Dosimetry in the lungs of -particles (210Po) and -particles (210Pb) present in the tobacco smoke of conventional cigarettes and heated tobacco products

Tobacco products contain radioactive 210Pb and 210Po which can be transferred from the filler to the mainstream smoke. When inhaled, they can contribute to the radioactive dose to the lungs and are suspected to significantly contribute to lung cancer from smoking. Currently, no data are available on the radioactive risk of the heated tobacco products (HTP). However, due to the relatively high heat involved in some of these devices, there are concerns about the volatility of polonium particles.Here we used data on the 210Po and 210Pb content in tobacco smoke along with biokinetic and dosimetric models to compute the effective dose induced by conventional smoking and by using an HTP device (PMI IQOS system). Results show that conventional smoking of one pack per day induces a dose to the lung of about 0.3 mSv/year. This dose decreases by a factor of ten (0.03 mSv/year) for the IQOS system. However, this dose reduction is not obtained by specific countermeasures but by the fact that the IQOS system heats only 15% of the tobacco filler to the target temperature of 330 degrees C. When heated homogeneously to 300 degrees C, both conventional and Heets (IQOS) cigarettes release about 80% of the 210Po from the tobacco, leading to similar doses to lungs.