Persistent Emission of Volatile Organic Compounds From Thirdhand Cigarette Smoke-Contaminated Paper and Cloth

Thirdhand smoke (THS) is the complex mixture of cigarette smoke chemicals that linger in the environment after cigarettes are smoked. Research has shown that the majority of semi-volatile organic compounds released during smoking stick to indoor surfaces before they can be removed by ventilation.  This “tar” can react with ambient air to create new chemicals, some of which are volatile and re-enter the air.  To identify the volatile organic compounds (VOCs) released from THS-contaminated surfaces, we exposed paper, 100% cotton cloth and 100% polyester cloth to secondhand cigarette smoke.  The materials were exposed in a stainless steel exposure chamber, for 163 hours over 110 days.  After the exposure, half the samples were stored in amber glass vials at -20 C.  The others were placed on a shelf in the laboratory and allowed to react and desorb or “air out” under ambient conditions for 42 days.  Control samples were not exposed to smoke and were treated in parallel.  The VOCs emitted by the samples were then identified and quantified using real-time proton-transfer reaction mass spectrometer (PTR-MS).   Our results show that the samples emitted a broad spectrum of VOCs, including acetonitrile, furan, toluene, formaldehyde, acetaldehyde and acrolein.  The samples that had desorbed for 42 days at room temperature still emitted VOCs at levels well above the control samples that had not been exposed to smoke. We conclude that THS may be a significant source of VOC exposures indoors and that VOC emissions from THS persist for months after the last cigarette.