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The global demand for air conditioners (ACs) has more than tripled since 1990, with 1.6 billion units currently in use. With the rapid economic and population growth of countries located in the hottest parts in the world, this trend is likely to continue in the future. The aim of this study was to show the benefits of introducing air conditioners with different materials or different technologies such as inverters with high energy-saving performance on the environment and human health in Indonesia. To evaluate the environmental impacts of the different technologies, a cradle-to-grave life cycle assessment (LCA) of air conditioners was conducted using the life-cycle impact assessment method based on endpoint modeling (LIME3). As expected, the use stage has the largest global warming potential (GWP), representing more than 90% of the impact, whereas copper and nickel have the most important impact in terms of resource consumption (about 50%). We found that the impacts are heavily dependent on the country’s energy mix, but reduction can be achieved by introducing better technologies. The integration factors from LIME3 were then applied to estimate the external cost of each model; the results showed that the use stage also has the most influence. Even though the impact of climate change is important, air pollution impact must be seriously considered as its impact was found to be the highest (about 60% of the total impact). The external cost was finally compared to the possible benefits produced by the introduction of air conditioning technologies during their 10-year life cycle. We found that the impacts are twice that of the benefit for the best model (USD 2003 vs. 1064); however, the novelty of this study is that the benefit was also considered. In the future, developing countries should promote AC models with inverters, refrigerants with low global warming impact such as natural refrigerants, and encourage the recycling of units as soon as possible. The energy mix for electricity production is also a key parameter to consider.
Selim Karkour; Tomohiko Ihara; Tadahiro Kuwayama; Kazuki Yamaguchi; Norihiro Itsubo. Life Cycle Assessment of Residential Air Conditioners Considering the Benefits of Their Use: A Case Study in Indonesia. Energies 2021, 14, 447 .
AMA StyleSelim Karkour, Tomohiko Ihara, Tadahiro Kuwayama, Kazuki Yamaguchi, Norihiro Itsubo. Life Cycle Assessment of Residential Air Conditioners Considering the Benefits of Their Use: A Case Study in Indonesia. Energies. 2021; 14 (2):447.
Chicago/Turabian StyleSelim Karkour; Tomohiko Ihara; Tadahiro Kuwayama; Kazuki Yamaguchi; Norihiro Itsubo. 2021. "Life Cycle Assessment of Residential Air Conditioners Considering the Benefits of Their Use: A Case Study in Indonesia." Energies 14, no. 2: 447.
We conducted a detailed estimation of direct and indirect CO2 emissions related to multi-person households in 49 Japanese cities. Direct energy consumption was decomposed into energy use in order to consider the relationship with regional conditions. The results showed that CO2 emissions from direct energy consumption were almost as large as indirect CO2 emissions induced by consuming products and services, suggesting that lifestyle improvements are important for both energy savings and reducing CO2 emissions relating to product and service consumption. In addition, CO2 emissions from direct energy consumption varied widely between cities, making them susceptible to regional conditions. We also calculated CO2 emissions from direct energy consumption and examined the regional conditions for individual forms of energy use. CO2 emissions were higher in cold regions and lower in larger cities. In Japan, large cities are often located in relatively warm areas, so we conducted an analysis to distinguish the effects of climatic conditions from those of urbanization. This analysis allowed us to clarify the effects of regional conditions on factors such as heating/cooling and the ratio of detached houses to apartments.
Yujiro Hirano; Tomohiko Ihara; Masayuki Hara; Keita Honjo. Estimation of Direct and Indirect Household CO2 Emissions in 49 Japanese Cities with Consideration of Regional Conditions. Sustainability 2020, 12, 4678 .
AMA StyleYujiro Hirano, Tomohiko Ihara, Masayuki Hara, Keita Honjo. Estimation of Direct and Indirect Household CO2 Emissions in 49 Japanese Cities with Consideration of Regional Conditions. Sustainability. 2020; 12 (11):4678.
Chicago/Turabian StyleYujiro Hirano; Tomohiko Ihara; Masayuki Hara; Keita Honjo. 2020. "Estimation of Direct and Indirect Household CO2 Emissions in 49 Japanese Cities with Consideration of Regional Conditions." Sustainability 12, no. 11: 4678.
