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Hydrogen energy technologies are envisioned to play a critical supporting role in global decarbonisation. While low-carbon hydrogen is primarily targeted for reducing industrial emissions, alongside decarbonising parts of the transport sector, environmental benefits could also be achieved in the residential context. Presently, gas-dependent countries such as Japan and the United Kingdom are assessing the feasibility of deploying hydrogen home appliances, as part of their national energy strategies. However, prospects for the transition will hinge on consumer acceptance, alongside an array of other socio-technical factors. To support potential ambitions for large-scale and sustained technology diffusion, this study advances a Unified Theory of Domestic Hydrogen Acceptance. Through an integrative, comparative literature review targeting hydrogen and domestic energy studies, the paper proposes a novel Domestic Hydrogen Acceptance Model (DHAM), which accounts for the cognitive and emotional dimensions of human perceptions. Through this dual interplay, the proposed framework can increase the predictive power of hydrogen acceptance models. [Display omitted] • A unified theory of domestic hydrogen acceptance is proposed. • Researchers should integrate multiple acceptance constructs into survey studies. • Comprehensive perceived risks, costs, and benefits predict attitudes toward hydrogen. • Cognitive and emotional processes influence perceptions of hydrogen homes. • Community-level factors should be incorporated into hydrogen acceptance research. [ABSTRACT FROM AUTHOR]

This paper analysed CO 2 emission pathways for the Japanese iron and steel industry towards 2030, taking into account the likely development of process capacities that could flexibly adapt to a range of projected future crude steel production levels (“optimal capacities”) while maintaining minimum capacity utilisation rates. Coke and pig iron production capacities were optimised to the levels that enable flexible operation for 90–120 Mt-crude steel/y, compared to 110 Mt/y in 2010. Operational constraints were applied to the capacity utilisation rates (minimum of 85%) and the maximum use of coke and pig iron substitutes. This paper also assessed the implications of the aforementioned flexible operation across a range of crude steel production levels on the future scrap balances. This study calculated the optimal capacities for coke ovens and blast furnaces in 2030 to be 29 Mt-coke/y (compared to 43 Mt/y in 2010) and 83 Mt-pig iron/y (compared to 90 Mt/y in 2010). Under these optimal capacities and the aforementioned range for crude steel production levels, the projected total CO 2 emissions were 4–21% below 2010 levels. If the 2030 production level remains at 105 Mt/y, which equals the 2015 production level and the 1973–2015 average, the total emissions will be 9–16% below 2010 levels, depending on the level of emissions reduction effort. These results indicate that the industry is likely to considerably overachieve its voluntary emissions reduction target for 2030 (0.1% below 2010 levels). Moreover, it was found that the lifetime extensions for existing blast furnaces and coke ovens have limited impact on CO 2 emissions while significantly reducing the investment needs. The study also showed that the low crude steel production (90 Mt/y) combined with high pig iron and coke consumption levels to maintain minimum capacity utilisation rates may lead not only to an increase in specific CO 2 emissions per tonne of crude steel but also to a net export of obsolete scrap up to 17 Mt, which is nearly twice the historical high. Towards 2030, Japan would need to consider not only opportunities to maximize the use of steel scrap but also the development of an extended steel scrap trade infrastructure. [ABSTRACT FROM AUTHOR]

Abstract: Flame retardants are used in polymers to reduce the flammability of building materials, electric appliances, fabric and papers. In recent years, organophosphate flame retardants have been used as substitutes for polybrominated flame retardants (BFRs). In Japan, the amount of organophosphate flame retardants used in 2001 was about five times more than in 2000. Recently, several studies have shown the health concerns for some organophosphate flame retardants. Little research has been performed on the emission of organophosphate flame retardants, especially the relationship between content and emissions. In this study, a new type of passive sampler was developed to measure emissions of organophosphate flame retardants from plastic materials. With this sampler, emissions from polyvinyl chloride wallpaper samples with different content of tris(2-chloroisopropyl)phosphate (TCPP) at different temperatures were examined. The observed maximum emissions of TCPP from 1, 3, 5, 10 and 20 w/w% content wallpaper materials were 262. 3, 452. 6, 644. 8, 1119. 1 and 2166. 8μgm−2 h−1, respectively. Emissions from 5% TCPP content materials at 40 and 60°C were 1135. 7 and 2841. 2μgm−2 h−1, respectively. A significantly positive correlation between the flux of TCPP and the TCPP content of the wallpaper samples was observed. A linear relationship was found between the inverse of temperature and the logarithm of TCPP emission. The results imply that the use of materials with a high organophosphate flame retardant content can lead to high emission rates in high-temperature indoor environments. [Copyright &y& Elsevier]

