Published papers

Vernacular architectures exhibit high environmental performance. In this study, we evaluate the environmental performance of vernacular architectures quantitatively and comprehensively through CASBEE in order to promote sustainable buildings. On the basis of this intention, we analyzed the indoor environment of vernacular architectures from the perspective of environmental engineering by taking on-site measurements and using CFD numerical analysis. In this study, we focused our attention on Water Housing in Malaysia. The result of evaluating the environmental performance through CASBEE was that Water Housing exhibited a high environmental performance when both the environmental load and quality were included. Water Housing is more comfortable than a local house above the land and it offers effective evaporative cooling as a result of using water and provides proper ventilation. The assessment introduced here demonstrates both the environmental performance of vernacular architectures from multiple perspectives and the efficiency of CASBEE as an environmental performance visualization tool.

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.

Maintaining good quality of life among elderly residents of nursing homes is becoming more important as their numbers increase with the ageing of society. Dry mouth, or xerostomia, is one condition that must be prevented, as it can lead to various serious diseases. However, older people are susceptible to dry mouth due to reduced lip closing force. In this study, a field survey of the indoor environment of nursing homes and oral dryness among nursing home residents was conducted in winter 2015. Twenty-seven facilities were classified as dry or moist based on measured indoor humidity. Ordered logistic regression analysis showed that the likelihood of dry mouth was significantly lower among patients residing in the moist group compared with the dry group.

The decline in physical fitness among elementary school students has become a social problem, and there is a need to promote physical activity in these students. The promotion of physical activity also has an impact on health and learning. In this study, we examined the effects of the elementary school facility environment on the physical activity of students, using a questionnaire survey and actual measurements of physical activity. The analysis results suggested that students at elementary schools having a good schoolyard environment walked more and that the operation of the school affects student’s school-time step counts.

Physical activity contributes to a variety of health benefits. Therefore, preventing sedentary behavior is critical for the promotion of physical activity in people of all ages. This study was to clarify the relationship between sedentary behavior and the living environment. This study surveyed residents living in houses with adequate insulation performance. In the cross-sectional survey, we examined the relationship between living environment and sedentary behavior at the daily and individual levels, using multilevel analysis. In the intervention survey, we examined the relationship between changes in the indoor thermal environment and sedentary behavior by requesting the active use of heating.

A field survey using actual indoor temperature measurements and questionnaires was conducted in Yusuhara, Kochi Prefecture, in November 2019. Based on the field survey, ordinal logistic regression analysis was conducted to identify common characteristics of residents living in a cold environment at waking and before bedtime. Low insulation performance, the type of heating equipment used such as electric heater and air conditioners, and personal attributes such as age, number of people in the household and length of time at home were significant risk factors for living in cold houses.

 In Japan, a unified system to measure environmental loads in administrative areas has not been officially established for environmental accounting at the local government level. As a consequence, environmental accounting has not been adopted by local governments as widely as private companies. Life cycle impact assessment (LCIA) is one aspect of research in the field of life-cycle assessment, whereby environmental loads throughout the life cycle of products and services are measured in a quantitative way. Research in which environmental loads are determined according to geographic location has become more and more important. This study therefore focused on Japanese minimum administrative divisions (municipalities) and attempted to quantify the annual environmental loads emitted within each division in the year 2015 using the LCIA method. For this, this study leveraged the assessment theory Life-Cycle Impact Assessment Method Based on Endpoint Modeling 2 (LIME2). This method is able to calculate assessment results in monetary units called the "Eco-index Yen" (unit: Japanese yen) while integrating the environmental loads of several impact categories, such as "Global warming" and "Land use", based on environmental conditions and knowledge unique to Japan. Using statistical information that was reliable, verifiable, and comparable, the environmental damage amount for the whole of Japan was calculated to be 8.53 trillion yen. The top five amounts were "Global warming" (2.82 trillion yen), "Land use" (2.33 trillion yen), "Waste (domestic)" (1.24 trillion yen), "Biological toxicity" (0.63 trillion yen), and "Atmospheric pollution" (0.61 trillion yen). When the damage amounts were divided by the population of each municipality, the average amount per capita for all Japanese municipalities was calculated to be 67,100 yen per capita (population-weighted average). These damage amounts per capita were placed on a map of Japan according to type of impact category and type of business to visualize the regionality of environmental loads nationwide. The values for "Global warming" and "Land use" tended to be lower in the central parts of large urban areas, and the values for "Global warming" and "Atmospheric pollution" tended to be higher in areas where industries are concentrated. The values for "Primary industries" (which include agriculture) as well as "Manufacturing" were particularly indicative of local industrial activity. Tendencies related to population distribution and industrial activity were easy to see from the map. Next, standard deviation and variation coefficient for the damage amounts per capita were calculated for each region in order to statistically capture the disparities of environmental loads according to impact category and type of business. The disparities of environmental loads that were deeply related to housing, such as "Waste (domestic)" and "Land use", tended to be narrow among municipalities whereas disparities for "Manufacturing" were particularly wide because manufacturers are concentrated in certain parts of the country. From these results, this study revealed Japanese environmental impacts from the perspective of several categories, thus providing information useful for making decisions about environmental policies.

