論文

The study analyzes the thermal environment and energy-saving performance of nearly net-zero energy apartments in Japan during winter by measurement and questionnaire. Results show the average indoor temperatures exceeded 18°C even without air conditioning, due to superior insulation performance. Energy consumption for heating was 58.9% to 62.9% of the national average, and residents perceived their homes as warmer, leading to lower temperature settings of air-conditioner. However, there were several challenges, such as the low ratings by residents of non-heated rooms during winter.

Worker performance is affected by environmental stimuli in the office. Therefore, it is important to analyze the relationship between workers and multiple environment elements simultaneously in order to understand the relationship between the office environment and worker performance. In addition, surveying a large sample of offices simultaneously is desirable to obtain more practical insights. Therefore, this study surveyed multiple elements of the physical office environment related to worker performance in a large sample of offices. The elements of the physical office environment surveyed were air temperature, relative humidity, CO2 concentration, and sound pressure level during the summer. Along with measurements from 58 offices across 29 buildings in Tokyo, Japan, 947 responses to a questionnaire survey of workers conducted to evaluate work performance were analyzed to elucidate the relationship between these elements of the physical office environment and perceived work efficiency. The analysis showed that air temperature was more related to worker performance than to the other elements. In addition, 25 °C air temperature group was observed to be associated with high worker performance, with worker performance being lowest in the 27 °C group. This finding is expected to provide insight into indoor environments that can effectively enhance office worker performance.

Well-being is a positive mental state that includes evaluations and affective reactions individuals make about their experiences, including life evaluation, affect, and eudaimonia. The importance of well-being is underscored by its association with productivity, health, and longevity. Despite extensive research on well-being related to demographics, personality traits, and satisfaction in various life domains, it remains unclear how and to what extent the office environment impacts workers' well-being. Therefore, this study explores the impact of the office environment on workers' subjective well-being, using structural equation modeling. Conducted with 1438 white-collar workers working in 61 offices in Tokyo, Japan, the survey assessed perceived office environment and measured subjective well-being based on guidelines from the OECD. The key findings indicate a significant association of the office environment with life domain factors such as satisfaction with one's job, work–life balance, private life, and subjective health, which are positively correlated with overall subjective well-being. In particular, common-area environments within the office such as spaces that promote refreshment and conversation have the most significant impact on well-being. The analysis model also revealed that the perceived quality of the office environment had a positive correlation with subjective well-being even after adjusting for demographic information such as age, gender, and personality traits. This research provides valuable insights for improving the design of office environments to foster workers' well-being.

The residential environment impacts the health and economic status of residents, for example, via medical costs and income loss from absenteeism. However, previous studies often do not consider assessments of the thermal, acoustic, light, hygiene, safety, and security environments in the residence simultaneously, and the age and sex of the residents. Therefore, this study proposed improvements to a previous method and validated the improved method for estimating health economic impact that considers the residential environment conditions and residents comprehensively. The individual scale validation demonstrated that the relationship between the comprehensive assessment of the residential environment and the risk of 10 types of diseases (diabetes mellitus, cerebrovascular diseases, disorders of conjunctiva, hypertensive diseases, heart diseases, upper respiratory tract disorders, chronic obstructive pulmonary disease, asthma, dermatitis and eczema, and inflammatory arthropathies) differs by age and sex. When these disease-related economic losses were aggregated, older males were estimated to suffer the greatest losses from their residential environment in Japan. The economic impact of residential environment by resident attributes was aggregated according to the population distribution as an advanced application of the estimation model. The total economic loss from substandard residential environments across Japan was estimated to be about JPY 725 billion per year. These results should incentivize residents and policymakers to improve the residential environment. The estimation-model development process is universally applicable and may lead to the creation of optimized benchmarks in every region of the world, thereby contributing to improvements in the residential environment aimed at reducing health risks and economic losses.

