Smoking microplastics: Global evidence of microplastic contamination in cigarette tobacco

Microplastics (MPs) are recognized as emerging contaminants with potential respiratory risks. Although cigarette filters are known contributors to environmental MP pollution, the tobacco portion has not been investigated as a direct source of inhaled plastic-derived particles during smoking. This study investigates the occurrence and characteristics of MPs in the unburned tobacco component of commercially available cigarettes, providing evidence of a previously overlooked source of potential exposure during smoking. A global sample of cigarette packs was obtained from retail sources in 18 countries. Tobacco from each pack was processed using a modified alkaline oxidation and oxidative cleanup procedure to isolate plastic particles. MPs were identified in 83 of 88 samples. Concentrations ranged from 1.58 to 29.9 particles per gram of tobacco, with a mean of 7.20 (±0.97). Fragments were most common, followed by fibers. Polymer analysis revealed that polyethylene, polypropylene, and polyethylene terephthalate dominated, while polyamide, polycarbonate, and other polymers were also detected. Significant differences in MP abundance were observed among countries and among major producers. MPs are present in the tobacco of most commercially sold cigarettes, indicating an overlooked source of plastic-derived particle exposure during smoking. The identification of polymers known to release harmful combustion byproducts highlights a potential additional inhalation hazard for smokers. These findings support the need to include MP contamination in the evaluation and regulation of tobacco product safety.