This study focused on the effects of green roofs in office building districts. The purpose of this study was to evaluate the effectiveness of green roofs in the reduction of the urban heat island (UHI) effect and CO2 emissions. These effects consider decreased energy consumption for space cooling, and the amount of water needed for evapotranspiration on the green roofs. A coupled urban canopy/building energy model (CM-BEM) was utilized to simulate the effectiveness of green roofs. The amount of water needed for evapotranspiration was calculated by using latent heat flux, which was derived from the results of roof surface heat balance calculations. The effect of green roofs on CO2 emissions was determined based on their effectiveness to reduce the energy demand for space cooling, calculated by air-conditioning load simulation. We calculated the CO2 emissions from powering the pumps and the use of tap water, when the necessary amount of water was supplied by watering. Finally, the relationships between amount of water, UHI mitigation, and CO2 emissions were determined.
Yujiro Hirano; Tomohiko Ihara; Kei Gomi; Tsuyoshi Fujita. Simulation-Based Evaluation of the Effect of Green Roofs in Office Building Districts on Mitigating the Urban Heat Island Effect and Reducing CO2 Emissions. Sustainability 2019, 11, 2055 .
AMA StyleYujiro Hirano, Tomohiko Ihara, Kei Gomi, Tsuyoshi Fujita. Simulation-Based Evaluation of the Effect of Green Roofs in Office Building Districts on Mitigating the Urban Heat Island Effect and Reducing CO2 Emissions. Sustainability. 2019; 11 (7):2055.
Chicago/Turabian StyleYujiro Hirano; Tomohiko Ihara; Kei Gomi; Tsuyoshi Fujita. 2019. "Simulation-Based Evaluation of the Effect of Green Roofs in Office Building Districts on Mitigating the Urban Heat Island Effect and Reducing CO2 Emissions." Sustainability 11, no. 7: 2055.
A parametric model was built to analyse electricity sensitivity to solar radiation. Illumination sensitivity was highest during the early mornings and evenings. The designed parametric model is useful for understanding residential city blocks. The results can be used to design energy-saving measures controlling solar radiation.
Yuki Hashimoto; Yukitaka Ohashi; Minako Nabeshima; Yoshinori Shigeta; Yukihiro Kikegawa; Tomohiko Ihara. Sensitivity of electricity consumption to air temperature, air humidity and solar radiation at the city-block scale in Osaka, Japan. Sustainable Cities and Society 2018, 45, 38 -47.
AMA StyleYuki Hashimoto, Yukitaka Ohashi, Minako Nabeshima, Yoshinori Shigeta, Yukihiro Kikegawa, Tomohiko Ihara. Sensitivity of electricity consumption to air temperature, air humidity and solar radiation at the city-block scale in Osaka, Japan. Sustainable Cities and Society. 2018; 45 ():38-47.
Chicago/Turabian StyleYuki Hashimoto; Yukitaka Ohashi; Minako Nabeshima; Yoshinori Shigeta; Yukihiro Kikegawa; Tomohiko Ihara. 2018. "Sensitivity of electricity consumption to air temperature, air humidity and solar radiation at the city-block scale in Osaka, Japan." Sustainable Cities and Society 45, no. : 38-47.
Jun Nakatani; Kiyotaka Tahara; Kenichi Nakajima; Ichiro Daigo; Hideaki Kurishima; Yuki Kudoh; Kazuyo Matsubae; Yasuhiro Fukushima; Tomohiko Ihara; Yasunori Kikuchi; Asako Nishijima; Yuichi Moriguchi. A graph theory-based methodology for vulnerability assessment of supply chains using the life cycle inventory database. Omega 2018, 75, 165 -181.
AMA StyleJun Nakatani, Kiyotaka Tahara, Kenichi Nakajima, Ichiro Daigo, Hideaki Kurishima, Yuki Kudoh, Kazuyo Matsubae, Yasuhiro Fukushima, Tomohiko Ihara, Yasunori Kikuchi, Asako Nishijima, Yuichi Moriguchi. A graph theory-based methodology for vulnerability assessment of supply chains using the life cycle inventory database. Omega. 2018; 75 ():165-181.
