研究発表

The reduction of energy consumption in the Japanese residential sector is a pressing issue because of climate change. However, an excessive reduction in air conditioner use to save energy could create a poor sleep environment. Therefore, the purpose of this research was to elucidate the impact of air conditioning on both energy consumption and sleep during the summer. Eight healthy male university students participated in this study, which was conducted in August 2013. Three thermal environmental control scenarios were used: natural draft, air conditioner set at 26.0 °C (continuous operation), and air conditioner set at 28.0 °C (continuous operation). Energy consumption, indoor thermal environment, and sleep state were measured during the experiment. The energy consumption for using an air conditioner for 8 h was reduced by 0.03 kWh/day/m2 by increasing the temperature setting from 26.0 to 28.0 °C. Furthermore, the range of the average standard new effective temperature during sleep was from 27.6 to 31.4 °C (the average temperature during sleep was from 26.5 to 29.8 °C) where both energy saving and high-quality sleep were achieved. The results of this study indicate lifestyle changes are possible that allow both energy saving and high-quality sleep.

Field measurements were conducted in a nursing home located in the hot and humid city of Kumamoto, Japan, between July and September 2010. In addition, a questionnaire survey was conducted with care staff during the measurement procedure to evaluate the effect of the thermal environment on thermal comfort and productivity. Results indicated that radiant cooling and heating system provided a stable temperature. Furthermore, the system coefficient of performance was calculated to evaluate the performance of the radiant cooling system and was 1.8-3.1. As a result of the questionnaire survey, about half of the staff were satisfied with the current thermal environment in the facility, reporting that it was comfortable and did not reduce working efficiency.

In Japan, 50 % of heatstroke patients transported to hospital by ambulance are elderly. Most cases of heatstroke in the elderly occur at home. Accordingly, this study aimed to determine the relationship between the indoor thermal environment and body temperature as a critical cause of heatstroke in the elderly. A field survey comprising actual measurements and a questionnaire survey was conducted in summer 2015. The night-time standard new effective temperature (SET*) was found to be higher in multi-unit houses than detached houses, and was higher on the top floor than middle and lowest floors. Furthermore, the sublingual temperature increased by 0.03 °C per 1.0 °C increase in night-time SET*. These results will help proposals aimed at reducing the risk of heat stroke in the elderly.

Improvement of living environment quality of life (QOL) is increasingly attracting attention as a factor in disease prevention. We administered questionnaires to adult residents of a suburb of Kitakyushu City, Japan, in October 2009 and October 2011, with the aim of evaluating chronological changes in resident health and changes in the housing and regional environment over those two years. Cause-and-effect relations were considered through structural equation modeling (SEM) using a cross-lagged effects model and a synchronous effects model. Analysis of the results indicates that the housing and regional environment affects resident health. The present study quantified living environment value according to reported resident satisfaction. In addition, further studies with an increased sample size may be beneficial. Topics for future research include evaluation using objective indicators to strictly elucidate the causal relationship between resident health and living environment.

Since the primary due period of 2008-2012 of the Kyoto Protocol Target Year is close at hand, specific measures for the prevention of global warming should be implemented in all areas. This paper outlines the energy consumption and greenhouse gas emission trends in the residential and commercial sectors in Japan. The paper presents the projections of CO2 emissions until 2050. The projections indicated that if the various energy conservation measures were implemented, up to 59% of reduction in CO2 emissions against the 1990 level can be achieved. The paper also describes political measures in energy conservation, including the building energy conservation standard, Comprehensive Assessment System for Building Environmental Efficiency (CASBEE), top-runner programs, financial incentives, and the dissemination of Cool Biz concept.

