Suggesting that current non-smoking regulations may not be enough to minimize nonsmokers' exposure to thirdhand cigarette smoke, researchers report that concentrations of nicotine and smoking-related volatile organic compounds spiked when moviegoers entered a well-ventilated, non-smoking movie theater, exposing them to the equivalent of between one and 10 cigarettes of secondhand cigarette smoke. This is the first study to demonstrate real-time thirdhand smoke emissions in an indoor nonsmoking environment, the authors say, and while their case study takes place in a movie theater, the results are broadly applicable to a range of indoor environments worldwide. Roger Sheu et al. conclude that chemicals associated with cigarettes entered the theater by way of smokers' clothing and bodies, with especially high concentrations of smoking-related volatile organic compounds like toxic benzene and formaldehyde detected during late-night and R-rated films, when attendance is lower but the proportion of adults is higher. Previous research provides conclusive evidence for the harmful health effects of smoking--no level of exposure is considered safe. But while regulations have decreased smoking in public locations, pollutants from tobacco smoke remains a health hazard, especially for infants and children. Thirdhand exposure by inhaling evaporated gases or dusts that settle on surfaces after smoking, or from touching or ingesting the cigarette-related dust on surfaces, has been identified as part of this health threat. To observe how these chemicals are transferred from people to a nonsmoking environment, Sheu and colleagues used mass spectrometry to measure tracers of smoke in an empty non-smoking movie theater, before guests arrived, and as attendees took their seats. They also considered the impact of vaping. "Electronic cigarettes are not sources of most of the compounds we report here, and we did not observe enhancements in chemicals specifically concentrated in vaping emissions," says Drew Gentner, a researcher on the study. "However, we identify thirdhand vaping as a key area for future research. For example, we did see a lot of nicotine, which is present in vaping products. So nicotine from e-cigarettes could have also been transported by people and off-gassed in the theater."