 In Japan, a unified system for measuring environmental loads in administrative areas has not been officially established. In a previous study, the authors focused on Japanese minimum administrative divisions (municipalities) and quantified the annual environmental loads attributable to each division in the year 2015 using the LCIA method. For this, the study leveraged the assessment theory of the Life-Cycle Impact Assessment Method Based on Endpoint Modeling 2 (LIME2). This method is able to calculate assessment results in monetary units via the so-called "Eco-index Yen" (unit: Japanese yen) while integrating the environmental loads of several impact categories, such as "Climate change" and "Land use". Based on this, the present study sought to conduct the same assessment for each year from 2000 to 2015, and visualize the temporal changes in environmental loads within all Japanese municipalities by impact categories and by type of business. Using statistical information that was reliable, verifiable, and comparable, the total environmental damage amount for the whole of Japan was calculated to be 8.40, 8.47, 7.50, and 7.41 trillion yen in 2000, 2005, 2010, and 2015, respectively. This indicates that damage amounts were generally on a downward trend throughout the 16-year period. Focusing on impact categories, the damage amounts for five categories, "Photochemical ozone, " "Resources consumption, " "Acidification, " "Atmosphere pollution, " and "Waste (domestic), " decreased every five-year period. Focusing on the type of business, the damage amounts for "Primary Industries (Agriculture, etc.)" and "Secondary Industries (Manufacturing, etc.)" decreased every five-year period, and the damage amount for "Tertiary Industries (Service industry, etc.)" began to decline in 2005. This suggests that damage amounts reflect the effects of environmental policies and the activities of industries over time around the country. Next, the temporal changes in damage amounts were placed on a map of Japan to visualize patterns across municipalities. In overall terms, declining damage was discerned across many municipalities between 2005 and 2010. This tendency was particularly pronounced in the "Climate change" and "Atmosphere pollution" impact categories and the "Construction" and "Manufacturing" industries. This likely reflects not only local environmental policy interventions, but also the global financial crisis that began in 2008. From these results, it became possible to visualize the change over time in environmental loads based on social factors related to each period in Japan. This study provides information that can be used for making decisions about environmental policies, as well as primary knowledge needed to develop standardized environmental accounting guidelines for Japanese municipalities.

Solar energy would be the most important energy resource. The highest performance solar-energy receiver recorded utilizing 74.3 % of the solar energy in total of electricity and 40 °C hot water in summer, Yokohama, Japan, has already been reported in 2020 as a photovoltaic/Thermal (PV/T) solar panel. In this paper, the system design on introducing the PV/T solar panel to be a part of energy-supply system in a household and the simulation results are reported. Using a Monte Carlo simulation method, it can generate different energy demands at every 15 minutes through a year for various family members as the simulation calculation, while the results always follow the input existing statistics information. Not only solar-energy management in a household but also the environmental thermal load is evaluated. An example of the net-zero energy house having the best combination of the environmentally friendly PV/T and PV solar panels is presented in this paper.

A questionnaire survey was administered to adult residents of three locales: a large city (Kitakyushu city) a small city (ObuseTown) and a rural village (Yusuhara town), in order to clarify the hierarchical structure of health related factors of housing and regional environment dependent on urban structure and scale. As a result of structural equation modeling, health related factorsmodel in Yusuhara was shown that 35% of residents' overall health may depend on their housing and regional environment, and it was the largest percentage of three locales. Besides, differences were found among the health related factors structure. These results indicate that design guidelines for health promotion that correspond to the urban structure and scale will be required.