Polyethylene (PE) and polypropylene (PP) can be synthesized from biomass through dehydration, dimerization, and metathesis reactions from ethanol or methanol-to-olefin reaction of synthesis gas. This paper examines the socioeconomic aspects of such biomass-derived resin production, which are composed of environmental impacts quantified by life cycle analysis (LCA) and the structure of generated value flows specified by structural path analysis (SPA) based on a Japanese input–output table. Missing inventory data were estimated by process simulation using Aspen Plus™ and Aspen HYSYS™ with design information extracted from the literature, patents, and design heuristics. LCA based on actual and demonstration plants with process simulation shows the environmental advantage of biomass-derived resins on greenhouse gas (GHG) emissions reduction. PE production has the largest effect on GHG emissions reduction, followed by bioethanol from a gasoline mixture, and PP. The uncertainties in agricultural processes also influence the potential application of international and domestic bioethanol production and synthesis gas obtained from the gasification of waste woods. According to SPA results for gasoline, PE, PP, and plastic products, the cyclicality of resins and plastic products, which was quantitatively analyzed as the total cyclic cash flows from target products to final demands, is much larger than that of gasoline. Based on these results, biomass-derived resin production has the potential to increase added values in an economy, with a corresponding decrease in GHG emissions. [ABSTRACT FROM AUTHOR]

Abstract: The environmental impact of CO2 emissions has attracted increasing attention in recent years, which has redefined the modal choice between air and rail transport. Transport service provision via railway involves less marginal environmental damage than air transport, yet it entails a higher emissions burden in its infrastructure construction stage. This paper empirically investigates the environmental burden of these two transport modes by taking into account the CO2 emissions from both transport service provision and infrastructure construction. Using a panel data set from 1999 to 2007 for three Japanese railway companies and the Japanese air transport industry, which are treated as decision-making units (DMUs), this paper estimates the social efficiency of these DMUs via a nonparametric productivity measurement method that incorporates economic bads as undesirable outputs. The aviation industry is shown to be efficient, whereas results for the railway industry are mixed: JR East is efficient, JR West is inefficient throughout the observation period, and JR Tokai substantially improved its efficiency during the period to become an efficient company in 2007. [Copyright &y& Elsevier]

Abstract: The observation of ULF/ELF electromagnetic waves in the frequency range below 50Hz has been continued at Nakatsugawa (in the Gifu prefecture), Japan since 1998. This paper summarizes anomalous Schumann resonance (SR) phenomena and SR-like line emissions observed at Nakatsugawa in possible association with recent nearby earthquakes (EQs) (the 2004 Mid-Niigata prefecture and the 2007 Noto-Hanto (peninsula) EQs), which have been already described in detail by . The intensity of particular modes of SR increased before these large EQs and the excitation of other anomalous SR-like line emissions also existed at the frequency shifted by about 2Hz from the typical SR modes. Since temporal changes of the anomalous SR modes and line emissions are synchronous in time, there might be a possibility that the line emission is a consequence of the anomalous SR. In this paper we propose an interpretation of those anomalous phenomena in terms of excitation of gyrotropic waves due to input wave from below with a band from 15 to 20Hz as an exciter. The theoretical computational results seem to be generally consistent with the observational finding. [ABSTRACT FROM AUTHOR]

Abstract: This study examines the economics of energy-efficiency strategies for reducing CO2 emissions in the residential sector in Japan from the perspective of regional characteristics. For this study, the residential sector in Iwate prefecture was selected as representative of rural areas in Japan. In order to promote purchases of energy-efficient consumer appliances, the prefectural government is presumed to reimburse purchasers a part of the cost difference between energy efficient and conventional appliances. This paper begins with a discussion of the prefecture’s financial support for purchasers of energy efficient appliances and assumes that the payments come from prefectural government funds. This paper then looks at the effect of a carbon-tax refund on the reduction of CO2 emissions. The results show that, if half of the households use energy-efficient appliances, then CO2 emissions in the residential sector in the year 2020 will decreases from the BAU scenario, 0.726Mt-C to 0.674Mt-C. However, the Iwate prefectural government expends $105 million annually, which is 1.5% of the total tax revenue in the year 2003. The carbon-tax refund effectively encourages further reductions in CO2 emissions. Under the $20/tC carbon tax, proposed by the Ministry of the Environment, the carbon-tax refund leads to a reduction in residential CO2 emissions from 0.726Mt-C to 0.712Mt-C. [Copyright &y& Elsevier]

