What is thirdhand smoke, and why is it a concern?

Answers from Lowell Dale, M.D.

Thirdhand smoke is generally considered to be residual nicotine and other chemicals left on a variety of indoor surfaces by tobacco smoke. This residue is thought to react with common indoor pollutants to create a toxic mix. This toxic mix of thirdhand smoke contains cancer-causing substances, posing a potential health hazard to nonsmokers who are exposed to it, especially children.

Studies show that thirdhand smoke clings to hair, skin, clothes, furniture, drapes, walls, bedding, carpets, dust, vehicles and other surfaces, even long after smoking has stopped. Infants, children and nonsmoking adults may be at risk of tobacco-related health problems when they inhale, ingest or touch substances containing thirdhand smoke. Thirdhand smoke is a relatively new concept, and researchers are still studying its possible dangers.

Thirdhand smoke residue builds up on surfaces over time and resists normal cleaning. Thirdhand smoke can't be eliminated by airing out rooms, opening windows, using fans or air conditioners, or confining smoking to only certain areas of a home. Thirdhand smoke remains long after smoking has stopped. In contrast, secondhand smoke is the smoke and other airborne products that come from being close to burning tobacco products, such as cigarettes.

The only way to protect nonsmokers from thirdhand smoke is to create a smoke-free environment, whether that's your private home or vehicle, or in public places, such as hotels and restaurants.

Mar. 20, 2012