Many Children Still Exposed to Tobacco Smoke Pollution Even in 'Smoke-Free' Homes

Handwipe tests detect nicotine exposure among 95% of tested children, with sharply higher levels found among lower-income families. Experts in Cincinnati and San Diego say findings indicate need for widescale efforts to reduce thirdhand smoke exposure

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Cincinnati Children's Hospital Medical Center

Feb 07, 2022, 11:00 ET

CINCINNATI, Feb. 7, 2022 /PRNewswire/ -- The person who smoked a pack a day may have moved out years ago, but the toxic substances left behind stuck around. And to this day, the particles that settled deep into furniture, carpets--even the drywall--remain available to be picked up and adsorbed by growing children.

Melinda Mahabee-Gittens, MD, MS, and Georg Matt, PhD

In fact, more than 95% of children living in homes considered smoke-free carry detectable levels of nicotine on their hands, which means a stew of toxicants found in tobacco smoke is finding its way into growing kids even though parents are trying to keep the smoke out. That's the surprising new finding about thirdhand smoke published Feb. 7, 2022, in JAMA Network Open, by researchers at Cincinnati Children's and San Diego State University.

No level of exposure to tobacco pollution is considered "safe" for kids. But the research team has just begun the work needed to match up thirdhand smoke exposure levels to specific health outcomes—a task that will take years.

"This is the first part of a much larger study," says corresponding author Georg Matt PhD, a professor at San Diego State and Director of the Thirdhand Smoke Resource Center. "We are publishing the first part because it was so stunning how widespread the exposure issues are."

Melinda Mahabee-Gittens, MD, MS, a long-time tobacco hazards researcher at Cincinnati Children's, oversaw the medical testing.

"We had performed a similar study involving kids from smokers' homes, and as we expected, we found nicotine on nearly all the kids' hands," she says. "In this study, we expected the exposures in smoke-free homes to be near zero, but they were not."

Findings Further Illustrate Health Risks Faced by Low-Income Families

This study compared results from handwipe tests between 311 children living in homes considered "protected" from smoke exposure to 193 living in "exposed" conditions. Unsurprisingly, nicotine was found on 98% of the children living in exposed conditions. However, nicotine also was found on 95% of "protected" children.

Overall, testing found about 3 nanograms per wipe among children in non-smoking homes. But researchers found about 14 nanograms per wipe among children in the lowest-income group. Such results exceed the levels found in higher-income homes where people are smoking.

"This study is another example of income-related health disparities," Matt says. "The people with the least resources are also least able to afford newly built smokefree housing, the least able to replace old smoke-embedded carpets and couches with new ones, and the least able to influence what neighbors do in multiunit buildings or how landlords maintain them."

Findings Sharpen Focus on Indoor Pollution Hazards

Thirdhand smoke exposure refers to the particles that settle upon surfaces after—and stay there. That smell of stale smoke isn't just obnoxious, the researchers say. Over time tobacco smoke particles become embedded in carpets and furniture and can remain a risk for years.

Children touching contaminated surfaces can ingest particles by placing their fingers in their mouths. The particles can be inhaled through a process known as off-gassing. The particles also can be absorbed directly through the skin, Mahabee-Gittens says.

Previous studies have shown that children living with active smokers have increased risk of asthma exacerbations, reduced ability to fight infections, and increased risk of developing pneumonia.

Known tobacco residue risks also include DNA-damaging organic chemicals and toxic effects from various heavy metals--including lead. This, in turn, indicates that years of indoor smoking have been partially undermining efforts in many cities to reduce old lead-based paint hazards.

"The big difference is that you cannot buy lead paint anymore. People still smoke, so the smoke pollution is ongoing," Matt says.

These new findings suggest that America's tobacco habit poses lingering indoor pollution hazards to children of non-smokers, not just the children of smokers.

"We live in an environment that is coated with this legacy of tobacco use," Matt says. "All we can do is raise awareness. It's not just a harmless unpleasant odor, it's a potent mixture of pollutants that you should not expose your children to."

Next steps

Researchers have started work to build upon these findings. Cincinnati Children's seeks to enroll up to 1,000 children in a clinical study to gather more data about exposure levels, housing conditions and health outcomes.

In the meantime, families can take steps to minimize thirdhand smoke exposure. Recommendations include enforcing smoking bans in homes and cars, discarding old carpets and furniture exposed to smoking, controlling dust as much as possible, and asking about smoking histories when moving to a new residence or buying a used car.

"If you are living in a home where you know people have smoked, it would be good to find out more. Was this really a home where someone smoked a pack a day for the last 20 years? If that's the case, I personally would move out," Matt says. "But not everyone has that choice."

SOURCE Cincinnati Children's Hospital Medical Center