Abstract: Under the pressures of rapid industrialization and urbanization, many Asian countries are facing the challenge of reducing air pollution and CO2 emissions simultaneously while maintaining their economic growth. Under such a circumstance, a growing attention is focused on successful implementation of co-benefit policies that are designed to reduce both air pollutants and CO2 emissions. However, the concept of co-benefit policies must be developed further in order to identify its quantitative and qualitative validity, which can be assessed using a reliable methodology for the estimation of co-benefits and through clarification of the importance of this approach for stakeholders in urban environmental policy-making. Based on a systematic review of co-benefit research and air pollution control policies in Japan, we investigated the local air pollution control policy in Kawasaki City, one of the industrial centers of Japan, and confirmed that it has contributed both to the sharp decline of atmospheric sulfur dioxide (SO2) levels and to energy efficiency improvements in local industries. Our results suggest that preventive actions and local-scale compliance enforcement tools (that are uniquely designed and act as a form of agreement between government and individual firms) could contribute significantly to successful implementation of co-benefit policies in the long-term. We conclude our paper with a discussion of linkages between low-carbon technology innovations and policy designs that could further nurture co-benefits. [Copyright &y& Elsevier]

Abstract: Biogenic volatile organic compounds (BVOCs) are known to play an important role in atmospheric chemistry due to their high reactivity and high emission rates. Therefore, in recent decades, many efforts have been made to estimate the emission rates, composition and allocation of the BVOCs. Monoterpenes (MNTs) and sesquiterpenes (SQTs) are major groups of BVOCs and mainly emitted from coniferous trees. There is quite a few reports discussing the seasonality of basal emission rate, which is a normalized emission rate at a set of standard conditions (e.g. temperature, light intensity), of the BVOCs. Three field measurements were conducted using branch enclosure techniques to determine MNTs and SQTs emission measured from mature trees of Cryptomeria japonica and Chamaecyparis obtusa, which are the most dominant trees in Japan and account for about 40–50% of Japanese forest in leaf amount throughout the four seasons in southern Japan in 2010. The results are compared with the measurements for the same compound classes obtained at a suburban area of Tokyo, Japan in 2009. The seasonal variation in the basal emissions of MNTs from both tree species at Shiiba did not show significant seasonal changes. For both tree species, the variations in the basal emission of MNTs differ in the two sites, while those of SQTs showed relatively similar variations. Chemical composition of SQTs showed clear and continued seasonal variations, while MNTs did not show any clear seasonal variation for these tree species at both sites. It can be hypothesized that the emissions of BVOC classes (e.g. MNTs and SQTs) depend on leaf age. In this paper, we discuss about the seasonal variations in the basal emission rates and chemical compositions of BVOCs obtained from the two dominant coniferous tree species in Japan based on nine field measurement campaigns conducted at two different sites. [Copyright &y& Elsevier]

Abstract: Decomposition methodologies are requisite to identify the sources of changes in energy use or carbon dioxide emissions. This paper is an inquiry into the theoretical properties of such decomposition methodologies. The study first presents our new decomposition methodology – the Multiple Calibration Decomposition Analysis (MCDA) – as a tool for the investigation. Then, it theoretically reexamines an established decomposition methodology – the Structural Decomposition Analysis proposed by . Subsequently, the study empirically investigates the properties of both methodologies, applying them to an actual case: the changes in energy use and carbon dioxide emissions in Japan during the oil crises period, when the oil price had a significant influence on the economy. The result shows that understanding the theoretical properties of decomposition methodologies is essential for a precise interpretation of empirical results. [Copyright &y& Elsevier]

