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Reactive volatile organic compounds (VOCs) are known to affect atmospheric chemistry, especially biogenic VOCs (BVOCs) which have a significant impact on regional air quality due to their large emission rates and high reactivities. Diterpenes (Kaur-16-ene and a diterpene likely to be Hibaene) were detected in all of the 205 enclosure air samples collected over multiple seasons at two different sites from Cryptomeria japonica and Chamaecyparis obtusa trees, the dominant coniferous trees in Japan. The emission rate of Kaur-16-ene, was determined to be from 0.01 to 7.1 µg dwg-1 h-1 (average: 0.61 µg dwg-1 h-1) by branch enclosure measurements and solid phase -- liquid extraction techniques. The emission rate was an order of magnitude higher than that of monoterpenes which are known to comprise a major portion of total BVOC emissions. In addition, total emission of Kaur-16-ene at 30 °C was estimated to be comparable to that of total anthropogenic VOC emissions. To our knowledge, this is the first report of volatile diterpene emissions from trees. [ABSTRACT FROM AUTHOR]

Due to its long-term negative health effects and increasing emissions, the PM2.5 issue has caused rising concerns in recent years. Although official media from East Asian countries tend to avoid blaming PM emission sources on their neighboring countries, researches have proved the existence of pronounced long-range trans-boundary particulate matters transported by nature force and by human activities. In this context, this paper included the structural path analysis (SPA) to quantify trans-boundary PM2.5 at sector level, track its transaction paths and figure out the linkages between consumption and production responsibilities of China, Japan and Korea. Based on the results and policy reviews of current environmental cooperation mechanisms, this paper found that: Considering the China-Japan and China-Korea trades, China's net exportation of embodied PM2.5 emissions has exceeded the importation rates over 10 times (CHN → JPN, 56.53 kt, JPN → CHN, 3.58 kt; CHN → KOR, 59.19 kt, KOR → CHN, 5.31 kt). Japan and Korea benefited from importing raw materials with high emission intensity from China to meet domestic consumption needs and keep a low national emission level. China, the largest emitter in the world, should first take the responsibility to mitigate its huge domestic PM2.5 emission. However, the relocated emissions from its neighboring countries should not be ignored. For Japan or Korea, due to the close economic interdependence and geographical position, any contribution to the reduction of the trans-boundary emissions or to the solution of atmosphere problems within China also helps those countries themselves. In the long run, all three countries would benefit from enhancing subregional environmental cooperation. [ABSTRACT FROM AUTHOR]

This study tries to find new insights of implementations of carbon tax policy as a suitable way to reach the long-term zero-carbon plan. This paper explores how carbon tax can affect the macroeconomy in Japan through the structural vector autoregression (S-VAR) technique conducted for the quarterly data throughout 2005–2020. A theoretical general equilibrium model backs the empirical analysis. The major findings reveal that any increase in energy price from the carbon tax will lead to an increase in interest rate, exchange rate, and consumer price index while there is a negative relationship between energy price increase from carbon tax and real gross domestic product (GDP) in Japan. Carbon Policy Refolution (Reform + Evolution), refunding carbon tax revenues, and adaptation of long-term policy of net zero GHG emissions by 2050 with the current situation of Japan's power sectors are the major practical policies of this study. [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]

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]

The Triad—North America, Japan and Europe—now addresses diesel vehicle emissions by requiring 40–80% reductions from new heavy-duty trucks and passenger car diesels. The requirements imply introduction of new technology and fuels stepwise during 2005–2012 that will leave emissions from new diesel vehicles on par with the levels of gasoline passenger cars. This paper studies the recent development of diesel engine emission control in response to new regulation. The role for Swedish actors, including two of the world’s major truck manufacturers, is especially studied. The increasingly global Technological System for diesel engine emission control is compelled to manage further reductions of nitrogen oxides emissions and fuel consumption and CO2, the balance of which has been the subject of several large legal disputes. Swedish OEMs are at present split into two technological sub-trajectories, while the future may be multi-pronged and include new engine types and fuels. Interestingly, similar commercial advantages that were sought by the pioneers introducing advanced feedback loop catalysis in gasoline cars in the 1970s are now sought by some heavy-duty diesel engine manufacturers by conversely avoiding the mainstream—Selective catalytic reduction—solution. Incremental innovation is the new radical. [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]