Chicago/Turabian StyleJun Nakatani; Kiyotaka Tahara; Kenichi Nakajima; Ichiro Daigo; Hideaki Kurishima; Yuki Kudoh; Kazuyo Matsubae; Yasuhiro Fukushima; Tomohiko Ihara; Yasunori Kikuchi; Asako Nishijima; Yuichi Moriguchi. 2018. "A graph theory-based methodology for vulnerability assessment of supply chains using the life cycle inventory database." Omega 75, no. : 165-181.
Kotaro Kawajiri; Tomohiko Ihara; Hiroki Hatayama; Kiyotaka Tahara. Revealing hidden CO2 impacts from consequential consumption by matrix analysis: Application to Japanese single households. Journal of Cleaner Production 2018, 172, 582 -590.
AMA StyleKotaro Kawajiri, Tomohiko Ihara, Hiroki Hatayama, Kiyotaka Tahara. Revealing hidden CO2 impacts from consequential consumption by matrix analysis: Application to Japanese single households. Journal of Cleaner Production. 2018; 172 ():582-590.
Chicago/Turabian StyleKotaro Kawajiri; Tomohiko Ihara; Hiroki Hatayama; Kiyotaka Tahara. 2018. "Revealing hidden CO2 impacts from consequential consumption by matrix analysis: Application to Japanese single households." Journal of Cleaner Production 172, no. : 582-590.
The purpose of this research is to identify at what extent e-book reading reduces global warming potential (GWP) of book reading activities relative to that of reading only paper books. Past studies assume e-books and paper books are interchangeable during consumption, but adopting e-book reading can alter reading patterns in reality. This research comparatively assessed the GWP of reading only paper books and that of reading pattern of after e-reader adoption of consumer segments. We computed GWP of book reading activities of consumer segments that include a life cycle of paper book, e-book, and e-book reading device. Two e-book devices were considered: a designated e-book device (e-reader) and a tablet. The functional units are book reading activities per person and per person-book, which account the number of books purchased or acquired and the reading hours per person. We collected data through a web survey in the USA. Consumer segmentation was performed by analyzing the level of importance in the aspects of book reading activities as a measurement variable. To observe the changes in reading patterns upon e-reader adoption within the same population, we conducted a 3-month social experiment involving e-readers in the USA. Adopting e-readers was discovered to reduce both the GWP per person and the GWP per person-book of book reading activities. The GWP of e-books read with an e-reader and the GWP of paper books were found to break even at 4.7 books per year, provided consumers read less than 11 h a day. According to the web survey, e-reader users purchase more than seven e-books annually on average, which resulted in a smaller GWP per person-book relative to that of one paper book. Furthermore, the GWP per person in the social experiment was smaller for e-reader adopters than those who only read paper books because they substituted e-books for paper books. The overall book reading volume remains unchanged upon e-reader adoption. Adoption of e-readers reduces the GWP from book reading activities with only paper books, provided more than 4.7 paper books are substituted by e-books annually, and provided consumers’ total consumption volume remain unchanged. E-reader adopters read sufficient number of e-books to break even with paper books. However, most e-reader adopters are yet to fully abandon paper books for e-books. Analyzing the differences in the reading experience between e-books and paper books is a future task.
Eri Amasawa; Tomohiko Ihara; Keisuke Hanaki. Role of e-reader adoption in life cycle greenhouse gas emissions of book reading activities. The International Journal of Life Cycle Assessment 2017, 23, 1874 -1887.
AMA StyleEri Amasawa, Tomohiko Ihara, Keisuke Hanaki. Role of e-reader adoption in life cycle greenhouse gas emissions of book reading activities. The International Journal of Life Cycle Assessment. 2017; 23 (9):1874-1887.
Chicago/Turabian StyleEri Amasawa; Tomohiko Ihara; Keisuke Hanaki. 2017. "Role of e-reader adoption in life cycle greenhouse gas emissions of book reading activities." The International Journal of Life Cycle Assessment 23, no. 9: 1874-1887.