Abstract: Non-methane hydrocarbons (NMHCs) are known to have an important role on air quality due to their high reactivity. NMHC analysis has been performed on 148 ambient air samples collected at five different sites in the Kanto area (Tokyo metropolitan area and surrounding six prefectures) of Japan in summer and winter of 2008, and fifty NMHCs have been determined and quantified. A field measurement campaign has been conducted at one of the busiest intersections in Tokyo metropolitan area in winter of 2008. NMHC emissions are evaluated through comparison of distributions of individual NMHCs emitted from motor vehicles, which are estimated from the measurements, with those determined from the current emissions inventory. The comparison revealed that the measured distributions of acetylene, ethylene and toluene showed a good agreement with those estimated from the emissions inventory (the values estimated from the measurements are a factor of 1.5, 0.56 and 2.3 larger than the emissions inventory in median, respectively), however, propane and isobutane are found to be significantly underestimated in the emissions inventory (the measured values were a factor of 18 and 5.1 larger than the emissions inventory, respectively). The significant underestimate of propane can be explained by that the current emissions inventory does not consider emissions from liquefied propane gas (LPG) fueled vehicles. However, for isobutane, reasons for the underestimate are still unclear. Another field measurement has been conducted in summer of 2008, where the air samples have been collected at three different sites on the ground and by a helicopter as well. Remarkable high concentrations of 1-butene and cis- and trans-2-butenes have been sporadically observed in the samples collected at Urayasu in the coastal area of Tokyo bay. Calculated propylene equivalent (PE) concentrations of butenes revealed that those have a significantly important role in ozone formation when the air plume is affected by emissions from their emission sources. The PE concentrations of butenes varied from 0.1 to 39 ppbC, and accounted for 1.5–75% of total PE concentrations at Urayasu. Most of the continuous air quality monitoring stations does not record concentrations of individual hydrocarbons, therefore, the importance of reactive and low concentration hydrocarbon such as butenes might be overlooked in the current emissions inventory and/or air quality model. In this paper, the reliability of NMHC emissions is evaluated based on the field measurements. Their possible impacts on air quality in the Kanto area are discussed as well, based on the calculated propylene equivalent concentrations. [Copyright &y& Elsevier]

Abstract: A model is developed that simulates nationwide energy consumption of the residential sector by considering the diversity of household and building types. Since this model can simulate the energy consumption for each household and building category by dynamic energy use based on the schedule of the occupants’ activities and a heating and cooling load calculation model, various kinds of energy-saving policies can be evaluated with considerable accuracy. In addition, the average energy efficiency of major electric appliances used in the residential sector and the percentages of housing insulation levels of existing houses is predicted by the “stock transition model.” In this paper, energy consumption and CO2 emissions in the Japanese residential sector until 2025 are predicted. For example, as a business – as-usual (BAU) case, CO2 emissions will be reduced by 7% from the 1990 level. Also evaluated are mitigation measures such as the energy efficiency standard for home electric appliances, thermal insulation code, reduction of standby power, high-efficiency water heaters, energy-efficient behavior of occupants, and dissemination of photovoltaic panels. [Copyright &y& Elsevier]

Abstract: This paper discusses voluntary CO2 emissions reduction schemes and, in particular focuses on the voluntary plan by the Japanese airline industry. Econometric analysis identifies statistically significant improvement of 3–4% in CO2 emissions intensity (CO2/RPK) subsequent to initiation of the voluntary plan in 1998. [Copyright &y& Elsevier]

This paper examines the potential of integrated waste and utility power management over the mid-term planning horizon in Japan. Energy recovery and CO2 emission reduction were estimated under two situations: (1) energy recovery efforts within the current waste management/power generation framework and (2) integrated waste management with sewage treatment systems and electric power industries. Scenario simulation results showed that under the current policy framework it is not feasible to achieve large energy recovery and CO2 emission reduction, while the integrated waste management scenarios show the potential of large energy recovery which is equivalent to about an 18 million t-CO2 emission reduction. The utilization of dry wastes for power generation at existing fossil power stations is significant in achieving the result. We also consider the effects of the ‘CO2 emission per GW generated’ for electric power generation on the total CO2 emission reduction because it varies by country and assumptions selected. Although this research did not include an economic analysis, based on estimated CO2 emissions and energy recovery, the integrated scenarios indicate a large potential in countries that have high dependence of fossil power generation and relatively low power generation efficiency. [Copyright &y& Elsevier]