This research describes the effects of injecting rigid polyurethane foam into walls and fitting double glazing or inner panes to sash windows as simple renovation methods for houses, based on estimations of CO 2 emissions from heating/cooling and LCCO 2 (Life Cycle CO 2). We estimated CO 2 emissions and LCCO 2 up to 2020 in Japan and obtained the following results. (1) Injecting rigid polyurethane foam into walls in detached houses, where there is little thermal insulation, reduces the LCCO 2 significantly. (2) In regions with mild climates like Tokyo, renovating windows brings higher LCCO 2 reductions in houses insulated to 1992 Criteria for the Rational Use of Energy in Houses 1) than in those insulated to conventional levels or the 1980 criteria. (3) When choosing one of the two methods above, we should take into account the initial insulation level, the house structure, and the region. (4) Domestic CO 2 emissions for houses in Japan can be reduced by 13% to 19% by 2020 with the use of simple renovation methods for thermal insulation.

Human physiology dictates that the sole temperature drops by touching a cold floor in a poor insulation, whereupon the peripheral temperature receptor stimulates the sympathetic nervous system, leading to an increase in Blood Pressure (BP) due to vasoconstriction. Furthermore, flooring material affects perceived thermal sensation. This study aims to analyse the relationship between floor temperature, flooring material and BP. 10 healthy male university students and 13 middle-aged men participated in this study, which was conducted in October 2015. The floor temperature was 21.2 °C in a well-insulated room compared with 17.2 °C in an uninsulated. In the younger, the average BP was insensitive to floor temperature. In the older, however, BP rose by about 3.7 mmHg with solid wood flooring and by about 7.5 mmHg with vinyl after an hour in the uninsulated. Despite this, a significant difference in BP elevation was not confirmed between floor materials.

With the recent reduction in physical activity seen in Japanese children, reduced ability to exercise and increasing prevalence of overweight and obesity have become serious health concerns. Therefore, governmental agencies have promoted the improvement of the regional environment to encourage physical activity in children. This study shows, using a questionnaire survey and actual measurement of physical activity of children and parents, that the frequency at which children use community centers and gyms and participate in community activities affects frequency of exercise. The number of daily steps in children who did not receive sufficient daily exercise (<10,000 steps/day) increased by about 3,000 steps/day when they participated in community activities.

Sleep problems can have profound economic and health effects. Recently, the effect of the indoor thermal environment on sleep has attracted attention. However, the relationship between the indoor thermal environment and sleep, by season, has not been fully studied. Accordingly, the purpose of this study was to elucidate the effect of the indoor thermal environment on sleep in both summer and winter. Field studies comprising actual measurements and questionnaire surveys were conducted during summer 2013 and winter 2014. Statistical analysis of the data yielded the following main results. First, sleep efficiency, defined as the ratio of total sleep time to total time in bed, was highest at a bedroom temperature of 27.6 °C in summer and 13.0 °C in winter. Second, after controlling for personal attributes, sleep efficiency decreased by 3.2% per 1 °C increase in bedroom temperature over 27.6 °C in summer, and by 0.3% per 1 °C below 13.0 °C in winter.

We have conducted field measurements and a questionnaire survey, and statistical analysis of the results, in order to review applicable criteria for assessing the thermal environment in school classrooms without air conditioning. From survey results for both summer and winter, we found that the indoor-outdoor temperature difference is more strongly correlated with students' thermal sensations in classrooms than the predicted mean vote index: the correlation coefficient is 0.979 in summer and -0.992 in winter. These results indicate that the indoor-outdoor temperature difference is a valid criterion for assessing the thermal environment of classrooms. In addition, taking the indoor-outdoor temperature difference as the explanatory variable and the index of the students' thermal sensations as the objective variable, we performed a logistic regression analysis. As a result, formulas for predicting students' thermal sensations in classrooms were derived. These findings should be beneficial in establishing an appropriate learning environment for students.

Recently, the effects of the indoor thermal environment on blood pressure have attracted attention. However, these effects have not been studied in relation to personal factors, particularly individual attributes and lifestyle. Therefore, the purpose of this research is to analyze the relation between indoor temperature and blood pressure while taking into account personal factors. Field surveys on home blood pressure, indoor temperature, and personal factors were conducted in winter 2012 and 2013. Controlling for personal factors, systolic blood pressure increased by 4.3 mmHg per 10 °C decrease in indoor air temperature. Also, a 1 °C decrease in indoor air temperature increased 1.12-fold the likelihood of a reading above 135 mmHg (the standard value of systolic blood pressure at home). Furthermore, the effect of indoor air temperature was stronger in residents with more severe arteriosclerosis. Therefore, residents at high risk of cardiovascular events should keep the indoor thermal environment within an appropriate range.