Eri Amasawa; Tomohiko Ihara. The right place to grow rice for the Japanese market: comparative analysis of greenhouse gas emissions of rice cultivation in Japan and the United States. International Journal of Agricultural Sustainability 2017, 15, 1 -12.
AMA StyleEri Amasawa, Tomohiko Ihara. The right place to grow rice for the Japanese market: comparative analysis of greenhouse gas emissions of rice cultivation in Japan and the United States. International Journal of Agricultural Sustainability. 2017; 15 (4):1-12.
Chicago/Turabian StyleEri Amasawa; Tomohiko Ihara. 2017. "The right place to grow rice for the Japanese market: comparative analysis of greenhouse gas emissions of rice cultivation in Japan and the United States." International Journal of Agricultural Sustainability 15, no. 4: 1-12.
In this study, we validated urban air temperature and electricity demand by a year-round numerical simulation using a regional climate model coupled with an urban canopy model and a building energy model (RCM-UCM+BEM) in the Asian megacity, Osaka, which is the largest metropolis in Japan after Tokyo. The control simulation (CTRL), which was based on the use of central air-conditioning (AC) systems, reproduced the surface air temperatures observed in Osaka City in the summer cooling and interim seasons, but underestimated midnight to morning temperatures by over 2 °C in the winter heating season. In addition, the CTRL significantly overestimated the electricity demand in Osaka City in both the cooling and heating seasons, when the AC load was increased. These errors were likely due to the overestimation of AC use in the CTRL model because, in Japan, central AC systems are not used in business and residential areas, where individual AC units are mainly used. To prevent this overestimation, we introduced three new parameters to consider the use of partial AC systems in the model. The results of the new numerical experiment remarkably reduced the underestimation of temperature and the overestimation of electricity demand. This suggests that the RCM-UCM+BEM modified by this study is effective for not only reproducing the current status of seasonal urban air temperature and electricity demand in Osaka, but also for projecting the future situation in other mega cities.
Yuya Takane; Yukihiro Kikegawa; Masayuki Hara; Tomohiko Ihara; Yukitaka Ohashi; Sachiho Adachi; Hiroaki Kondo; Kazuki Yamaguchi; Naoki Kaneyasu. A climatological validation of urban air temperature and electricity demand simulated by a regional climate model coupled with an urban canopy model and a building energy model in an Asian megacity. International Journal of Climatology 2017, 37, 1035 -1052.
AMA StyleYuya Takane, Yukihiro Kikegawa, Masayuki Hara, Tomohiko Ihara, Yukitaka Ohashi, Sachiho Adachi, Hiroaki Kondo, Kazuki Yamaguchi, Naoki Kaneyasu. A climatological validation of urban air temperature and electricity demand simulated by a regional climate model coupled with an urban canopy model and a building energy model in an Asian megacity. International Journal of Climatology. 2017; 37 ():1035-1052.
Chicago/Turabian StyleYuya Takane; Yukihiro Kikegawa; Masayuki Hara; Tomohiko Ihara; Yukitaka Ohashi; Sachiho Adachi; Hiroaki Kondo; Kazuki Yamaguchi; Naoki Kaneyasu. 2017. "A climatological validation of urban air temperature and electricity demand simulated by a regional climate model coupled with an urban canopy model and a building energy model in an Asian megacity." International Journal of Climatology 37, no. : 1035-1052.
Daisuke Narumi; Tomohiko Ihara; Sanae Fukuda; 大典 鳴海. STUDY ON THE IMPACT FOR FATIGUE DUE TO CHANGING URBAN OUTDOOR TEMPERATURE. AIJ Journal of Technology and Design 2017, 23, 563 -566.
AMA StyleDaisuke Narumi, Tomohiko Ihara, Sanae Fukuda, 大典 鳴海. STUDY ON THE IMPACT FOR FATIGUE DUE TO CHANGING URBAN OUTDOOR TEMPERATURE. AIJ Journal of Technology and Design. 2017; 23 (54):563-566.