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]

Cities worldwide have introduced or revived light rail transit (LRT) to develop compact city strategies and help address environmental issues, such as increasing CO2 emissions or air pollution. Toyama is such a city that has addressed these issues by establishing a compact city rooted in transportation policies, notably the LRT established in 2006. Although there appears to be a consensus that the LRT contributes to establishing a compact city, contributing factors to ridership remain unclear. This study attempts to identify these factors, using the norm-activation model and theory of planned behaviour as a theoretical grounding, questionnaires for a data collection method and structural equation modelling for data analysis. The findings suggest that attitudes, perceived behavioural control and behavioural norms are significantly associated with the intention to use the LRT, which is, along with age, associated with its actual use. Based on these findings, this study provides theoretical and practical insights for cities wanting to pursue establishing or developing an LRT system. [ABSTRACT FROM AUTHOR]

In Japan, the achievement rate of environmental standards for air pollution has been improving in recent years, but for photochemical oxidants, including ozone, improvement are required. In this study, we investigated trends in ozone countermeasures in the United States and Europe from the State Implementation Plan (SIP) and National Air Pollution Control Program (NAPCP) and examined whether there are any points recommended in Japan. The United States and Europe have different policies on environmental standards for air pollution and ozone control. In the United States, states that do not meet the environmental standards for ozone concentration are required to develop an SIP to attain the standards. There was an urgent need to find a cost-effective approach to addressing the ozone problem, and forest control measures were one of the possibilities. In Europe, the European Union has set "target values" for ozone and NAPCP does not mention forest control measures or ozone sensitivity regimes. The main focus in Europe is on the win-win solution of reducing emissions of air pollutants at the same time as greenhouse gases. Japan should consider a framework including setting feasible step-by-step goals to attain the desired standards. As ozone is greatly affected by advection, wide-regional measures against ozone precursors and prediction of the future precursor reduction and concentration are required. The preparation of an emissions inventory and estimated reduction amount is prerequisites as basic data for simulation. To achieve this, cooperation between national, local and private research institutes is crucial. Since the international community has agreed to prioritize greenhouse gas countermeasures, Japan could consider a win-win solution for both ozone and greenhouse gas reduction. [ABSTRACT FROM AUTHOR]

The world's forest area decreased to three point nine billion hectares in 2015, a net annual loss of 3.3 million hectares, and large-scale deforestation is occurring in the tropics. Furthermore, greenhouse gas emissions are increasing as forests are converted to other uses such as agricultural land. Against this backdrop, sustainable forest management is becoming increasingly important. This study attempts to quantify people's general awareness and values concerning for on-line shopping habits (in this study, for wooden furniture) in terms of sustainable forest management in Japan by estimating the acceptable price premium or willingness of consumers to pay for wood-related products made using wood produced under sustainable forest management as the raw material. The study proceeds to quantify the awareness and values of consumers concerning sustainable forest management and conservation of forest environments. Consumers were found to have a certain willingness to pay for wooden furniture made from wood produced through sustainable forest management. As a consequence of this analysis, it was revealed that consumers place a high value on sustainable forest management and environmental conservation, and that they are willing to act on these values when purchasing wood-related products. [ABSTRACT FROM AUTHOR]

Many information and communications technology (ICT) services have become commonplace worldwide and are certain to continue to spread faster than before, particularly along with the commercialization of 5G and movement restrictions in response to the COVID-19 Pandemic. Although there is a concern that ICT equipment usage may increase power consumption and emit greenhouse gas (GHG) emissions, ICT has also been contributing to reducing GHG emissions through improved productivity and reduced mobility. This research targeted the main ICT services used in Japan and adopted a dynamic national computable general equilibrium model to quantitatively analyze future impacts on economic growth and GHG emission reduction until 2030 by using these ICTs, while considering both the increase in power consumption of ICT itself and the reduction in environmental load in other sectors. The results showed that the spread of ICT services, especially some artificial intelligence-based services, can improve productivity in most sectors through labor-saving and contribute to improving overall gross domestic product (GDP). Additionally, increased efficiency of logistics and manufacturing can greatly reduce the input of oil and coal products and so greatly contribute to GHG emission reduction. In 2030, compared with the baseline scenario in which all technology levels are fixed at current levels, at least 1% additional GDP growth and 4% GHG emission reduction can be expected by the targeted introduction of ICT in the ICT accelerated scenario in which the technology level of ICT accelerates. This also means ICT can potentially decouple the economy from the environment. [ABSTRACT FROM AUTHOR]

