Lingering cigarette smoke carried on the bodies and clothing of cinema-goers could present a health risk to non-smokers, scientists have warned.
Previous studies have suggested this so-called “third-hand smoke” could account for between 5% and 60% of the combined disease burden from cigarette smoke in non-smokers.
Dr Drew Gentner, co-author of the research from Yale University, said the latest study shows third-hand smoke represents significant but poorly understood health risks to non-smokers and a source of reactive chemicals indoors.
The researchers tracked traces of cigarette smoke in a German cinema, which was 1,300 sq metres in size and supplied with fresh, filtered air from outside.
Researchers at a cinema in Germany
detected 35 volatile substances in the air found in tobacco smoke, including
formaldehyde and the carcinogenic chemical benzene
The team sampled the exhaust air duct of the cinema for four days and detected 35 volatile substances that are found in tobacco smoke, including formaldehyde and the carcinogenic chemical benzene.
Concentrations of such substances showed a spike when customers entered the screening.
Less pronounced spikes were seen for earlier show times and levels of the substances were lower for family films than for “R-rated” action films aimed at older cinemagoers, despite the latter having smaller audiences.
“In the R-rated films, especially the ones that are occurring later in the evening, it appears there’s a greater propensity of people attending those movies to have smoked, or perhaps to have smoked more frequently or more cigarettes, and so they are off-gassing more,” said Gentner.
The team found signs that substances from third-hand smoke build up over time because the chemicals don’t remain entirely in the air, but are also absorbed on to various surfaces and furnishings from which they re-enter the air over time, the Guardian reports.
The researchers also collected samples of fine, airborne particles from the cinema and analysed the substances stuck to them. Among those detected was nicotine.
They found that people going to R-rated films were exposed to the equivalent of second-hand smoke from between one and 10 cigarettes, depending on the substance in question.
Prof John Britton, director of the UK Centre for Tobacco and Alcohol Studies and consultant in respiratory medicine at Nottingham University, said that in reality the exposure sustained by others in such circumstances is low and any health risk likely to be likewise, however he called for more research into potential impacts.
The study was published in the journal Science Advances.