Chicago/Turabian StyleDaisuke Narumi; Tomohiko Ihara; Sanae Fukuda; 大典 鳴海. 2017. "STUDY ON THE IMPACT FOR FATIGUE DUE TO CHANGING URBAN OUTDOOR TEMPERATURE." AIJ Journal of Technology and Design 23, no. 54: 563-566.
著者らが開発した都市気象・建物エネルギー連成数値モデルWRF-CM-BEMについて,都市の気象と太陽光発電を加味した電力需給の同時予測への適用に向けた検証を行った.都市域での従来に無い高解像度の全天日射量に加え,多地点の地上気温と変電所供給区域毎の電力需要量を2013年度に大阪で通年計測し,それらのモデルによる夏季の再現性を検証した.結果,日射量では晴天時実測値を誤差7%で再現可能な一方で曇天時には過大評価が顕著であったが,実測された都市域日射の空間不均一性の定性的傾向をモデルは概ね再現した.地上気温の再現精度は米国の類似モデルを上回り良好であり,電力需要では業務街の実需要を再現可能な一方で住宅街では40%程度の過大需要がシミュレートされた.検証を通じモデル改良の方向性を明確化できた.
Yukihiro Kikegawa; Youhei Yamakawa; Eriya Tokutake; Yukitaka Ohashi; Yuya Takane; Tomohiko Ihara; Minako Nabeshima. VALIDATION OF A NUMERICAL URBAN WEATHER FORECASTING MODEL COUPLED WITH A BUILDING ENERGY MODEL IN TERMS OF THE REPRODUCIBILITY OF SOLAR IRRADIANCE AND ELECTRICITY DEMAND. Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research) 2017, 73, 57 -69.
AMA StyleYukihiro Kikegawa, Youhei Yamakawa, Eriya Tokutake, Yukitaka Ohashi, Yuya Takane, Tomohiko Ihara, Minako Nabeshima. VALIDATION OF A NUMERICAL URBAN WEATHER FORECASTING MODEL COUPLED WITH A BUILDING ENERGY MODEL IN TERMS OF THE REPRODUCIBILITY OF SOLAR IRRADIANCE AND ELECTRICITY DEMAND. Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research). 2017; 73 (2):57-69.
Chicago/Turabian StyleYukihiro Kikegawa; Youhei Yamakawa; Eriya Tokutake; Yukitaka Ohashi; Yuya Takane; Tomohiko Ihara; Minako Nabeshima. 2017. "VALIDATION OF A NUMERICAL URBAN WEATHER FORECASTING MODEL COUPLED WITH A BUILDING ENERGY MODEL IN TERMS OF THE REPRODUCIBILITY OF SOLAR IRRADIANCE AND ELECTRICITY DEMAND." Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research) 73, no. 2: 57-69.
Eri Amasawa; Tomohiko Ihara; Takashi Ohta; Keisuke Hanaki. Life cycle assessment of organic light emitting diode display as emerging materials and technology. Journal of Cleaner Production 2016, 135, 1340 -1350.
AMA StyleEri Amasawa, Tomohiko Ihara, Takashi Ohta, Keisuke Hanaki. Life cycle assessment of organic light emitting diode display as emerging materials and technology. Journal of Cleaner Production. 2016; 135 ():1340-1350.
Chicago/Turabian StyleEri Amasawa; Tomohiko Ihara; Takashi Ohta; Keisuke Hanaki. 2016. "Life cycle assessment of organic light emitting diode display as emerging materials and technology." Journal of Cleaner Production 135, no. : 1340-1350.
To achieve a low-carbon society, it is crucial to make the transition away from wasteful lifestyles that are shaped by mass production/mass consumption towards low-carbon lifestyles. Research in the field of urban environmental studies examining human behavioral factors affecting energy consumption, has mostly focused on CO2 emissions relating to direct energy consumption, such as the use of air conditioners and water heaters. As CO2 emissions from the industrial sector are greater than those from the residential and transportation sectors in Japan, it would be prudent for consumers to work on reducing CO2 emissions relating to products and services. In an effort to provide some basic research to achieve the aforementioned objectives, this study looked at statistical data from sources such as the Japanese Family Income and Expenditure Survey and the Japanese National Survey of Family Income and Expenditure to estimate direct and indirect CO2 emissions relating to daily expenditures and consumption. As a case study, we selected a sample denizen to calculate the CO2 emissions relating to daily living. Based on the obtained results, we examined the lifestyle and consumption patterns and their relation to CO2 emissions. The results suggest that while it is still important for consumers to reduce their direct energy consumption in an effort to create a low-carbon society, there is still potential for indirect CO2 emission reductions in areas of production and consumption.
