Numerous studies have shown that environmental tobacco smoke (ETS) is causally associated with health effects that are as harmful as those of active smoking (Health and Services, 2006). The harmful chemical components of cigarettes are absorbed into the human body and adversely affect not only those individuals who smoke themselves but also others around them through various routes (Health and Services, 2006). Secondhand smoke (SHS) refers to the simultaneous inhalation of mainstream or sidestream smoke by others as a result of active smoking. In general, ETS has been used as a synonym for SHS.

Studies of exposure assessment for ETS have been typically conducted through observation, questionnaire, air sampling, or biological sampling (Florescu et al., 2009). Many studies have adopted questionnaires to assess personal exposure to ETS, which has the advantage of being able to easily evaluate large populations at low cost. However, it is difficult to objectively quantify ETS exposure with questionnaires due to recall bias and other sources of error (Chen et al., 2002, Florescu et al., 2009, Rebagliato, 2002). Although methods using biological samples from blood, hair or urine are the most accurate for person-level ETS exposure assessment, biomarkers can be affected by exposure to tobacco in various ways. Therefore, directly measuring nicotine in the air as an environmental indicator is a complementary method to objectively assess potential exposure to tobacco.

Indoor ETS is affected by several factors, with the room size and proximity to active smoking being the most influential. When substances in cigarettes are released through smoking, the airborne concentration per unit area is inversely related to the room size. Additionally, the exposure to a greater concentration of the substances is likely when in closer proximity to a pollutant of indoor tobacco substances especially with poor ventilation (Apelberg et al., 2013).

In addition, research in exposure to third-hand smoke (THS) has further increased interest in passive smoke in recent years. THS refers to the residual pollutants absorbed on indoor walls, curtains, and sofas long after smoking is concluded, and then re-emitted. These substances are known to persist for months to years or more (Matt et al., 2011, Sleiman et al., 2014). Furthermore, existing research has shown that passive smoke can occur even when tobacco smoking is not accompanied by cigarette combustion (simultaneous or otherwise). The toxic substances in cigarettes are primarily produced by combustion, but even without combustion, they can become sufficiently airborne and affect the human body.

During harvesting and weaving of tobacco, for instance, the nicotine in tobacco leaves is absorbed into the body through the skin, causing dizziness, headaches, and vomiting among tobacco farm workers (Fassa et al., 2014, Schmitt et al., 2007). Yoo et al. have shown that (Yoo et al., 2014) airborne nicotine concentrations collected from outdoor tobacco fields and samplers attached to non-smoking farmers working outdoors were found to have higher concentrations compared to indoor environments such as bars, video/computer game rooms and internet cafes where active smoking occurs (Yoo et al., 2014). Moreover, indoor workplaces like tobacco curing barns exhibited significantly higher concentrations than outdoor tobacco fields. These findings were attributed to the diffusion of nicotine into the air from cigarettes themselves, rather than from the combustion of the cigarettes.

In sum, although many ETS studies have been conducted on the airborne spread of nicotine via passive smoking, most of such studies have only studied the spread of tobacco chemicals due to active combustion (e.g., Active smoking). Otherwise, the existing research has only examined the specific context of tobacco farms, where high nicotine concentrations are expected to occur. Despite being designated as non-smoking areas, cases of unintended exposure to passive smoking in the workplace continue to be revealed due to third-hand smoke and the dispersion of smoking substances in the air (Matt et al., 2014; Park et al., 2021).

Our understanding of passive smoking resulting from packaged cigarettes has been limited which poses potential risk for low-level exposure as it is often unnoticed without combustion. To the best our knowledge, no studies have been conducted on the spread of airborne nicotine in point-of-sale, tobacco retailer contexts. Convenience stores in South Korea serve both as workplaces for workers and public spaces heavily visited by customers. Given that even minimal exposure to smoking can pose risks to human health, and considering there is no identified safe threshold for exposure, the objective should be to minimize exposure as much as possible (Society, 2023) and the matter of low-concentration passive smoking exposure is emerging as a novel challenge (Sim and Park, 2021).

The current study aims to examine the extent to which uncombusted and packaged cigarettes stored in cigarette racks at retail stores diffuse airborne nicotine. Our hypotheses for this study are as follows: H1) detectable levels of nicotine will be passively released from cigarette racks at tobacco retailers in the absence of active combustion. H2) the nicotine will diffuse into the indoor air with the higher concentration at more proximal locations to the cigarette racks within the store.