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.

Babies and young children are at the greatest risk of exposure to thirdhand smoke. Here are some simple steps you can take to minimize exposure in your home and car:

In the home: 

Make sure all your child’s indoor environments are 100% smokefree.

• That means no smoking cigarettes, pipes, cigars, electronic cigarettes, or marijuana at any time inside your home or anywhere else your child spends time. This includes homes of friends and family, hotels, restaurants and entertainment venues, and playgrounds.
• Remember that smoke can drift into your home, so don’t allow anyone to smoke outside near doors, windows, or ventilation systems.
• When renting an apartment or buying a new home, ask questions about tobacco, e-cigarette, and marijuana use by previous residents. Include what you learn in your overall decision process.
• Before buying something used, such as furniture or clothing, ask about tobacco, e-cigarette, and marijuana use by previous owners. If you can’t find out, factor that into your decision to purchase.

Make sure adults who spend time with your child are 100% smokefree, especially childcare workers. 

• When people smoke, thirdhand smoke residue sticks to their clothes, hands, face, body, and hair.
• Ask anyone who smokes to wash their hands, shower, and change into clean clothes before coming in contact with your child.  

It can be very difficult to remove thirdhand smoke from indoor environments, especially if the smoking took place for a long period of time. Depending on the size of the reservoir of pollutants, complete renovation may be required. If you cannot avoid your child spending time in a home that may contain thirdhand smoke, there are a few steps you can take to reduce your child’s exposure.

Tips for reducing your child’s exposure if you believe that an indoor environment is polluted with thirdhand smoke.

• People who smoke can carry tobacco residue into your home on their skin, hair, and clothes, even if they always smoke outside. Encourage them to shower and change into clean clothes when coming inside after smoking.
• If you have items that came from a smoker’s home, especially clothes, toys, rugs, or blankets, thoroughly wash them or consider discarding them. 
• You may be able to reduce thirdhand smoke in your home by (1) opening windows to air out rooms each week, (2) regularly wiping surfaces with a diluted white vinegar solution, (3) frequent dusting, and (4) weekly vacuuming with a HEPA filter.
• Regularly washing your child’s blankets, bedding, and toys.

In the car: 

Make sure your child travels in 100% smokefree cars. 

• Don’t allow any smoking in your car at any time, and don’t let your child ride with anyone who does allow smoking in their car. 
• If you are buying a used car, be sure to ask about smoking by previous owners. Thirdhand smoke is nearly impossible to remove from automobiles.

Unfortunately, it is virtually impossible to remove thirdhand smoke once it has become embedded in a car. Even aggressive cleaning will not rid the car of toxic chemicals. Young children are particularly at risk of exposure. If you cannot avoid your child riding in a car that may contain thirdhand smoke, there are a few steps you can take to reduce your child’s exposure. 

Tips for reducing your child’s exposure if you believe that a car is polluted with toxic thirdhand smoke:

• When your child is in a car polluted with thirdhand smoke, turn on the air-conditioning using the “outside air mode.” Make sure you do not simply recirculate the air in your car; this is sometimes the default setting in a car. By bringing outside air into the car using air-conditioning, you will reduce the concentration of thirdhand smoke pollutants in the air of the car.
• Do not leave the car seat in the car. Put your child’s car seat in the car only when your child will be using it. The less time the car seat is in the car, the less time it will be exposed to toxic thirdhand smoke.
• Before you put the car seat in the car, put a clean towel under the car seat. The towel will act as a physical barrier between the car’s upholstery, which contains thirdhand smoke pollutants, and the clean car seat.
• When you are finished using the car seat, remove it and the towel. Wipe the car seat with a solution of diluted vinegar and water and throw the towel into the laundry.
• As much as possible, limit the amount of time your child is in the car.
• Because children can absorb thirdhand smoke through their skin, it is a good idea to wash your child’s hands and face when the car ride is completed.

The best way to protect your child from thirdhand smoke exposure in a car is to (1) never ride in cars that have been smoked in, (2) never let anyone smoke in your car, and (3) always ask for a non-smoking rental car—if you smell tobacco odor in the rental car, ask for another.