In recent years, not only the residence but also the effort of health promotion by improving the social environment including the working and the regional environment has attracted attention. This paper introduces a subjective assessment tool of the work environment, referred to as "CASBEE- Office Health Checklist". This tool is an assessment tool for workers themselves to evaluate satisfaction for office environment where workers spend a lot of time. By using this tool, people are aware of factors that affect health and intellectual productivity, and it is expected that they can conduct health management strategically, which leads to environmental improvement.

 A global standard method for measuring environmental loads in administrative divisions has not been officially established for environmental accounting at the local government level. As a consequence, environmental accounting has not been adopted by local governments as widely as private companies around the world. Life cycle impact assessment (LCIA) is one aspect of research in the field of life-cycle assessment, whereby environmental loads throughout the life cycle of products and services are measured in a quantitative way. Research in which environmental loads are determined according to geographical location has become more and more important. This study therefore focused on administrative divisions in 42 countries, most of which are OECD members, and attempted to quantify the annual environmental loads emitted within each division in the year 2015, using the global-scale LCIA method. For this, this study leveraged the assessment theory Life-Cycle Impact Assessment Method Based on Endpoint Modeling 3 (LIME3). This method is able to calculate assessment results in monetary units while integrating the environmental loads of several impact categories, such as climate change and land use, based on environmental conditions and environmental science. Using statistical information that was reliable, verifiable, and comparable, this study calculated environmental loads in administrative divisions in 42 countries. The total environmental damage amount for the 42 countries was calculated to be 5.22 trillion USD. The top five amounts were land use (1.76 trillion USD), water consumption (1.36 trillion USD), forest resource consumption (0.70 trillion USD), climate change (0.52 trillion USD), and fossil fuel consumption (0.50 trillion USD). When the damage amounts were divided by the area or population of each division, the average amount per unit area for all Territorial level 2 (TL2) regions was calculated to be 67,300 USD/km2 (area-weighted average), and the average of amount per capita was calculated 1,250 USD/capita (population-weighted average). These damage amounts per unit area and per capita were placed on a world map according to impact category to visualize the regionality of environmental loads worldwide. The amount per unit area for most categories showed a trend similar to population distribution around the world, and the values for land use also showed a trend indicative of local agricultural activity in some countries. In particular, the amount per capita for climate change as well as the total of all categories showed a contrasting trend to the amount per unit area, and the value tended to be relatively lower in densely populated areas around the world. The variation coefficient for the damage amounts per unit area and per capita was calculated for each region in order to statistically capture the disparities of environmental loads according to impact category. The disparities of environmental loads that were deeply related to housing, such as climate change and waste, tended to be narrow among TL2 regions worldwide. From these results, this study revealed environmental impacts around the world from the perspective of several categories, thus providing information useful for making decisions about international environmental policies.

 Given the rapid ageing of the Japanese population, it is important to identify strategies to minimise the gap between healthy life expectancy and average life span. Cold-related injuries and symptoms have recently attracted attention, and studies on the relationship between blood pressure, falls, physical performance, and the thermal environment of housing have been reported. Based on previous studies, we hypothesised that people living in cold homes will receive certification for long-term care insurance earlier in life, indicating a shorter healthy life expectancy. This retrospective study involved 205 community-dwelling older adults living in Japan. Participants completed a self-report questionnaire about personal characteristics, housing, and perceived indoor temperature in their home during winter. Participants were divided into a Cold group and a Warm group based on perceived indoor temperature. Mean and minimum living room and bedroom temperatures differed between the Cold group and Warm group. On the other hand, mean, maximum, and minimum temperatures in the dressing room all differed significantly between the Cold group and the Warm group. Air conditioners were the only heating system that contributed to warmer indoor temperature. Maximum temperature was higher but minimum temperature was lower in houses with fan heaters, which may run intermittently and with short running time. Houses in which kotatsu systems or electric blankets were used tended to have colder indoor temperatures in the living room and bedroom. The Kaplan-Meier method was used to analyse the relationship between age at certification for needing long-term care insurance and perceived indoor temperature. Mean age at certification was 77.8 years in the Cold group and 80.6 years in the Warm group (p<0.01, generalised Wilcoxon test). Multivariate analysis by ANCOVA revealed a significant main effect of perceived indoor temperature, with the Cold group having a younger age at certification for needing long-term care (F(1, 197)=9.27, p<0.01). Estimated marginal means indicated that healthy life expectancy was 2.9 years shorter in the Cold group than in the Warm group even after adjusting for participant characteristics. When the relationship between measured indoor temperature and age at certification was tested, people living in houses with low indoor temperature (<14 °C) or high indoor temperature (≥18 °C) had a higher age at long-term care certification. People with low indoor temperature might spend longer time outside and use heating systems for shorter time. Since we could not grasp or control times going-out or using heating system, we conclude that relationship between measured indoor temperature and age at certification can support the previous result though, close investigations of indoor thermal environment in where older people lives are still needed. Our findings suggest that maintaining an appropriate indoor thermal environment could help prevent the need for long-term care.

