Quantification of Flavors, Volatile Organic Compounds, Tobacco Markers, and Tobacco-Specific Nitrosamines in Heated Tobacco Products and Their Mainstream Aerosol

As an alternative to cigarettes, the sales of heated tobacco products (HTPs) have increased in the Japanese market. This may contribute to improving a smoker's health because the levels of most toxic compounds─such as tobacco-specific nitrosamines (TSNAs) and volatile organic compounds (VOCs)─in the mainstream of HTPs are lower than those in cigarettes. However, the risks associated with the flavors that provide attractive tastes to HTPs remain unknown. We demonstrated that compared with cigarettes, HTPs reduce the health risks associated with VOCs and TSNAs while achieving comparable nicotine and flavor levels. The VOC and TSNA concentrations in the mainstream aerosol of HTPs were 0.0039 (benzene)-0.53 (acetaldehyde) times lower than those in cigarettes. Using HTPs may still pose adverse noncarcinogenic and carcinogenic effects on human health, as indicated by hazard quotients >1 for acrolein and acetaldehyde, margins of exposure <100 for (<i>R</i>)-(+)-limonene, and cancer risks >1.0 × 10^-6 for acetaldehyde. Additionally, the exhalation of mainstream aerosol may increase the indoor acrolein concentration to 0.069 μg m^-3, exceeding the reference concentration for acrolein (0.02 μg m^-3). Therefore, reducing acrolein concentrations is an effective measure for improving the safety of HTP use.