Yujiro Hirano; Tomohiko Ihara; Yukiko Yoshida. Estimating residential CO2 emissions based on daily activities and consideration of methods to reduce emissions. Building and Environment 2016, 103, 1 -8.
AMA StyleYujiro Hirano, Tomohiko Ihara, Yukiko Yoshida. Estimating residential CO2 emissions based on daily activities and consideration of methods to reduce emissions. Building and Environment. 2016; 103 ():1-8.
Chicago/Turabian StyleYujiro Hirano; Tomohiko Ihara; Yukiko Yoshida. 2016. "Estimating residential CO2 emissions based on daily activities and consideration of methods to reduce emissions." Building and Environment 103, no. : 1-8.
Yukitaka Ohashi; Tomohiko Ihara; Yukihiro Kikegawa; Nanami Sugiyama. Numerical simulations of influence of heat island countermeasures on outdoor human heat stress in the 23 wards of Tokyo, Japan. Energy and Buildings 2016, 114, 104 -111.
AMA StyleYukitaka Ohashi, Tomohiko Ihara, Yukihiro Kikegawa, Nanami Sugiyama. Numerical simulations of influence of heat island countermeasures on outdoor human heat stress in the 23 wards of Tokyo, Japan. Energy and Buildings. 2016; 114 ():104-111.
Chicago/Turabian StyleYukitaka Ohashi; Tomohiko Ihara; Yukihiro Kikegawa; Nanami Sugiyama. 2016. "Numerical simulations of influence of heat island countermeasures on outdoor human heat stress in the 23 wards of Tokyo, Japan." Energy and Buildings 114, no. : 104-111.
Daisuke Narumi; Tomohiko Ihara; Sanae Fukuda. STUDY ON THE IMPACT FOR SLEEP DISTURBANCE DUE TO CHANGING URBAN OUTDOOR TEMPERATURE. AIJ Journal of Technology and Design 2016, 22, 1045 -1048.
AMA StyleDaisuke Narumi, Tomohiko Ihara, Sanae Fukuda. STUDY ON THE IMPACT FOR SLEEP DISTURBANCE DUE TO CHANGING URBAN OUTDOOR TEMPERATURE. AIJ Journal of Technology and Design. 2016; 22 (52):1045-1048.
Chicago/Turabian StyleDaisuke Narumi; Tomohiko Ihara; Sanae Fukuda. 2016. "STUDY ON THE IMPACT FOR SLEEP DISTURBANCE DUE TO CHANGING URBAN OUTDOOR TEMPERATURE." AIJ Journal of Technology and Design 22, no. 52: 1045-1048.
Yuki Hashimoto; Minako Nabeshima; Yoshinori Shigeta; Yukihiro Kikegawa; Tomohiko Ihara. ANALYSIS AND DISCUSSION OF SENSITIVITIES OF ELECTRICITY CONSUMPTION TO OUTDOOR AIR TEMPERATURE AND OUTDOOR AIR HUMIDITY IN BUSINESS AND RESIDENTIAL DISTRICTS IN CITY-BLOCK-SCALE. Journal of Environmental Engineering (Transactions of AIJ) 2016, 81, 827 -834.
AMA StyleYuki Hashimoto, Minako Nabeshima, Yoshinori Shigeta, Yukihiro Kikegawa, Tomohiko Ihara. ANALYSIS AND DISCUSSION OF SENSITIVITIES OF ELECTRICITY CONSUMPTION TO OUTDOOR AIR TEMPERATURE AND OUTDOOR AIR HUMIDITY IN BUSINESS AND RESIDENTIAL DISTRICTS IN CITY-BLOCK-SCALE. Journal of Environmental Engineering (Transactions of AIJ). 2016; 81 (727):827-834.
