We evaluated the effect of three types of household deodorizers (Product-A, Product-B, and Product-C) on indoor air quality by measuring indoor ozone (O₃) and nitrogen oxides using the developed ozone detection paper and porous glass analytical chip. The average O₃ concentration in the vicinity of the air outlet of each household deodorizer was 2.60 ± 0.25 ppm, which was 50 times higher than the WHO guideline value (0.05 ppm) for Product-A and Product-B, and 0.5 times higher than the WHO guideline value for Product-C. Concerning the nitrogen dioxide (NO₂) concentration, for which indoor environmental standard values have been established, Product-C had a maximum concentration of 30 ppb, which was less than the guideline values (0.1 ppm and 0.06 ppm) set by the WHO and the school environmental health standard of Japan, while Products-A and -B had concentrations of 810 ± 235 ppb, which was 8 times larger than the WHO guideline value. Furthermore, the average O₃ concentration emitted from Product-B decreased with distance z^－0.60, and no accumulation of concentration with operating time was confirmed. The average NO₂ concentration decreased at z^－0.42 and z^－0.70 relative to the distance z in the measurements in November 2020 and January 2021, respectively, suggesting the influence of diffusion due to indoor environmental conditions.
Although the use of products-A and -B was not considered to cause accumulation of O₃ and NOx concentrations, the concentrations around the air outlets exceeded the standard values, and there was concern about the deterioration of indoor air quality. For Product-C, both O₃ and NO₂ concentrations were below the guideline values.

View full abstract

Background research into the legacy of disease and death that cigarette smoking imposes on the health of the population is extensive. It has become obvious that smoking causes various health problems, and that not only smokers but also non-smokers are affected by secondhand smoke, which is a major public health problem. In response to health concerns about the harmful health effects of smoking, the tobacco industry has begun to market new tobacco products, such as heated Tobacco product (HTP), as Modified Risk Tobacco Products (MRTP) to traditional cigarettes. The investigations on HTP were carried out only by the producing company and its competitors in those years. Their studies concluded that HTP emissions were less harmful than cigarette smoke. However, there is a report for a case of acute eosinophilic pneumonia that developed after switching from conventional cigarette smoking to HTP smoking, and HTP can rapidly and substantially impair the cardiovascular system in rats comparably to smoke from a cigarette. Moreover, there is a report that prenatal exposure to HTP adversely affects the male testicular function of the offspring more than smoke from conventional cigarettes. This article objectively reviews the potential effects of HTP on human health and the environment by searching and integrating the published research manuscript. In this review, I begin with a brief discussion of the research trends of HTP, followed by the introduction of impact on several diseases compared to the conventional cigarette. Moreover, the last section is devoted to the challenges and future research directions.

View full abstract

The impact of combustible cigarettes on active and passive smokers has become a medical and social problem. In recent years, heated tobacco products (HTPs) have been available in Japan. HTPs are tobacco products in which the user inhales the aerosol produced by heating the tobacco. HTPs do not produce secondhand smoke from combustion and are therefore expected to reduce the adverse effects on human health. However, the health impact of HTPs has not been fully understood. Recent studies reported that HTPs have basically reduced levels of some chemicals, compared to combustible cigarettes; however, several chemicals have been reported to be increased in HTP. Because of the insufficient scientific evidence, there is concern about the long-term effects of exposures to HTPs. To understand the relationship between cigarette smoking and cancer, we have investigated the component of cigarette smoking using cancer stem cells, which give rise to many types of cancer. We identified that nicotine and NNK can induce the proliferation of human cancer stem cells. We also found that tobacco smoke extracts from HTPs induce the proliferation of cancer stem cells. It is necessary to identify other chemicals in tobacco smoke extracts from HTPs to understand the health risk of the long-term use of HTPs.

View full abstract

In response to the growing health consciousness of smokers and the amended Health Promotion Law, which was fully enforced in April 2020, the number of users of heated tobacco products (HTPs) is increasing. Along with market expansion, competition for the development of HTPs has intensified, and the types of heating devices and their tobacco sticks have been increasing every year. HTPs reduce the amount of chemicals in mainstream smoke, but there is little evidence for health risks to active and passive smokers. The ISO (International Organization for Standardization) method and the HCI (Health Canada Intense) method are used as standard methods for chemical analysis of mainstream smoke generated from combustion cigarettes. For HTPs, CORESTA (the Cooperation Center for Scientific Research Relative to Tobacco) has published the technical report (Heated Tobacco Product-259-CORESTA technical report) for the collection of mainstream smoke in July 2020. This review outlines the characteristics and types of HTPs, puffing protocols for chemical analysis, and the biological effects of mainstream smoke generated from HTPs.

View full abstract

Heated tobacco product is a device which delivers nicotine into body by inhaling the mainstream aerosol generated during direct and/or indirect heating tobacco processes. The generated aerosol mainly consists of "water droplets", so that is different in physical and chemical property to conventional cigarette smoke. The novel media is being marketed as less hazardous than conventional cigarettes in Japan. However, the adverse health effects of inhaled and/or exposed aerosols should be further evaluated considering the difference in the physical and chemical property. Possible by-formation products should be also concerned because the novel tobacco employs the heating system of glycerin and propylene glycol to produce the water droplets. This paper reviewed the physical and chemical aspects of the mainstream aerosol of the heated tobacco products and discussed the formation of chemical components and behavior in indoor environment.

View full abstract