 The severe damage caused by the Great East Japan Earthquake in 2011 highlighted the shortcomings in disaster reduction. Therefore, the concept of resilience has drawn much attention to reduce damage and to achieve restoration of services in addition to preventing damage; thus, new policy guidelines in various fields have been published.  To improve residence resiliency, it is important not only to prepare for physical needs, but to understand the risks during disasters, to take appropriate action, and to make homes safe to avoid injuries and accidents in everyday life. However, the actual extent to which residents have made these preparations is not properly understood. Factors affecting residence resiliency is unclear, and it is necessary to clarify this and to consider measures to promote resident preparation.  In this research, we conducted a questionnaire survey on residents’ disaster preparation and awareness to evaluate residence resiliency and analyze the factors affecting residence resiliency. The questionnaire survey results show that the higher the household income and the higher the age of the resident, the higher the residence resiliency. Residents living in areas affected by the Great East Japan Earthquake showed a relatively high resilience. In addition, factor analysis was conducted, and we extracted elements describing residence resiliency. Eight factors were extracted from questionnaires on resilience, and the factors were classified as “Risk understand 1”, “Risk understand 2”, “Life continuity”, “Action plan”, “Links with region”, “Equipment preparation”, “Daily safety”, and “Information”. Evaluating the resilience for each factor indicated that the “Links with region” and “Equipment preparation” factors are inadequate, and that information is provided according to these factors.  We analyzed the relationship between residents' awareness and residence resiliency by structural equation modeling. The results showed that concerns about primary damage and mutual help awareness affect disaster prevention awareness, and that disaster prevention awareness affects residence resiliency. Therefore, to improve residence resiliency, activities to improve mutual help awareness should be promoted and residents should be encouraged to recognize the risk of disaster and the possibility of damage. However, in the model we created, disaster prevention awareness only accounts for 26% of residence resiliency, and the effect of household income and age is large. Therefore, measures for promoting preparation among those with low income and among young people are important.

The first purpose of this study is to simulate the emission of life cycle greenhouse gas (GHG) including fluorocarbon leakage from thermal insulation of houses and comprehensively evaluate both the reduction of C0_2 emission by heating and cooling and the rise of GHG emission by fluorocarbon leakage. The results of the simulation are as follows; 1) Life cycle CO_2 emission by heating and cooling of 1999 standard is reduced by 50% than that of 1980 standard. 2) However, GHG emission including fluorocarbon leakage rises in some cases. The second purpose of this study is to forecast GHG emission by heating and cooling, manufacture of building materials and fluorocarbon leakage from all houses in Japan up to 2012. The results are as follows; 3) If the current situation continues, CO_2 emission by heating and cooling for the period 2008-2012 will rise by 9.9% compared to 1990 levels. 4) If thermal insulation of new housing is improved as rapidly as possible by 2010, it will rise by 9.1%, but however, GHG emission including fluorocarbon leakage will rise by 18.7%. 5) On the other hand, if measures for fluorocarbon leakage are taken, it could be reduced by 0.6%. 6) In addition to these measures, if thermal insulation of existing residential buildings is implemented, it could be reduced by 3.1%.

