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.

Babies and young children are at the greatest risk of exposure to thirdhand smoke. The best way to prevent exposure to thirdhand smoke is to ensure that your child’s home is 100% smokefree.

That means no smoking or vaping tobacco, e-cigarettes, or cannabis at any time inside your home or anywhere else your child spends time. This includes homes of friends and family, hotels, restaurants, entertainment venues, and childcare.

Here are additional steps you can take to keep thirdhand smoke out of your child’s environment.

In your home: 

• Remember that smoke can drift into your home, so do not allow anyone to smoke outside near doors, windows, or ventilation systems.
• Before renting an apartment or buying a new home, ask questions about previous residents’ use of tobacco, e-cigarettes, and cannabis. 
• Before bringing something used into your home, 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.

• Before someone who smokes visits your home, explain that when people smoke, thirdhand smoke residue sticks to their clothes, hands, face, body, and hair. Then, ask them to wash their hands, shower, and change into clean clothes before spending time in your home or with your child.  

In someone else’s home:

• Do your best to ensure that all adults who spend time with your child are 100% smokefree, especially childcare workers. 
• If your child spends time with someone who smokes, have them wash their hands and face and change their clothes before seeing your child.

• If you cannot avoid your child spending time somewhere that may contain thirdhand smoke, when your child comes home, have them shower and change into clean clothes.

If you believe that a home is polluted with thirdhand smoke:

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, you may need a complete renovation. 

• 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) daily vacuuming with a HEPA filter.
• If you have washable items that came from a home where someone smoked, such as clothes, toys, or blankets, thoroughly wash them or consider discarding them. For fabrics, we recommend three rounds of washing and drying to ensure that the toxic pollutants have been completely removed.
• Remember that it is nearly impossible to remove thirdhand smoke from walls, carpets, HVAC systems, and other large housing structures. If your home is polluted with thirdhand smoke, you will likely have to renovate and replace these.
• When moving into a new home, always ask if previous residents smoked and about the building’s smoking policies. If possible, choose a new home that has not been smoked in and a property that has a strict indoor smoking ban.

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 2025

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