Because of the health effects of secondhand smoke, the Japanese government is trying to establish an effective law for total avoidance of secondhand smoke in indoor environments for tobacco-free Tokyo Olympic and Paralympic games 2020, as requested by the International Olympic Committee (IOC) and the World Health Organization (WHO). Meanwhile, Philip Morris International has begun selling a new heat-not-burn tobacco, iQOS, which it claims is designed not to produce secondhand smoke. There is little scientific data, however, of the hazards and toxicity of iQOS. In this study, we evaluated several harmful compounds (nicotine, tar, carbon monoxide (CO) and tobacco-specific nitrosamines (TSNAs)) in the mainstream smoke and fillers of iQOS, and compared their concentrations with those from conventional combustion cigarettes. The concentrations of nicotine in tobacco fillers and the mainstream smoke of iQOS were almost the same as those of conventional combustion cigarettes, while the concentration of TSNAs was one fifth and CO was one hundredth of those of conventional combustion cigarettes. These toxic compounds are not completely removed from the mainstream smoke of iQOS, making it necessary to consider the health effects and regulation of iQOS.

Electronic cigarettes (e-cigarettes) are advertised as being safer than tobacco cigarettes products as the chemical compounds inhaled from e-cigarettes are believed to be fewer and less toxic than those from tobacco cigarettes. Therefore, continuous careful monitoring and risk management of e-cigarettes should be implemented, with the aim of protecting and promoting public health worldwide. Moreover, basic scientific data are required for the regulation of e-cigarette. To date, there have been reports of many hazardous chemical compounds generated from e-cigarettes, particularly carbonyl compounds such as formaldehyde, acetaldehyde, acrolein, and glyoxal, which are often found in e-cigarette aerosols. These carbonyl compounds are incidentally generated by the oxidation of e-liquid (liquid in e-cigarette; glycerol and glycols) when the liquid comes in contact with the heated nichrome wire. The compositions and concentrations of these compounds vary depending on the type of e-liquid and the battery voltage. In some cases, extremely high concentrations of these carbonyl compounds are generated, and may contribute to various health effects. Suppliers, risk management organizations, and users of e-cigarettes should be aware of this phenomenon.

Carbonyl compounds in E-cigarette smoke mist were measured using coupled silica cartridges impregnated with hydroquinone and 2,4-dinitrophenylhydrazine, followed by high-performance liquid chromatography. A total of 363 E-cigarettes (13 brands) were examined. Four of the 13 E-cigarette brands did not generate any carbonyl compounds, while the other nine E-cigarette brands generated various carbonyl compounds. However, the carbonyl concentrations of the E-cigarette products did not show typical distributions, and the mean values were largely different from the median values. It was elucidated that E-cigarettes incidentally generate high concentrations of carbonyl compounds.

As a new form of cigarettes, heated tobacco products (HTPs) have been rapidly distributed worldwide. In this study, an improved method for analyzing gaseous and particulate compounds generated from HTPs is described. Smoke is collected using a GF-CX572 sorbent cartridge with 300 mg of carbon molecular sieves, i.e., Carboxen 572 (CX572), and a 9 mm glass-fiber filter (GF). After collection, the CX572 particles from the cartridge are transferred along with the GF and deposited into a vial containing two phases of carbon disulfide and methanol. The CX572 particles settle into the lower carbon disulfide phase, while nonpolar compounds are desorbed. After allowing the sample to stand, the solution is slowly stirred. The two-phase mixture of carbon disulfide and methanol is combined into a homogeneous solution. Polar compounds are then desorbed, while the desorbed nonpolar compounds remain in solution. For the analysis of carbonyl compounds, an enriched 2,4-dinitrophenylhydrazine solution is added to a portion of the combined solution for derivatization and subsequent high-performance liquid chromatography analysis. For the analysis of volatile organic compounds and water, a portion of the combined solution is analyzed by gas chromatography–mass spectrometry or equipped with a thermal conductivity detector. By applying the proposed GF-CX572 one-cartridge method to the analysis of the mainstream smoke generated from HTPs and traditional cigarettes, several chemical compounds are detected, and the chemical composition of smoke is revealed. The GF-CX572 one-cartridge method can analyze gaseous and particulate chemical compounds from the HTP smoke by utilizing not only the entire puff volume but also one puff volume because the GF-CX-572 cartridge can be replaced with a new cartridge within 3 s. An overview of the chemicals generated from HTPs is obtained in detail by one-puff volume sampling. In addition, the generated chemical compounds strongly depend on the temperature of tobacco leaves in HTPs.