 Increasing the workplace productivity of workers has great economic value and is essential for achieving a sustainable society and economic progress. One way to increase workplace productivity is to improve the work environment, which is important because of its strong influence on workers. The work environment can be improved by using air conditioning to change the thermal environment. In Japan, radiant air-conditioning has received attention as a means to realize energy-saving buildings. However, the difference between the effects of radiant air-conditioning vs. convective air-conditioning on the human body is not clear. Therefore, in this study, we examined these effects on the physiology, psychology, and workplace productivity of workers. In February 2019, we conducted a 5-day experiment with 24 university students (12 males, 12 females). Rooms simulating office conditions were equipped with either a radiant or convection unified air-conditioning system (unified SET*, 27.2°C). In the rooms, the students simulated work such as typing, performing calculations, and creating mind maps between 9:00 and 17:00, changing rooms each day. Physiological measurements such as skin temperature were taken to evaluate stress levels, and a questionnaire was completed by the students to determine perceived comfort. Workplace productivity was evaluated based on the results of the simulated work and questionnaires. The following findings were obtained by this experiment. 1. The skin temperature difference between hands and face (hand-face) was significantly greater in convection air conditioning than in radiant air conditioning for both male and female. It was confirmed that the decrease in the skin surface temperature of the hand with respect to the face had a correlation with psychological quantities such as a decrease in thermal environment satisfaction, a decrease in air flow comfort, and an increase in subjective symptoms. 2. Thermal environment satisfaction was significantly improved in male during convection air conditioning and in female during radiant air conditioning. 3. Thermal environment satisfaction had the strongest correlation with airflow velocity. Focusing on the correlation between thermal environment satisfaction and air velocity during convection air conditioning, positive correlations were found for male and negative correlations for female, confirming different trends for male and female. 4. Focusing on airflow speed and airflow comfort, male tended to improve airflow comfort slightly when airflow speed was high, whereas female showed a marked decrease in airflow comfort when airflow speed was high. The preference for airflow was different between male and female. 5. The more comfortable the air flow was, the less fatigue was felt. 6. For female, comparing radiant air conditioning with convection air conditioning, convection air conditioning increased the rate of "yawning" subjective symptoms by 17.6% and "sleeping" by 8.3%. Other complaints regarding fatigue were also increasing, and it is considered that the unpleasant airflow led to drowsiness and fatigue. 7. Regarding work performance, we performed a multi-level logistic regression analysis with fatigue as an explanatory variable. The ratio of work scores "individual deviation value of 50 or more" is 2.0 to 2.9 times significantly higher when not feeling fatigued than when feeling fatigued in calculation, typing, mind map and all simulated work.

In the building field, for the purpose of further energy saving and lower carbon intensity, area-wide energy utilization is expected to play an important role in Japan. But such projects require agreement among stakeholders belonging to the area, which is one of the major hurdles of the realization. This paper describes the promotion measures to motivate agreement among stakeholders as below; 1. Indicating the further improvement of the cost-benefit ratio (B/C) to be shared among stakeholders in consideration of a variety of non-energy benefit (NEB) 2. Identifying B/C for each stakeholder in consideration of the revert of each cost and benefit belonging to some specific stakeholders 3. Expression of the risk caused by the uncertainty of cost and benefit estimation in the early planning phases of projects, and seeking proper allocation of cost and benefit, depending on the difference of the risk preference among stakeholders The effectiveness of the concept above is verified through a case study based on an actual project.

The United Nations' (UN) sustainable development goals (SDGs), the core of the 2030 Agenda for Sustainable Development and the UN Paris Agreement, were adopted in 2015. Involvement of not only national governments but also all other stakeholders including local governments is important to promote sustainable development and to achieve the goals. The question arises, therefore, of what methods should be used to best implement and assess sustainability issues at a local level. In this light, a new version of Comprehensive Assessment System for Built Environment Efficiency (CASBEE), CASBEE for Cities, is introduced for assessing the sustainability of cities and communities around the world based on SDG indicators and greenhouse gas (GHG) emissions. The tool allows users to understand the sustainability of cities and communities based on quality (Q) and environmental load (L) perspectives. The sustainability assessments show that cities in developed countries tend to have good grades for Q, but bad grades for L, while cities in developing countries tend to have the opposite trend. This will assist cities and communities in both developed and developing countries to understand urgent problems and to identify effective solutions for sustainable development.

Community-level decentralized and self-reliant energy network is expected to contribute to create a sustainable community as well as its self-vitalization and energy resiliency. But implementation of this system requires consensus among variety of stakeholders and long payback period, which are major hurdles. This study proposes the following concept and methods; (1)PPP business scheme consisting of two types of actors; "community-level energy network infrastructure operating company" and "on-site energy production and service providers". (2)Proper re-allocation of cost and co-benefits among stakeholders by taking advantage of opportunities of adjusting tariffs, taxes, subsidies for the purpose of equalizing each stakeholder's B/C.