210Po and 210Pb content in the smoke of Heated Tobacco Products versus Conventional Cigarette smoking

Abstract 210 Po is a radioactive component of conventional cigarette tobacco smoke and is a recognized carcinogen. Despite the expanding market of heated tobacco products, no data are available on the activity of 210 Po in the smoke of IQOS Heets cigarette. We determined the 210 Po activity in the mainstream smoke of thirteen cigarette brands available on the Swiss market using a smoking machine and compared the results to the 210 Po activity measured in the mainstream smoke of the IQOS system. In addition, we measured the 210 Po and 210 Pb loss on heating after uniform heating from 50 to 600 °C for several cigarette brands and the Heets cigarettes. 13.6 ± 4.1% of 210 Po activity was found in the mainstream smoke in conventional cigarette smoking (7% for 210 Pb). This dropped to 1.8 ± 0.3% in the mainstream smoke of IQOS Heets. Conversely, when the tobacco was heated uniformly at 330 °C, a loss of 210 Po of more than 80% was observed for all type of cigarettes. Apparently, IQOS significantly reduced the 210 Po and 210 Pb activities in the mainstream smoke. However, our results show that only 15% of the Heets tobacco reaches 330 °C with IQOS. While IQOS reduces the 210 Po and 210 Pb activities in the mainstream smoke compared to conventional cigarettes, it only heats a marginal fraction of the tobacco present in the Heets cigarette. Because smoking is an addiction (mostly due to nicotine), IQOS could possibly deliver an unsatisfactory dose of nicotine to a Heets cigarette smoker, as most of the tobacco is left unaltered.