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Particles from decades-old cigarette smoke can make kids sick, new Children's study shows

a man smokes a cigarette
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Wikimedia Commons

A new study, publishedby researchers at Cincinnati Children’s Hospital Medical Center,
finds children in "smoke-free" homes can still feel the effects of nicotine that has clung to walls and carpet for years.

Thirdhand smoke refers to the particles that settle out from the exhaled smoke and coat surfaces.

This thirdhand smoke can increase the risk of respiratory and infectious illnesses, including asthma, bronchiolitis and pneumonia. It can also damage the DNA within the cells of exposed tissue, the study says.

Children are ingesting the particles by getting them on their fingers and then putting their fingers in their mouths. Thirdhand smoke chemicals can also be absorbed directly through the skin on their hands.

Not all homes are equal

The study, published in Monday’s JAMA Network Open, says there are sharp disparities along economic lines for children exposed to thirdhand smoke.

Children in the lowest income families (where parents made less than $15,000) had higher levels of nicotine particles on their hands, totaling 14 nanograms per wipe in non-smoking homes. This compares to less than 3 nanograms per wipe from the highest income homes (above $120,000)

Because the findings were so concerning scientists published this study early

“This is the first part of a much larger study that looks at clinical outcomes," says Georg Matt, Ph.d, director of the Thirdhand Smoke Resource Center at San Diego State, which collaborated on the research. "We are publishing the first part because it was so stunning how widespread the exposure issues are.”

No level of exposure to tobacco pollution is considered “safe” for kids.

“We had performed a similar study involving kids from smokers’ homes and as we expected, we found nicotine on nearly all the kids’ hands," says Melinda Mahabee-Gittens, MD, MS, a member of the Division of Emergency Medicine at Cincinnati Children’s and a long-time researcher of the impact of tobacco pollution exposure. "In this study, we expected the exposures in smoke-free homes to be near zero, but they were not.”

Ashley Merianos, Ph.d., an assistant professor of health promotion and education at the University of Cincinnati is a co-author.

What can be done?

It will likely take years to see community-wide actions. “We live in an environment that is coated with this legacy of tobacco use,” Matt says. “All we can do is raise awareness and make sure people understand what they are doing. It’s a potent mixture of pollutants that you should not expose your children to.”

Here are some steps people can take even if policy changes remain years away:

  • Make sure you have a strict smoking ban in your home—and your car.
  • Control dust by regularly wiping surfaces. Use vacuums that have HEPA filters.
  • Frequent washing with regular detergents will remove thirdhand smoke residue from toys, clothing and bedding, but not carpets and old couches.  
  • Avoid hand-me-down furniture.
  • Replace old carpet; steam cleaning is not effective as a long-term treatment.
  • If you live in multiunit housing, learn and seek enforcement of building smoking policies.
  • Advocate for smoking bans in your building.
  • When moving, ask about the smoking history of your potential new residence.

Mahabee-Gittens is continuing to study the issue. She is leading a clinical trial to enroll another 400 children mostly from non-smoking homes to learn more about how health measures vary across differing levels of thirdhand smoke exposure.

For information, send an email to or call 513-218-0517.

Ann Thompson has decades of journalism experience in the Greater Cincinnati market and brings a wealth of knowledge and expertise to her reporting.