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: 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]

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]

Oceanic absorption of heat generated by greenhouse gas emissions has resulted in warming of the dark ocean (>200 m) that contains a large refractory DOM (RDOM) pool. However, changes in microbially mediated production and degradation dynamics for RDOM components in response to warming of dark marginal basins remain unclear. Herein, we integrated data from the dark South China, Mediterranean and Japan Seas (temperature range: 0.09–15.1°C) to demonstrate that in situ production efficiency of two ubiquitous humic‐like fluorophores increased at higher dark ocean temperature, whereas chromophores at a wavelength of 325 nm (aCDOM(325)) changed from production to degradation at higher temperature. Increased oxygen consumption and a reduction of labile substrates in future warmer dark ocean environments may initiate the final degradation of some semi‐refractory components, thereby increasing the recalcitrance of RDOM, but decreasing the DOM inventory in dark basins and creating a positive feedback to rising atmospheric CO2. Plain Language Summary: Marine refractory dissolved organic matter (RDOM) in the dark ocean is primarily formed during heterotrophic degradation of labile organic matter, which has a pronounced sensitivity to temperature variation. Since the 1960s, the global dark ocean has exhibited an accelerated warming with a discernable temperature increase. Thus, determining the importance of temperature on microbial regulation of the oceanic RDOM pool is of great significance. This study utilized the ocean interior of the marginal South China, Mediterranean and Japan Seas as natural basin‐scale enclosed incubators along with optical DOM characterization methods to reveal a production‐degradation reaction series for RDOM components. A decrease in the DOM inventory by enhanced microbial mineralization (producing CO2) in a warmer dark ocean may create a positive feedback in response to global climate change. Key Points: Faster turnover for optical components of dissolved organic matter (DOM) was observed in dark marginal basins than in the open oceanIn situ production efficiency of two ubiquitous humic‐like fluorophores increased at higher dark ocean temperaturesAn increase of DOM recalcitrance and decrease of the bulk dissolved organic carbon pool may occur due to a future warming of dark basins [ABSTRACT FROM AUTHOR]

This study developed a database of emission inventories from ships around Japan using the activity data in the 2015 Japanese fiscal year. The emission of air pollutants from ships was estimated for fuel combustion in main engine, auxiliary engines, and boilers onboard. The ships’ operations for the emission estimation in the exhaust gas consist of ships in navigation, ships at anchor, and fishing boats. For the emission estimation regarding navigation ships, data from Automatic Identification System (AIS) received at the stationary stations on land in Japan were used in this study to calculate the activity. The emission amounts were compared between the sea (Seto Inland Sea (SIS) and Tokyo Bay) and prefectures surrounding those ocean areas. The ship emission ratios in total anthropogenic emissions including the land part reached SO2: 29%, PM: 40%, and NOx: 22% for the SIS area. In Tokyo Bay, the ship emission ratios in total reached SO2: 36%, PM: 28%, and NOx: 13%, and the emission intensities per unit area for SO2 and PM2.5 are approximately three times higher than those in the other regions, respectively. Therefore, the shipping traffic density is relatively higher compared to transportation on land, and the emission is condensed locally. Assuming that the 2020 global sulphur limit switched to a sulphur content of 0.50% m/m, SO2 emissions could be reduced to 24% in SIS and 22% in Tokyo Bay, sulphate emissions could be reduced to 23% in SIS and 21% in Tokyo Bay, and PM emissions could be reduced to 39% in SIS and 36% in Tokyo Bay. Therefore, the 2020 global sulphur limit should reduce the emission from ships around the Japan coastal area and improve the air quality in congested water areas such as SIS and Tokyo Bay. [ABSTRACT FROM AUTHOR]

