New Yale study rekindles debate over dangers of third-hand smoke
A new study is offering the most comprehensive real-world demonstration of how volatile organic compounds (VOCs) can spread throughout indoor environments from cigarette smokers’ clothing and bodies. Often referred to as third-hand smoke, the research tracked spikes of tobacco-related VOCs in a non-smoking cinema over four days, however, the health risks from this kind of exposure are still unclear.
Decades of research have pretty rigorously explored the health effects of first and secondhand exposure to cigarette smoke. Over the last 15 years a new form of exposure to cigarette-related toxins, called third-hand smoke, has been characterized by scientists. Third-hand smoke refers to toxins that can be emitted, or “off-gassed,” from the bodies or clothes of cigarette smokers.
Increasingly sophisticated environmental monitoring methods have allowed scientists to detect these smoking-related VOCs in greater detail than ever before. And this new study, a collaboration between Yale University and the Max Planck Institute for Chemistry, is the first real-time environmental study to show how levels of these VOCs can rise and fall in an indoor non-smoking environment.
The study chronicles four days of real-time air measurements in a well-ventilated German cinema. A high-resolution mass spectrometer was installed in one theater’s ventilation duct, tracking the rise and fall of 35 particular VOCs previously associated with third-hand tobacco smoke.
Across the study period the researchers detected spikes of tobacco-related VOCs, including 2,5-dimethylfuran, 2-methylfuran, and acetonitrile, coinciding with arrival and departure times of moviegoers. While these temporal spikes in environmental VOCs could be interpreted as simply related to general groups of people entering and exiting an indoor space and bringing toxins in on their clothes from outside, the research revealed major differences in VOC volumes depending on the film content and time of day.
Spikes of tobacco-related VOCs were significantly elevated during late-night sessions and R-rated movie screenings, compared to lower volumes detected with similar audience sizes during early G-rated screenings. So, although the study did not specifically determine how many smokers were in any particular session, the researchers are confident this datapoint implies the observed rise in VOCs could be linked to third-hand smoke.
"We had a really great set-up where we were conveniently sampling from the exhaust air duct right after the air left the theater, so we were able to measure the average chemical composition of the air in the theater without disturbing the occupants," says Drew Gentner, an author on the new study. "We did not expect the off-gassing of chemicals from residual tobacco smoke on people to be such a prominent source of reactive chemicals into the room.”
The research comprehensively shows VOCs such as benzene, acrolein, formaldehyde, and nicotine, can be released from the clothes and bodies of smokers into an indoor environment. But, the study makes no claims about health risks in relation to the volume of VOCs detected.
Experts not affiliated with this new study suggest the research is no cause for concern. John Britton, who is director of the UK Centre for Tobacco and Alcohol Studies, was not at all surprised with the results of this study, noting the levels of VOCs detected were so low it is unlikely they would result in significant health risks.
“This study confirms what anyone with a sense of smell has already worked out: that smokers carry and emit tobacco smoke components into the atmosphere even when not smoking,” Britton said to The Guardian. “In reality the exposure sustained by others in such circumstances is low, and any health risk likely to be likewise.”
The researchers claim the the amounts of VOCs detected in the study were not trivial. In fact, the published journal entry clearly states in its abstract the VOC emissions detected are equivalent to several cigarettes of secondhand smoke.
“These VOC emission events exposed occupants to the equivalent of 1 to 10 cigarettes of secondhand smoke, including multiple hazardous air pollutants (e.g., benzene and formaldehyde) at parts-per-billion concentrations,” the researchers write in the journal entry.
The new research was published in the journal Science Advances.
Source: Yale University