To elucidate the macro-structure of the PM2.5 emissions generated by Japan''s economic activities, this paper presents an emission inventory of primary particles of PM2.5 with high sectoral resolution based on the Japanese Input–Output Tables, comprising some 400 sectors. These primary PM2.5 emissions were estimated by multiplying the estimated energy consumption associated with each fuel type by a PM10 emission factor incorporating the technological level of dust collection in each sector and the mass ratio of PM2.5 to PM10. Non-energy emissions from agricultural open burning were also determined. Total PM2.5 emissions in 2000 were 252 kt, 49% of which were due to mobile emission sources. Changes in total PM2.5 emissions between 1990 and 2000 were also calculated. This showed that a substantial increase in energy sector emissions due to rising coal consumption was offset by a sharp decline in emissions from road vehicles and shipping vessels, resulting in an overall decrease in total emissions. In addition, the emissions induced by economic demand in each sector were quantified by means of input–output analysis, which revealed that demand for construction, foods and communications and services constituted the principal causes of real domestic emissions. An assessment of sectoral contributions to PM2.5 emissions that takes into account the effects of human exposure, expressed as external costs, suggests that the contribution of transportation is greater than indicated on the grounds of direct emissions alone. [Copyright &y& Elsevier]

This paper analyzes the weekday–weekend differences of ozone, NO x (2) and non-methane hydrocarbons (NMHCs) in Tokyo and Osaka, Japan, from 2001 to 2004, in order to investigate the ozone weekend effect (OWE). Data were measured at 24 and 23 general air monitoring stations in Tokyo and Osaka, respectively. We focused on NO x and NMHCs to investigate the causes of OWE. Specifically, we examined weekday/weekend differences in the titration of O3 by NO and the photochemical ozone production. Weekend ozone concentrations were confirmed to be greater than those of weekdays during most periods in both Tokyo and Osaka, although precursor concentrations were higher on weekdays. Weekday ozone concentrations in Tokyo (other than during 2003) and Osaka decreased due to the reaction of O3 with NO, resulting in higher ozone but lower O x (the sum of O3 and NO2) concentrations on weekends than on weekends. In 2003 in Tokyo, however, the effect of the photochemical ozone production on weekends was larger than on weekdays, as determined by the comparison of ozone concentration increase versus NMHCs/NO x ratio and O x between weekdays and the weekend. The weekend NMHCs/NO x ratio would be in the boundary area between volatile organic compound (VOC)- and NO x -limited regime, so it is considered that the difference between 2003 and the other periods in Tokyo might be due to a change in precursor limitation. [Copyright &y& Elsevier]

Abstract: Carbon dioxide (CO2) emissions from the passenger-car sector in Japan are increasing rapidly and should be reduced cost-effectively in order to stabilize energy-related CO2 emissions in Japan. The purpose of the present paper is to clarify the most cost-effective mix of vehicles for reducing CO2 emissions and to estimate the subsidy that is necessary to achieve this vehicle mix. For this analysis, the energy system of Japan from 1988 to 2032 is modeled using a MARKAL model. The most cost-effective mix of vehicles is estimated by minimizing the total energy system cost under the constraint of an 8% energy-related CO2 emissions reduction nationally by 2030 from the CO2 emissions of 1990. Based on the results of the analysis, hybrid vehicles are the only type of clean-energy vehicle, and their share of the passenger car sector in 2030 will be 62%. By assuming the subsidization of hybrid vehicles, the same vehicle mix can be achieved without constraining CO2 emissions. The peak of the total subsidy estimated to be necessary is 1.225 billion US$/year in 2020, but the annual revenue of the assumed 31 US$/t-C carbon tax from the passenger car sector is sufficient to finance the estimated subsidy. This suggests that we should support the dissemination of hybrid vehicles through subsidization based on carbon tax. [Copyright &y& Elsevier]

In order to attain the 2010 target of reducing, nationally, greenhouse gases by 6% to the 1990 level, with reference to the Kyoto Protocol, the Government of Japan has planned and implemented some measures. This paper discusses the possible impacts of these measures on the nitrogen-oxide and sulfur-dioxide emissions from manufacturing industries in Hiroshima Prefecture. Trends of emission from twenty-three types of manufacturing industries in Hiroshima Prefecture, the calculations based on fuel consumption, are presented for 20 years (1990–2010). Three scenarios were developed, related to the possible achievement of particular measures together with Nippon Keidanren (Japan Business Federation) voluntary action plan on the environment. Predictions show that nitrogen-oxide and sulfur-dioxide emissions may be decreased from 18.9 and 21.5 kton in 1990 to 15.1 and 14.2 kton in 2010, respectively if Japanese energy policy and targets in voluntary action plans are successfully implemented. If they are less successfully implemented, the annual sulfur-dioxide emission could decrease to 17.9 kton and nitrogen-oxide emission will be same with 1990s level. [Copyright &y& Elsevier]