Based on numerous cross-sectional analyses, the residential environment has been identified to have an impact on residents’ health status. However, there has been little study of whether these impacts persist in the long term or diminish over time. Accordingly, the present study used data tracking of more than 15,000 residents for nearly 10 years to examine the long-term relationships between the residential environment and residents’ health status using the Kaplan–Meier method and discrete time logit models. The results revealed that higher comprehensive assessment of the thermal, acoustic, light, hygiene, safety, and security environment in the residence is likely to extend the period until health deteriorates. Specifically, the period until low subjective health perception was about 2 years longer for residents in the top 16% of assessments of the residential environment compared with the national average assessment. This trend was also supported by supplementary analyses using the incidence of 10 types of non-communicable diseases: diabetes mellitus, cerebrovascular diseases, disorders of conjunctiva, hypertensive diseases, heart diseases, upper respiratory tract disorders, chronic obstructive pulmonary disease, asthma, dermatitis and eczema, and inflammatory arthropathies. These findings are relevant for a wide range of stakeholders, from individual residents to policymakers, and highlight that a good residential environment effectively promotes healthy longevity. This study will serve as a starting point for further long-term studies.

高断熱集合住宅における床チャンバー方式の全館空調が、住宅内温熱環境と夏季の睡眠及び冬季の血圧に及ぼす影響の検証を行った。調査は高断熱かつ床チャンバー方式の全館空調を採用した集合住宅への、転居前後(2022・2023 年度)の夏季及び冬季に行った。転居後では断熱性能及び床チャンバー方式の全館空調の効果により、各室の室温は夏季・冬季ともに改善・安定化した。また、居間の上下温度差は夏季に拡大したが、冬季に縮小した。加えて、居間・寝室の相対湿度は夏季・冬季ともに低下し、寝室のCO2濃度は改善した。その結果、夏季の睡眠効率及び冬季の血圧に関しても、改善・安定化する可能性が示唆された。

Despite the recognition of housing as a determinant of health, most prior studies relied on cross-sectional data, limiting their ability to infer causal effects of residential environments on residents’ health. This study addresses these gaps by conducting a two-wave, 7-year prospective cohort survey, utilizing a cross-lagged panel model, a method also used in public health research, to rigorously analyse causal paths from residential environment quality to health status. Data were collected from 2153 residents on personal attributes, residential environments, and the presence of physician-diagnosed disease among 10 major non-communicable diseases. The analysis identified significant causal effects of residential environment quality on the onset of hypertension, heart disease, and asthma. Odds ratios indicated that better residential environments significantly reduced the likelihood of developing these conditions, particularly hypertension (0.791), heart disease (0.554), and asthma (0.593). Given the high proportion of time people spend indoors, these results underscore the importance of residential design. However, for other diseases where significant causality could not be confirmed in this study, the prevalence samples or the survey intervals may have influenced the results. Addressing these challenges could potentially expand insights, and it is premature to conclude that there is no causal relationship for the remaining diseases. In conclusion, this study expands knowledge in the field of housing and health and highlights the importance of the residential environment in influencing individual health status.

The quality of the office environment has a substantial impact on workers’ comfort, health, and productivity. Assessing these environments and identifying key elements that influence occupant satisfaction is the starting point for designing better offices. This study uses item response theory (IRT) to analyze post-occupancy evaluation (POE) data and identify key elements of the office environment. The use of POE to analyze the built environment has been limited, making this study an innovative approach. A survey of 3552 workers was conducted to subjectively evaluate various office elements in addition to personal attributes, and data-driven methods were used to identify key office environment items. The results show that the factors with the greatest effect on the occupants’ assessment of the overall office environment include comfortable interiors and furnishings in individual workspaces. Spaces that encourage conversation were the next most important, with many of the most important items related to the common-area environment in the building. The analysis also reveals differences based on gender and occupation, with women valuing aspects of the building operation and maintenance environment more than men do, and clerical workers valuing the common-area environment more than technical workers do. The study underscores the need for an office space design that considers the varying needs of the personal attributes of different workers.