Chicago/Turabian StyleYuki Hashimoto; Minako Nabeshima; Yoshinori Shigeta; Yukihiro Kikegawa; Tomohiko Ihara. 2016. "ANALYSIS AND DISCUSSION OF SENSITIVITIES OF ELECTRICITY CONSUMPTION TO OUTDOOR AIR TEMPERATURE AND OUTDOOR AIR HUMIDITY IN BUSINESS AND RESIDENTIAL DISTRICTS IN CITY-BLOCK-SCALE." Journal of Environmental Engineering (Transactions of AIJ) 81, no. 727: 827-834.
Yukitaka Ohashi; Makoto Suido; Yukihiro Kikegawa; Tomohiko Ihara; Yoshinori Shigeta; Minako Nabeshima. Impact of seasonal variations in weekday electricity use on urban air temperature observed in Osaka, Japan. Quarterly Journal of the Royal Meteorological Society 2015, 142, 971 -982.
AMA StyleYukitaka Ohashi, Makoto Suido, Yukihiro Kikegawa, Tomohiko Ihara, Yoshinori Shigeta, Minako Nabeshima. Impact of seasonal variations in weekday electricity use on urban air temperature observed in Osaka, Japan. Quarterly Journal of the Royal Meteorological Society. 2015; 142 (695):971-982.
Chicago/Turabian StyleYukitaka Ohashi; Makoto Suido; Yukihiro Kikegawa; Tomohiko Ihara; Yoshinori Shigeta; Minako Nabeshima. 2015. "Impact of seasonal variations in weekday electricity use on urban air temperature observed in Osaka, Japan." Quarterly Journal of the Royal Meteorological Society 142, no. 695: 971-982.
We investigate the extent to which Japanese people can change their consumption and the corresponding environmental impact. We propose a new analytical framework with a rebound matrix that captures the monetary flow from potential savings to their respending (referred to as rebound). A questionnaire is used to derive the matrix. On average, respondents spent 3.4 million Yen annually, resulting in 12.4 tons of carbon dioxide (CO2) emissions in their daily lives. The survey results suggest that acceptable spending reductions would correspond to a CO2 emissions reduction of nearly 6%. However, the CO2 emissions would increase by nearly the same amount when the respondents respend their savable money (rebound CO2 emissions). The annual CO2 emissions and the annually reducible CO2 emissions both increase with the increase in annual expenditure. Consequently, the net CO2 emissions also increase with the increase in annual expenditure. The rebound spending is approximated using the rebound matrix. Finally, it is suggested that the net CO2 emissions can be reduced through lifestyle changes whereby spending on energy items is reduced and the resulting savings are spent on telecommunication, clothes, shoes, education, and housing.
Kotaro Kawajiri; Tomohiro Tabata; Tomohiko Ihara. Using a Rebound Matrix to Estimate Consumption Changes from Saving and its Environmental Impact in Japan. Journal of Industrial Ecology 2015, 19, 564 -574.
AMA StyleKotaro Kawajiri, Tomohiro Tabata, Tomohiko Ihara. Using a Rebound Matrix to Estimate Consumption Changes from Saving and its Environmental Impact in Japan. Journal of Industrial Ecology. 2015; 19 (4):564-574.
Chicago/Turabian StyleKotaro Kawajiri; Tomohiro Tabata; Tomohiko Ihara. 2015. "Using a Rebound Matrix to Estimate Consumption Changes from Saving and its Environmental Impact in Japan." Journal of Industrial Ecology 19, no. 4: 564-574.
