Chemometric assessment of the radiotoxic burden: 210Po in conventional, slim, and heated tobacco products.

Polonium-210 (210Po), a highly radiotoxic α-emitter from the 238U decay chain, represents an underrecognized contributor to tobacco-related health risk. Following inhalation, 210Po deposits in bronchial and alveolar regions, delivering high-LET radiation to sensitive pulmonary tissues. The present study aimed to quantify 210Po activity and its distribution across tobacco, combustion residues, filters, and mainstream smoke in conventional cigarettes, slim cigarettes, and heated tobacco products (HTPs), and to evaluate inter-product variability using multivariate chemometric approaches. Combustion-based products exhibited substantial transfer of 210Po to mainstream smoke (ca.70% on average), whereas HTPs showed significantly lower transfer (ca.15%), although absolute 210Po activities in HTP tobacco matrices remained comparable across categories. Principal component and discriminant analyses revealed partial clustering of HTPs, while conventional and slim cigarettes showed overlapping profiles, indicating limited categorical separation. Regional dose modelling based on ICRP respiratory tract assumptions demonstrated that the alveolar-interstitial compartment accounted for the largest contribution to annual effective dose. These results indicate that naturally occurring radionuclides contribute measurably to the radiological burden of tobacco use across product types and warrant systematic inclusion in toxicological risk assessment frameworks.