本研究では、生産施設の空調設備における省エネルギー化を目的として、画像センサと機械学習を活用した最適制御技術を開発し、その検証を行った。画像センサによる在室人数の検知を基にした VAV 風量制御により、外調機ファンの消費電力を最大41％削減できた。さらに、機械学習を活用した空気熱源モジュールチラーの冷水送水温度の最適化により、システムCOP を0.51 から0.67 に向上させた。また、これらの省エネルギー効果を達成しながら、生産エリアの温湿度への影響を最小限に抑えることを実証した。本研究は、生産施設全体のエネルギー消費を効率化するための、画像センサや機械学習を活用した自動最適制御の有用性を明らかにするものである。

本研究は、生産施設における新たなエネルギー評価基準として、ZEF（net Zero Energy Factory）を提案し、その適用事例を報告するものである。ZEFは、生産エリアの空調、換気、照明を含む包括的な評価を可能にする、従来のBELS認証によるZEB評価の課題を補完する評価基準である。このコンセプトを取り入れ設計した工場では、BELS認証によるZEBの基準値313MJ/m2に対して、ZEFの基準値は約4.4倍の1,389MJ/m2となった。また、運用実績データから、Nearly ZEF（BEI=0.06）を達成する性能が確認された。本研究は、ZEFが生産施設全体のエネルギー消費量を可視化し生産施設間の比較を可能にする、普遍的な評価基準としての有用性を示すものである。

The rapid adoption of remote working has increased the importance of indoor environmental quality (IEQ) in residential environments. However, the relationship between residential environments and remote working productivity remains under discussion. Exposure to cold indoor environments during winter may contribute to decreased productivity because discomfort and thermal stress can impair cognitive performance. Many previous studies have examined the direct relationship between IEQ and productivity in thermal comfort research, overlooking the stepwise influence of physiological and psychological responses. However, IEQ probably affects productivity through the physiological and psychological responses of workers. Therefore, this study examines the effects of residential floor-level thermal environment on task performance through psychophysiological responses using multilevel SEM. A controlled experiment was conducted with participants performing work tasks in either a convective air-conditioned room or a radiant floor-heated room. Physiological (foot skin temperature), psychological (thermal comfort and concentration), and task performance measures were collected and analyzed. Multilevel SEM revealed that radiant floor heating significantly increases foot skin temperature, which improves thermal comfort and perceived concentration. In addition, no differences were observed among conditions for simple tasks, such as typing, whereas improved physiological and psychological states positively affected performance on cognitively demanding creative tasks. The results underscore the critical role of floor-level thermal environments in supporting work-from-home productivity. By integrating multilevel SEM, this study advances the understanding of hierarchical human–environment interactions. The results suggest that incorporating radiant floor heating into residential design can improve both comfort and cognitive performance, contributing to home workspaces that are more comfortable and productive.

High sleep quality is essential for people’s health. Numerous studies have investigated the relationship between indoor environmental quality and sleep quality, and the thermal environment, in particular, has been shown to have a significant effect on sleep quality. However, most of these studies measured the thermal environment of the bedroom for only short periods of time. Although seasonal variations and individual differences in sleep quality have been reported, most studies on the thermal environment and sleep quality have not adequately taken these factors into account. Therefore, the present study measured bedroom temperature and sleep quality objectively without intervention for 1 year and mathematically modeled the annual variation in bedroom temperature and sleep efficiency using a simplified sine function. This mathematical model was able to quantitatively characterize individual differences in the annual variation of bedroom temperature and sleep efficiency. The amplitude and phase of the sine function indicate the annual variation range of sleep efficiency and the degree to which sleep efficiency decreases in summer or winter. The mathematical model was also able to identify bedroom temperatures that optimize sleep efficiency. Analysis of each participant’s annual bedroom temperature and sleep efficiency revealed that sleep efficiency was high in the spring and fall when temperatures were moderate for all participants, while sleep efficiency decreased during the summer and winter and that there were individual differences in terms of whether sleep efficiency decreased more during the summer or winter. Furthermore, there were differences in the bedroom temperature that optimized sleep efficiency for each individual, and the vulnerability of sleep efficiency to fluctuations in bedroom temperature also differed for each individual. By utilizing the developed mathematical model, the bedroom temperature could be individually controlled to enhance sleep efficiency, thereby impacting health and performance.