It has been recognized that an increase in outdoor ambient temperatures has a negative impact on health, particularly fatigue and sleep quality; however, the relationship among fatigue, sleep quality, and air temperature has yet to be sufficiently elucidated.To examine whether fatigue and sleep quality in a healthy Japanese population were affected by rising air temperature at three time points in summer and to investigate the confounding factors for fatigue.A total of 602 healthy volunteers in Osaka, Japan, participated in a survey that was conducted at the end of July, August, and September in 2010. The questionnaire consisted of four sections; demographic variables, accommodation status, fatigue, and sleep quality. We used the Chalder fatigue scale for assessment of fatigue, and the Japanese version of the Pittsburgh Sleep Quality Index (PSQI) for assessment of sleep quality.The fatigue score was positively correlated with the sleep quality score in the total cohort. All the questionnaires at the three time points were completed by 162 participants. There were significant differences in fatigue scores among the surveys. We stratified the subjects into two groups of good and poor sleepers using a cutoff value of the PSQI. The good sleepers did not show differences in fatigue score regardless of the change in air temperature. However, the fatigue score of poor sleepers was greater at higher air temperatures. The use of air conditioners, accommodation type, and subject's age were confounding factors for fatigue.High air temperatures in summer increased fatigue in healthy volunteers, especially those with poor sleep patterns, depending on the use of air conditioners, accommodation status, and subject's age.
Hisako Fujii; Sanae Fukuda; Daisuke Narumi; Tomohiko Ihara; Yasuyoshi Watanabe. Fatigue and sleep under large summer temperature differences. Environmental Research 2015, 138, 17 -21.
AMA StyleHisako Fujii, Sanae Fukuda, Daisuke Narumi, Tomohiko Ihara, Yasuyoshi Watanabe. Fatigue and sleep under large summer temperature differences. Environmental Research. 2015; 138 ():17-21.
Chicago/Turabian StyleHisako Fujii; Sanae Fukuda; Daisuke Narumi; Tomohiko Ihara; Yasuyoshi Watanabe. 2015. "Fatigue and sleep under large summer temperature differences." Environmental Research 138, no. : 17-21.
We aimed to identify the effect of environmental factors on sleep in the summertime in Japan. A self-reported questionnaire survey was conducted in Japan. Age of participants ranged from 20 to 70 years. The mean Pittsburgh Sleep Quality Index (PSQI) score was 4.9 (±2.7), and 123 (35.0%) participants had scores of >5. According to the results of multivariate logistic regression analysis, the adjusted odds ratio (aOR) for PSQI scores of >5 without installation of air conditioner was 1.8 (95% confidence interval [CI], 1.0-3.3; P<.05), use of a light bulb was 3.7 (95% CI, 1.1-12.6; P<.05), and noise was 2.1 (95% CI, 1.1-4.1; P<.05) after controlling for several confounding variables. Difficulty initiating sleep (DIS) was associated with installation of an air conditioner (1 [reference] to 3 [aOR, 2.5 {95% CI, 1.2-5.1}] and 4 [aOR, 2.8 {95% CI, 1.1-7.1}]) and noise (1 [reference] to 3 [aOR, 2.4 {95% CI, 1.0-5.9}] and 4 [aOR, 8.8 {95% CI, 3.1-25.0}]). Difficulty maintaining sleep (DMS) was associated with installation of a fan (1 [reference] to 2 [aOR, 0.4 {95% CI, 0.2-0.8}] and noise (1 [reference] to 3 [aOR, 2.3 {95% CI, 1.0-5.3}]) after controlling for several confounding variables. Our finding using analysis of the association between residential environments and subjective sleep statuses, which determined that the installation of an air conditioner and lighting equipment might affect sleep, may be useful to discuss sleep environments and improve sleep quality.
Momoko Kayaba; Tomohiko Ihara; Hiroyuki Kusaka; Satoru Iizuka; Kenji Miyamoto; Yasushi Honda. Association between sleep and residential environments in the summertime in Japan. Sleep Medicine 2014, 15, 556 -564.
AMA StyleMomoko Kayaba, Tomohiko Ihara, Hiroyuki Kusaka, Satoru Iizuka, Kenji Miyamoto, Yasushi Honda. Association between sleep and residential environments in the summertime in Japan. Sleep Medicine. 2014; 15 (5):556-564.
Chicago/Turabian StyleMomoko Kayaba; Tomohiko Ihara; Hiroyuki Kusaka; Satoru Iizuka; Kenji Miyamoto; Yasushi Honda. 2014. "Association between sleep and residential environments in the summertime in Japan." Sleep Medicine 15, no. 5: 556-564.