Numerous studies have reported that ambient air pollution, which has both local and long-range sources, causes adverse impacts on the environment and human health. Previous studies have investigated the impacts of transboundary air pollution (TAP) in East Asia, albeit primarily through analyses of episodic events. In addition, it is useful to better understand the spatiotemporal variations in TAP and the resultant impact on the environment and human health. This study aimed at assessing and quantifying the air quality impacts in Japan and South Korea due to local emissions and TAP from sources in East Asia - one of the most polluted regions in the world. We applied state-of-the-science atmospheric models to simulate air quality in East Asia and then analyzed the air quality and acid deposition impacts of both local emissions and TAP sources in Japan and South Korea. Our results show that ∼ 30 % of the annual average ambient PM 2.5 concentrations in Japan and South Korea in 2010 were contributed to by local emissions within each country, while the remaining ∼ 70 % were contributed to by TAP from other countries in the region. More detailed analyses also revealed that the local contribution was higher in the metropolises of Japan (∼ 40 %–79 %) and South Korea (∼ 31 %–55 %) and that minimal seasonal variations in surface PM 2.5 occurred in Japan, whereas there was a relatively large variation in South Korea in the winter. Further, among all five studied anthropogenic emission sectors of China, the industrial sector represented the greatest contributor to annual surface PM 2.5 concentrations in Japan and South Korea, followed by the residential and power generation sectors. Results also show that TAP's impact on acid deposition (SO42- and NO3-) was larger than TAP's impact on PM 2.5 concentrations (accounting for over 80 % of the total deposition), and that seasonal variations in acid deposition were similar for both Japan and South Korea (i.e., higher in both the winter and summer). Finally, wet deposition had a greater impact on mixed forests in Japan and savannas in South Korea. Given these significant impacts of TAP in the region, it is paramount that cross-national efforts should be taken to mitigate air pollution problems across East Asia. [ABSTRACT FROM AUTHOR]

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Air pollution trends in Japan between 1970 and 2012 were analyzed, and the impact of air pollution counter-measures was evaluated. Concentrations of CO decreased from 1970 to 2012, and in 2012, the Japanese environmental quality standard (EQS) for CO was satisfied. Concentrations of SO2 dropped markedly in the 1970s, owing to use of desulfurization technologies and low-sulfur heavy oil. Major reductions in the sulfur content of diesel fuel in the 1990s resulted in further decreases of SO2 levels. In 2012, the EQS for SO2 was satisfied at most air quality monitoring stations. Concentrations of NO2 decreased from 1970 to 1985, but increased from 1985 to 1995. After 1995, NO2 concentrations decreased, especially after 2006. In 2012, the EQS for NO2 was satisfied at most air quality monitoring stations, except those alongside roads. The annual mean for the daily maximum concentrations of photochemical oxidants (OX) increased from 1980 to 2010, but after 2006, the 98th percentile values of the OX concentrations decreased. In 2012, the EQS for OX was not satisfied at most air quality monitoring stations. Non-methane hydrocarbon (NMHC) concentrations generally decreased from 1976 to 2012. In 2011, NMHC concentrations near roads and in the general environment were nearly the same. The concentration of suspended particulate matter (SPM) generally decreased. In 2011, the EQS for SPM was satisfied at 69.2% of ambient air monitoring stations, and 72.9% of roadside air-monitoring stations. Impacts from mineral dust from continental Asia were especially pronounced in the western part of Japan in spring, and year-round variation was large. The concentration of PM2.5 generally decreased, but the EQS for PM2.5 is still not satisfied. The air pollution trends were closely synchronized with promulgation of regulations designed to limit pollutant emissions. Trans-boundary OX and PM2.5 has become a big issue which contains global warming chemical species such as ozone and black carbon (so called SLCP: Short Lived Climate Pollutants). Co-beneficial reduction approach for these pollutants will be important to improve both in regional and global atmospheric environmental conditions. [ABSTRACT FROM AUTHOR]

Building sector is the highest growing sector in energy demand in Japan at present. There is a strong need to reduce this sectoral energy demand to achieve the national carbon emission target. This study focuses on Japanese commercial sector and shows model analysis results of energy efficiency policy impacts on the sectoral carbon emission trajectory, using CRIEPI's bottom-up energy model. The policy cases we analyzed are consistent with those of other EMF25 model teams. The results indicate that, the introduction of low carbon tax has little impact on the sectoral final energy demand and carbon emission trajectory and, on the other hand, enhanced energy efficiency standard and reduced equipment cost of products are very effective on reducing the sectoral energy demand. [ABSTRACT FROM AUTHOR]