Indoor environments play an important role in children’s health and behavior, yet the impact of thermal environments on physical activity remains insufficiently understood. This study investigated the association between indoor thermal environments and children’s physical activity in summer and winter in Japan. Detailed indoor thermal measurements and objective accelerometer data were collected from 26 children aged 4–12 years, each measured in both seasons under parental supervision to ensure data quality. Significant associations were found between temperatures in living areas and physical activity intensity. Warmer indoor environments in winter were associated with higher activity intensity, whereas cooler indoor environments in summer were associated with lower activity intensity. A new indicator, the seasonal activity ratio (SAR), defined as the ratio of winter to summer activity intensity, was developed to assess the degree of seasonal variation. The SAR showed an overall seasonal decline (mean SAR: 0.96 ± 0.06). Children living in homes where non-living areas maintained cooler environments in summer and warmer environments in winter exhibited significantly smaller seasonal declines in activity compared with those in other environments. These findings demonstrate that even in modern, high-performance homes, a thermal design strategy is required that addresses both living and non-living areas in order to promote children’s physical activity year-round and to mitigate typical winter declines. The results of this study provide objective evidence to inform residential design and policies aimed at fostering healthier indoor environmental quality for children.

This study developed a model for estimating energy consumption and CO2 emissions up to 2050 in the household sector in Japan. The total national energy consumption of the BAU case would be 1,136 PJ, a 53.4 % reduction compared to 2013. The total national CO2 emissions would be 10.18 Mt-CO2, a 94.1 % reduction compared to 2013. In addition, energy consumption and CO2 emissions will not reach zero even if Japan achieves current policy targets, suggesting that further efforts will be needed to reduce CO2 emissions to zero.

The purpose of this study was to estimate healthy life expectancy at the small-area level and to examine the association between neighborhood environments and healthy life expectancy, both directly and indirectly through social capital (SC), using community facility indicators as proxy measures of SC. Multiple regression and path analyses were conducted to explore the relationships among neighborhood environment, proxy SC indicators, and healthy life expectancy. The results suggested that neighborhood environment was indirectly associated with healthy life expectancy through SC, with differences observed by age group and gender.

Hybrid work has been widely adopted, but thermal comfort in home workspaces has received less attention than that in laboratories and offices. The adaptability of home workspaces may be associated with individual differences, including those related to personality traits. Thus, the analysis focused on two issues: (i) the relationships among temperature, humidity, and thermal sensation at home, and what neutral temperatures arise in summer and winter; and (ii) how these relationships vary with personality traits. A field survey was conducted in the Tokyo metropolitan area. In situ physical measurements of indoor air temperature and relative humidity were obtained simultaneously in 60 homes in summer and 190 in winter, and these measurements were paired with concurrent occupant evaluations while working from home. Ordinal logistic regression estimated neutral temperatures of 28.1 °C in summer and 21.0 °C in winter, which is a wider seasonal gap than is commonly reported for offices. The associations between personality traits and neutral temperature differed by season. In summer, higher levels of extraversion and neuroticism were associated with a higher neutral temperature. For neuroticism, shifting from −1 to +1 standard deviation moved the neutral temperature from 27.4 to 28.8 °C (Δ 1.4 °C). In winter, the neutral temperature increased with extraversion and decreased with openness. These results highlight season- and personality-related variation in estimated neutral temperatures and provide empirical benchmarks for thermal comfort in home workspaces.