10.1001/jamanetworkopen.2021.47184.

Jacob P, Benowitz NL 3rd, Destaillats H, Gundel L, Hang B, Martins-Green M, et al. Thirdhand smoke: New evidence, challenges, and future directions. Chem. Res. Toxicol. 2017; 30:270–294. 10.1021/acs.chemrestox.6b00343.

Tang X, Benowitz N, Gundel L, Hang B, Havel CM, Hoh E, Jacob P, Mao Jian-Hua, Martins-Green Manuela, Matt GE, Quintana PJ, Russell M, Sarker Altaf, Schick S, Snijders A, and Destaillats H. Thirdhand Exposures to Tobacco-Specific Nitrosamines through Inhalation, Dust Ingestion, Dermal Uptake, and Epidermal Chemistry. Environ. Sci. Technol. 2022;

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