Journal of the Human-Environment System
Online ISSN : 1349-7723
Print ISSN : 1345-1324
ISSN-L : 1345-1324
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Showing 1-4 articles out of 4 articles from the selected issue
  • Masahiro Hori
    Type: review-article
    2020 Volume 23 Issue 1 Pages 1-11
    Published: 2020
    Released: September 20, 2020
    JOURNALS FREE ACCESS

    This review describes the definition of TVOC, measuring method, biological influence, standard value, effect and the defect, significance of existence and how to use it. The process for which TVOC has been used as an indoor environment quality index is also explained. TVOC was proposed as an index which showed the possibility of the pollution influence. It was also proposed as the overall, simple notation of VOCs of which many kinds existed in the indoor air. TVOC has been used in a lot of the research. However, the defect as the index that showed the contaminated level was pointed out by existence of small amount stimulus ingredients missed by a present VOC/TVOC measuring method. TVOC can’t be a toxic academic index essentially. On the other hand, because a lot of VOCs coexists, to which the standard value is not set yet, TVOC has the practical meaning as an environmental protection index to achieve the decrease of the VOC risk through the monitoring of VOC concentration and the evaluation of source such as construction materials.

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  • Kahori Genjo
    2020 Volume 23 Issue 1 Pages 13-29
    Published: 2020
    Released: September 20, 2020
    JOURNALS FREE ACCESS

    A questionnaire survey on both the lifestyle and energy consumption of 626 university students in Tohoku region was conducted in 2007 and 2008 to assess energy conservation behaviors and energy consumption in one-person student households. This study aims to clarify the influence of each lifestyle factor that would affect the energy consumption of one-person student households. Of the 626 respondents, 344 one-person households and 215 family households were analyzed via the method of quantification theory type I, as the explanatory variables were roughly divided into hard and soft factors. In this study, the hard factors are considered to be the age of the building, the space heating and cooling period, the set point temperature of space heating appliances, heat source of hot water supply, and the set point temperature of hot water in winter. The soft factors are considered to be the degree of action of the energy conservation behavior in the house, consciousness of global environmental issues, consideration for energy conservation in daily life, and the degree of energy conservation efforts.

    The following conclusions of this study were obtained: 1) It was found that the heat source of hot water supply and set point temperature of hot water supply in winter were important factors that have a great impact on the annual utility costs among the six hard factors used in the analysis in one-person student households and family households, respectively. 2) Space cooling period had clear association with the annual utility costs in one-person households, whereas space heating period had clear association with the annual utility costs in family households. 3) The annual utility cost of one-person student households was greatly influenced by how to use appliances and energy conservation efforts. 4) The tendency of the partial correlation coefficients of soft factors to be higher in family households than those of hard factors was stronger than that of one-person households. 5) Differences in energy conservation efforts and consciousness of global environmental issues among family households were greatly reflected in annual utility costs compared to one-person households. 6) The effect of the degree of action of energy conservation behavior in the house on the annual utility costs was found to be greater or comparable to that of the hard factors including how to use equipment in both one-person households and family households. 7) It was shown that the correlation with the annual utility costs is higher when considering not only hard factors but also soft factors in both one-person households and family households. 8) It is important not only to save energy, but also to confirm that the indoor thermal comfort is secured in one-person households.

    Since the number of one-person households is expected to increase in the future in Japan, the findings of this study are expected to be useful to promote energy conservation nationwide by developing energy-conservation techniques for one-person households. At the same time, energy conservation measures should be developed that take into account the importance of lifestyle-related factors depending on the household type.

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  • Satoru Takada
    2020 Volume 23 Issue 1 Pages 31-43
    Published: 2020
    Released: September 20, 2020
    JOURNALS FREE ACCESS

    To create an optimal indoor thermal environment, it is necessary to identify the environmental conditions that cause a sensation of dryness. Dryness is experienced in various parts of the human body such as the nose, mouth, throat, eyes, and skin: this study focuses on dryness in the airway. The relationship between the sensation of dryness and environmental factors such as the ambient air temperature and humidity (vapor pressure) was analyzed based on experiments performed on four subjects. This study analyzed the sensation of dryness experienced in six parts along the respiratory tract and the temperature of air inhaled/exhaled at the airway aperture of each of the four subjects under different conditions of humidity and temperature maintained in an artificial climate chamber. The route of respiration was restricted to the nose or the mouth by blocking the other aperture. The experimental results revealed that the temperature of exhaled air was lower and the sensations of dryness in the nose, mouth, and throat were more intense in the case of low humidity under a constant temperature. These results suggest that an increase in the evaporation rate in the airway may cause a sensation of dryness. Further, the experimental results revealed that in the case of high temperature and constant vapor pressure, the sensation of dryness tended to be more intense. This suggests that higher ambient temperature increases the evaporation rate in the airway owing to the increase in the saturated vapor pressure in the inner surface of the airway.

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  • Chihiro Miwa, Hiroya Shimasaki, Masayasu Mizutani, Yasunori Mori, Kazu ...
    2020 Volume 23 Issue 1 Pages 45-53
    Published: 2020
    Released: September 20, 2020
    JOURNALS FREE ACCESS

    The purpose of this study was to clarify the effects of bathing on thermoregulatory and subjective responses in elderly persons compared to those in young persons. Ten young (20.4 years) and 10 elderly (69.7 years) individuals were asked to bathe for 15 minutes in water at 41 °C. Tympanic temperature (Tty) was measured using a thermometer with a thermistor, sweating rate (SR) was measured by a ventilated capsule method, and skin blood flow (SkBF) was measured by laser Doppler flowmetry to assess thermoregulatory responses. Subjective thermal and comfort sensations were evaluated using a seven-point scale. The results showed significant increases in Tty, SR and SkBF in young participants than in elderly participants. In addition, we divided the total bathing period into three time periods and observed later SR and SkBF responses in elderly participants than in young participants. While young participants felt hot and unpleasant during the late time period, elderly participants felt warm and comfortable during the entire duration of bathing. These results demonstrate the thermoregulatory responses due to changes in physical structure and function due to aging during a 15-minute bath at 41 °C in the elderly.

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