Various researches highlight that indoor air quality affects performance of workers in offices1). Although good indoor air quality improves work performance, it also increases energy consumption. In this study, we achieved a field survey in a real office in order to investigate the relationship between thermal environment, productivity, and energy consumption. In addition to the monitoring of indoor environmental quality and energy consumption, subjective experiments were conducted. In order to evaluate subjective performance, workers and students responded to questionnaires, and to evaluate objective performance, students simulated three types of office works. By calculating room temperature and worker's subjective performance, we demonstrate the correlation between room temperature and worker's performance (R=0.45, p<0.01). Results show that the room temperature that maximizes worker's performance was 25.6°C. It was also estimated that the equivalent 'quantity of work' of 8-hour work per day at 25.6°C can be achieved with minimum energy consumption in an environment where the room temperature is 27.3°C.

To create the desired Japan 2050 future, it will be one of the most effective measures that architects and engineers can easily use the life cycle assessment (LCA) and life cycle costing (LCC) methods in the basic or schematic design phase of each building. Author has been developing the "Comprehensive Assessment System for Building Environmental Efficiency (CASBEE)", supported by the Japan Ministry of Land, Infrastructure and Transport. In this keynote speech, several sustainable buildings designed and assessed by author to create the desired Japan 2050 future will be presented as follows: "Head office of the Institute for Global Environmental Strategies (IGES)", "Head office of the Japan Aerospace Exploration Agency (JAXA)", "Liberty Tower of Meiji University", "Yusuhara Town Hall".

Many previous studies have shown that the urban environment may affect human health directly or indirectly. However, those studies have primarily focused on particular aspects of the urban environment and lack an overall perspective. Therefore, this study aims to clarify and identify the urban elements having strong relationships with human health from a broader standpoint. To achieve this goal, multivariable analysis was conducted to determine the relationship between each urban element and resident life expectancy, using data from a comprehensive, nationwide assessment of whole cities in Japan. The results show that the life expectancies of males and females are affected by different urban elements and that moving toward healthier cities will require taking these differences into account.

In Japan, the number of deaths from bathing-related heat stroke has increased rapidly over the last few years. Bathwater temperature and bathing duration have a major impact on body temperature, and extreme changes in body temperature can result in death. However, safe bathing habits have not been fully studied. Therefore, an existing human physiological model was extended to accurately predict body temperature during bathing. Furthermore, data from a field survey conducted in the 2012-2013 winter were analyzed and bathing habits were found to be affected by room temperature. The results of this study will be useful for promoting safe bathing habits that accommodate individual differences and show that heating of bathing-related rooms is recommended for preventing heat stroke due to bathing.

In households, residents should understand the actual conditions of energy usage in order to increase the effectiveness of energy-saving actions. Accordingly, the "Low-Carbon Home Consulting System" was developed in this research. First, the energy consumption and lifestyle of residents were identified through a questionnaire survey. Then, the system was developed based on the survey results. Energy consumption broken down by usage was estimated with this system. Finally, the energy savings were estimated. In this way, the CO2 emissions of individual households were reduced by up to approximately 40% relative to the emissions prior to applying the developed system. This study demonstrates that, by facilitating effective energy-saving actions, energy consumption and CO2 emissions can be reduced while maintaining a healthy environment for residents.

The health damage caused by indoor air pollution has become serious nowadays, and studies of solutions are improving in medical and building science respectively. However, to solve this problem fundamentally, comprehensive and quantitative assessments, from generation of pollutants to start of symptoms, are needed. In this study, damage-function of indoor air pollution is calculated with Disability Adjusted Life Year (DALY).It becomes possible to quantitatively assess the health damages from indoor air pollution, and a number of environmental issues can also be assessed at the same time.