The issue of marine pollution caused by micro-plastics has emerged and has attracted worldwide attention. If the source of micro-plastic is routine plastic waste and products, they will be located very close to the living environment, and there is a concern about the risk of micro plastic contamination even in the residential environment. However, the actual micro plastic conditions of the indoor environment, and the presence or absence of micro-plastic contamination in residential environments, as well as their concentrations, have not been well investigated so far. In this study, we firstly classified and defined micro-plastic present in indoor environment, and proposed a standard sampling and measurement method of indoor micro-plastic concentration by way of a preliminary field survey in residential houses.

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Chemical exposures are typically investigated by measuring the actual concentration of exposure. However, due to time and cost constraints, actual exposure concentration measurements are not always possible; hence, there is an increased demand for model estimation. Meanwhile, many semivolatile organic compound model predictions have not accurately reproduced the measured fractions of gas- and particle-phase concentrations in air. In this study, in order to improve the reproducibility of the fraction of phase concentration in air by the exposure model, the suspended particle diameter, which is one of the parameters affecting the particle-phase concentration, was optimized. Our comprehensive literature research on the interaction between gaseous di (2-ethylhexyl) phthalate and the suspended particle found that the representative value of aerodynamic diameters of PM10 for the particle-phase concentration were 0.375μm. By optimizing the particle diameter, the estimated fraction of gas-phase concentration improved from 58% to 29%, thereby approaching the measured fraction of 10%-20%. Although the Factor value, which denotes the estimation accuracy of total air concentration, shifted by 64% to the safe side from 2.8 to 4.6, the screening accuracy remained adequate. Furthermore, the higher tier assessment accuracy for the estimated concentration of settled dust was maintained.

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O-(2,3,4,5,6-Pentafluorobenzyl)hydroxylamine(PFBHA), is known to react with aldehydes to produce oxime derivatives. Due to this chemical property and the stability of the products formed, PFBHA could be practically used in sampling devices to measure aldehydes in exhaled breath. In this study, we aimed to develop a novel active sampler to measure aldehydes in the human exhaled gas, using a silica gel tube which had been previously applied for the sampling of indoor aldehydes. A novel silica gel based sampler was created by filling a glass tube with PFBHA-coated silica gel. The collection efficiency, lower limit of detection, lower limit of quantification, repeatability, recovery and storage stability of the novel sampler were examined for 12 aldehydes,: formaldehyde, acetaldehyde, acrolein, propanal, butanal, pentanal, 2-methylpentanal, hexanal, heptanal, octanal, benzaldehyde and nonanal. Our results showed that the novel sampler had a good efficiency for sampling, good repeatability with 5.3 % relative standard deviation, and good recovery with 90-116 % in each test. The lower limit of quantification for each aldehyde was in the range of 1.1-3.7 ng/100 mL in exhaled breath. Moreover, this developed silica gel tube was practically applied to exhaled gas from healthy volunteers and prostate cancer patients, and useful findings were successfully obtained. Thus, PFBHA-coated silica gel tubes can be used as sampling devices for human exhaled aldehydes.

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[in Japanese]

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Here, we characterized the current predicament of indoor pollution in Japan by conducting a literature search that included the author's report on the real state of indoor pollution emanating from chemical substances released from sources such as combustion appliances, building materials, and household goods. We found that, following the establishment of the indoor guidelines, indoor pollution tended to improve, partly in combination with the progress of various administrative measures. However, there have been reports of unregulated substances other than the guideline values being used in construction materials, household good, teaching materials, and so on, thus posing health hazards. Further research on unregulated substances will be required in the future as will the cooperation of member professors in guiding the unregulated substances.

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Open combustion appliance is a device which utilizes oxygen in indoor air to combust fuels and releases an exhaust gas into indoor air. It is used for cooking, heating and hot-water supply in a residential house. Especially, there is a great demand for kerosene space heaters in a cold region or cold days. However, we have to care the chemical substances in the exhaust gas, which potentially have adverse health effects by inhalation. In this paper, after reviewing the principles on the generation of air pollutants from open type devices were described focusing on carbon monoxide (CO), nitrogen oxides (NOx) and volatile organic compounds (VOCs). Additionally, importance of indoor air quality monitoring was mentioned by demonstrating the field survey on the indoor air pollution by “invisible” NOx.

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Wood, kerosene, coal, natural gas, liquefied petroleum gas (LPG), and biomass have been used as mainly fuels for cooking and heating in our daily life. Health effects of indoor air pollutants emitted by combustion of their fuels are very serious, in particular, low- and middle-income countries, and then the urgent actions are required. World Health Organization (WHO) estimated that household air pollution was responsible for an estimated 3.2 million deaths per year in 2020, including over 237,000 deaths of children under the age of five. In this paper, the basic characteristics, main emission sources, and health effects of typical indoor air pollutants emitted by combustion, including particulate matters (PM₁₀, PM_2.5), carbon monoxide, nitrogen oxides, sulfur dioxide, polycyclic aromatic hydrocarbons (mainly, benzo[a]pyrene), and volatile organic compounds (benzene, formaldehyde) are summarized. In addition, the latest WHO air quality guidelines for those compounds are also summarized.

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