Life cycle assessment of Cigarette from cradle to grave: Identifying environmental hotspots and end-of-life scenario analysis

Cigarette smoking and its negative health effects are well documented; however, the environmental impacts of cigarettes are poorly understood. Moreover, considering cigarette butts (CBs) as one of the most littered items globally, exploring the relative environmental effects of different end-of-life (EoL) pathways is essential to design effective mitigation strategies. So, the objective of this study is to identify the environmental hotspots across the cigarette lifecycle—both upstream and downstream of consumption—and to compare the environmental impacts of three potential EoL pathways of the CBs using a comprehensive cradle-to-grave life cycle assessment (LCA). The results depicted that cigarette manufacturing accounted for the highest environmental impact (98.36%) among the upstream processes of the cigarette life cycle. Especially human carcinogenic toxicity emerged as the highest potent impact category (0.168 kg 1,4-DCB), followed by freshwater eutrophication (0.0014 kg P eq.) and freshwater ecotoxicity (0.0525 kg 1,4-DCB) for a single cigarette production. Additionally, the cigarette consumption phase also depicted the highest environmental impacts contributing to human carcinogenic toxicity (96.3%), primarily due to the release of hazardous air pollutants during smoking. Further, the relative environmental impacts of three EoL scenarios were analysed for a CB—incineration, littering and landfilling disposal. Among the EoL scenarios analysed, littering of CBs caused the highest environmental impacts, mainly due to the leaching of toxic contaminants into water bodies. Despite evidence that CBs contain over 150 highly toxic chemicals with carcinogenic and mutagenic properties, the lack of detailed, standardized databases for these substances limits the precision of environmental impact analyses. Future research should address this gap by developing comprehensive databases and standardized methodologies to incorporate the specific contaminants in CBs. Such advancements are essential for a more accurate and holistic evaluation of the environmental pollution associated with CB disposal and to guide effective mitigation strategies.