Volatile organic compound exposure from environmental tobacco smoke: Assessing secondhand and thirdhand hazards on non-porous inorganic surfaces

Abstract

Herein, to assess the potential exposure risks to volatile organic compounds (VOCs) by environmental tobacco smoke (ETS), field experiments have been carried out to measure VOCs emitted as secondhand smoke (SHS) and thirdhand smoke (THS) from standard 1R6F cigarettes in a controlled smoking booth (33.8 m3). The most dominant VOCs released from SHS samples are isoprene (446 ppb) > 1,3-butadiene (203 ppb) > methyl ethyl ketone (27.1 ppb) > toluene (23.4 ppb) > benzene (16.5 ppb), while those released from THS are 1,3-butadiene (9.04 ppb) > toluene (8.02 ppb) > benzene (3.71 ppb) > isoprene (2.90 ppb) > phenol (1.63 ppb). High-concentrations of compounds common to both SHS and THS (e.g., 1,3-butadiene, isoprene, and benzene), with SHS/THS ratios greater than unity, suggest a process of strong emissions during active smoking, followed by accumulation on surfaces, and moderate, sustained re-emission as THS. Incremental lifetime cancer risks (ILCRs) associated with THS are estimated at 2.38 × 10−6 for 1,3-butadiene and 6.20 × 10−6 for benzene, both exceeding the commonly accepted risk threshold of 1 × 10−6. In contrast, SHS-related ILCRs are not found to surpass this threshold. The findings of this study provide better insights into the relative contributions of SHS and THS exposure for better management of indoor air quality and public health.