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.
To better your chances of buying a smokefree used car, follow these steps.
1. Ask questions:
- Did the owner ever smoke or vape in the car?
- Did the owner let others smoke or vape in the car
2. Inspect the vehicle:
- Do you smell stale tobacco smoke or excessive fragrance that could be covering up an odor?
- Do you see any stains on the upholstery or burn marks on the seats or floor?
3. Consider the asking price:
- Does it seem “too good to be true?”
If you answered “yes” to any of these questions, the car is likely polluted with thirdhand smoke. In most cases, it is impossible to remove the toxic thirdhand smoke chemicals from a car. Consider buying a different vehicle.
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. Thirdhand smoke 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.
When people smoke in a car, thirdhand smoke residue builds up just the way it does in indoor environments. However, a car is a much smaller space, so the concentration of tobacco smoke chemicals is higher. This build-up happens even if the car’s ventilation system is on or the windows are open.
In addition, a car’s interior contains more materials and surfaces, such as floor carpeting, seat fabrics, upholstery, and ceiling liners, that can absorb toxic tobacco residue. Once absorbed, these chemicals cannot be completely removed from the materials, and they can re-emit into the air and settle in dust in the car. Even if a car’s interior is cleaned frequently, the tobacco residue will remain in reservoirs embedded in the fabrics and upholstery. In addition, even if someone smokes only outside of the car, they can transfer thirdhand smoke into the car on their hands, skin, hair, and clothes.
Before you “sign on the dotted line,” take these steps to help you determine if a prior owner allowed smoking inside the vehicle.
- Ask about prior smoking in the vehicle.
Actively engage the seller in a discussion about prior smoking in the vehicle. If you are speaking with the owner, ask these two questions:
- Did you ever smoke or vape in this car?
- Did you ever let others smoke or vape in this car?
Similarly, if you are speaking with a dealer, you should ask these questions:
- Did you ask the previous owner about smoking and vaping?
- If not, can you find out if the previous owner ever smoked/vaped or allowed smoking/vaping in the car?
- When you prepared the car for sale, did you notice any smell or other signs of tobacco use?
Although asking is essential, it’s important to recognize that owners are not required to disclose previous smoking, and a dealer may not know about the previous owners’ smoking history.
- Inspect the vehicle.
Get inside, close the doors and windows, and conduct your own inspection.
- First, smell. The odor of stale tobacco smoke means thirdhand smoke has accumulated in the vehicle.
- Be cautious if you smell strong air fresheners or heavily perfumed upholstery cleaners. It is not uncommon for a seller to use air fresheners or fragrances to disguise unpleasant odors. If you smell fragrances, ask why the seller is using them.
- Look for stains, another sign of tobacco smoking in the car. Check along the edges of car panels or the ceiling liner for discoloration.
- Check the seat covers and flooring for signs of small burns that could indicate accidentally dropped cigarettes or fallen ashes.
- Be cautious of a great deal.
If the price is “too good to be true,” it just might be. The resale value is lower for cars that have been smoked in. An owner or dealer might offer a low price in order to sell the vehicle quickly.
Going through these steps to ensure your vehicle is clean of toxic thirdhand smoke residue will not only protect your health but also the health of those who ride in it.
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 March 2025
Sources:
Continente X, Henderson E, Lopez-Gonzalez L. et al. Exposure to secondhand and thirdhand smoke in private vehicles: Measurements in air and dust samples. Environmental Research. 2023;235. doi: 10.1016/j.envres.2023.116681
Fortmann AL, Romero RA, Sklar M, et al. Residual tobacco smoke in used cars: Futile efforts and persistent pollutants. Nicotine & Tobacco Research. 2010;12(10):1029-36. doi: 10.1093/ntr/ntq144
Matt GE, Fortmann AL, Quintana PJ, et al. Towards smoke-free rental cars: An evaluation of voluntary smoking restrictions in California. Tobacco Control. 2013;22(3):201-7. doi: 10.1136/tobaccocontrol-2011-050231
Matt GE, Quintana PJ, Hovell MF, et al. Residual tobacco smoke pollution in used cars for sale: Air, dust, and surfaces. Nicotine & Tobacco Research. 2008;10(9):1467-75. doi: 10.1080/14622200802279898
Matt GE, Romero R, Ma DS, et al. Tobacco use and asking prices of used cars: Prevalence, costs, and new opportunities for changing smoking behavior. Tobacco Induced Diseases. 2008;4:2. doi: 10.1186/1617-9625-4-2
Jacob P 3rd, Benowitz NL, Destaillats H, et al. Thirdhand smoke: New evidence, challenges, and future directions. Chemical Research in Toxicology. 2017;30(1):270-294. doi: 10.1021/acs.chemrestox.6b00343.
Pitten L, Brüggmann D, Dröge J, et al. TAPaC—Tobacco-associated particulate matter emissions inside a car cabin: Establishment of a new measuring platform. Journal of Occupational Medicine and Toxicology. 2022;17. doi: 10.1186/s12995-022-00359-x
