Thirdhand smoke an invisible danger within many public settings, scientists warn

NEW HAVEN, Conn. — It’s common knowledge that second-hand smoke and the hazardous chemicals cigarettes contain are harmful. A recent study by Yale University however, finds the problem is even worse. Researchers say thirdhand smoke can be dangerous as well.

Third-hand smoke occurs when smokers carry the dangerous compounds of cigarettes on their bodies and clothes into non-smoking environments. Described as residual contamination, it usually comes from cigarette smoke adhering to walls and surfaces where smoking has previously occurred.

There are already measures in effect that deal with the dangers of thirdhand smoke in some areas. Hotels and rental cars restrict smoking to avoid contaminating odors and harmful chemicals from affecting non-smokers.

Smoking has long-lasting effects on settings

Research shows even if someone is in a room in which no one has smoked, they can still be exposed to some of the hazardous chemicals found in cigarette smoke if a recent smoker has been there.

“In real-world conditions, we see concentrated emissions of hazardous gases coming from groups of people who were previously exposed to tobacco smoke as they enter a non-smoking location with strict regulations against indoor smoking,” says Drew Gentner in a university release. “People are substantial carriers of thirdhand smoke contaminants to other environments. So, the idea that someone is protected from the potential health effects of cigarette smoke because they’re not directly exposed to secondhand smoke is not the case.”

Invisible dangers indoors

To test the theory, the associate professor of chemical and environmental engineering used highly sensitive instruments to track thousands of compounds inside a movie theater for a week. The report finds that the range of volatile organic compounds (VOCs) increase when certain people enter a theater.

One pattern reveals VOC increases are minor during G-rated movies, but audiences for R-rated movies appear to release much larger quantities of VOCs. The researchers suggest this is because audiences for R-rated movies are more likely to be around smoke or the viewers smoke just before entering the theater. By analyzing the proportions of these VOCs in the theater, the researchers confirm that they come from slightly-aged cigarette smoke.

The amounts of these hazardous chemicals are large enough to affect personal health, according to the Yale team. The gas emissions are the same as exposure from one to ten cigarettes worth of secondhand smoke in one hour.

Open spaces do little to stop thirdhand smoke

Those emissions and air concentrations of VOCs also spike when audiences arrive in the theater and decrease over time however, these chemicals never truly dissipate even after the audience leaves. Study authors say this is because the chemicals penetrate into the many surfaces and furnishings inside the cinema; similar to the way thirdhand smoke contaminates spaces where someone smokes.

Avoiding movie theaters is not the solution to avoid third-hand smoke, the researchers emphasize. The theater the team tested was a large, well-ventilated space which reduces VOC concentrations. Poorer ventilated areas, like buses, bars, or offices have much higher concentrations of harmful compounds brought in by smokers.

The study was published in the journal Science Advances.

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Ben Renner

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