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: September 2022

Sources:

Fortmann, A. L., R. A. Romero, M. Sklar, V. Pham, J. Zakarian, P. J. Quintana, D. Chatfield and G. E. Matt (2010). Residual tobacco smoke in used cars: futile efforts and persistent pollutants. Nicotine Tob Res 12(10): 1029-1036.

Jacob III P, Benowitz NL, Destaillats H, Gundel L, Hang B, Martins-Green M, Matt GE, Quintana PJ, Samet JM, Schick SF, Talbot P. Thirdhand smoke: new evidence, challenges, and future directions. Chemical research in toxicology. 2017 Jan 17;30(1):270-94.

Kassem NO, Daffa RM, Liles S, Jackson SR, Kassem NO, Younis MA, Mehta S, Chen M, Jacob P 3rd, Carmella SG, Chatfield DA, Benowitz NL, Matt GE, Hecht SS, Hovell MF. Children’s exposure to secondhand and thirdhand smoke carcinogens and toxicants in homes of hookah smokers. Nicotine Tob Res. 2014 Jul;16(7):961-75. doi: 10.1093/ntr/ntu016. Epub 2014 Mar 3.

Kelley ST, Liu W, Quintana PJE, Hoh E, Dodder NG, Mahabee-Gittens EM, Padilla S, Ogden S, Frenzel S, Sisk-Hackworth L, Matt GE. Altered microbiomes in thirdhand smoke-exposed children and their home environments. Pediatr Res. 2021. Epub 2021/03/04. doi: 10.1038/s41390-021-01400-1. PubMed PMID: 33654287.

Mahabee-Gittens EM, Merianos AL, Hoh E, Quintana PJE, Matt GE. Nicotine on children’s hands: limited protection of smoking bans and initial clinical findings. Tob Use Insights. 2019;12:1-6. PMID: 30728727; PMCID: PMC6351963.

Mahabee-Gittens EM, Merianos AL, Jandarov RA, Quintana PJE, Hoh E, Matt GE. Differential associations of hand nicotine and urinary cotinine with children’s exposure to tobacco smoke and clinical outcomes. Environ Res. 2021;202:111722. Epub 2021/07/24. doi: 10.1016/j.envres.2021.111722. PubMed PMID: 34297932.

Matt GE, Fortmann AL, Quintana PJ, Zakarian JM, Romero RA, Chatfield DA, Hoh E, Hovell MF. Towards smoke-free rental cars: an evaluation of voluntary smoking restrictions in California. Tobacco control. 2013 May 1;22(3):201-7.

Matt GE, Quintana PJ, Hovell MF, Bernert JT, Song S, Novianti N, Juarez T, Floro J, Gehrman C, Garcia M, Larson S. Households contaminated by environmental tobacco smoke: sources of infant exposures. Tob Control. 2004 Mar;13(1):29-37. PubMed PMID:14985592.

Matt GE, P. J. Quintana, M. F. Hovell, D. Chatfield, D. S. Ma, R. Romero and A. Uribe (2008). Residual tobacco smoke pollution in used cars for sale: air, dust, and surfaces. Nicotine Tob Res 10(9): 1467-1475.

Northrup TF, Matt GE, Hovell MF, Khan AM, Stotts AL. (2015).  Thirdhand smoke in the homes of medically fragile children: Assessing the impact of indoor smoking levels and smoking bans. Nicotine Tob Res.2016;18(5):1290-8. Epub: 2015 Aug 26. doi:10.1093/ntr/ntv174. PubMed PMID:26315474.

Northrup TF, Stotts AL, Suchting R, Matt GE, Quintana PJE, Khan AM, Green C, Klawans MR, Johnson M, Benowitz N, Jacob P, Hoh E, Hovell MF, Stewart CJ. Thirdhand smoke associations with the gut microbiomes of infants admitted to a neonatal intensive care unit: An observational study. Environ Res. 2021;197:111180. Epub 2021/04/19. doi: 10.1016/j.envres.2021.111180. PubMed PMID: 33865820; PMCID: PMC8187318.