Systematic changes of the ozone weekend effect are found over broad areas of Japan. These changes are characterized by (1) spatial reversals from a weekend increase in the vicinity of huge precursor source areas to a weekend decrease in the surrounding rural areas, and (2) temporal reversals from a weekend increase under relatively unsuitable meteorological conditions for ozone formation to a weekend decrease under relatively suitable conditions. We developed a simple numerical advection-reaction model to explain the relationship between the duration of advection and the supplied solar energy, which causes the daily maximum ozone concentration to be lower near the precursor source. Ozone isopleth diagrams for individual advection durations (equivalent to the distance from the source) for a wide range of initial precursor conditions show that both VOC-limited and NOx-limited regimes exist for each advection duration, but the area of NOx-limited regime becomes dominant as the advection duration increases because of the increased exposure of the air mass to solar energy. For given initial VOC and NOx concentrations, the area remote from the source becomes a NOx-limited regime even if the precursor source area is in the VOC-limited regime. The rate of reduction of weekend emissions of NOx is larger than that of VOC, causing a weekend increase in ozone inside an area of VOClimited regime near the source, but a weekend decrease in remote areas with a NOx-limited regime. The boundary between these two ozone formation regimes depends on meteorological conditions: when sunlight intensity and temperature are relatively low, the change from a VOC-limited to a NOx-limited regime occurs at a point more remote from the source than when they are relatively high, which causes a prevailing ozone weekend increase over a wide geographical area on days with lower ozone potential. Therefore, observations of ozone weekend changes can be interpreted in light of the theoretical implications of our model; they can be used for determination of ozone formation regimes, which change in different locations and under different meteorological conditions. [ABSTRACT FROM AUTHOR]

In-situ observations of atmospheric CO2 and CH4 at Hateruma Island (24.05σ N, 123.80σ E, 47m a.s.l), Japan shows large synoptic scale variations during a 6-month period from November to April, when the sampled air is predominantly of continental origin due to the Asian winter monsoon. Synoptic scale variations are extracted from the daily averaged values for the years between 1996 and 2007, along with the annual standard deviations (σCO2 and σCH4 for CO2 and CH4, respectively) for the relevant 6-month period. During this 6-month period the absolute mixing ratios of CO2 and CH4 at Hateruma are also elevated compared to those at two sites in the central North Pacific Ocean. The temporal change in σCO2 shows a systematic increase over the 12-year period, with elevated excursions in 1998 and 2003; there is no clear increase in σCH4 . We also find that the σCO2 /σCH4 ratio increases gradually from 1996 to 2002 and rapidly after 2002 without any extreme deviations that characterised σCO2 . The σCO2 /σCH4 ratio correlates closely with the recent rapid increase in fossil carbon emissions from China, as indicated in the Carbon Dioxide Information Analysis Center (CDIAC) database. This methodology can be applied to multiple chemical tracers of sufficient lifetime, for tracking overall changes in regional emissions. [ABSTRACT FROM AUTHOR]

We investigated the influence of meteorological variability on the interannual variation of springtime boundary layer ozone over Japan during 1981-2005 by multiyear simulations with the Models-3 Community Multiscale Air Quality (CMAQ) modeling system and the Regional Emission Inventory in Asia (REAS). CMAQ/REAS generally reproduced the observed interannual variability of springtime ozone over Japan, showing year-to-year variations larger than the annual rate of increase of the long-term trend. We then analyzed the influence of the interannual variation of meteorology in simulated results by using the fixed emissions for 2000 and meteorological fields for each year. As a reference parameter, we calculated the area-weighted surface pressure anomaly over the Pacific Ocean east of Japan. When the anomaly has a large negative value, polluted air masses from continental Asia tend to be transported directly to Japan by westerly winds. In contrast, when the anomaly has a large positive value, influence of the outflow from continental Asia tends to be small because the westerly components of wind fields around Japan are comparatively weak. Instead, southerly winds are relatively strong and transport clean air masses from the Pacific Ocean to Japan. Consequently, springtime ozone over Japan is higher (lower) than in ordinary years when the anomaly has a large negative (positive) value. In general, the interannual variation of springtime ozone over Japan is sensitive to the outflow from continental Asia. We also found some correlation between springtime ozone over Japan and the El Niño-Southern Oscillation, indicating that higher and lower springtime ozone over Japan are related to La Niña and El Niño, respectively. Differences in the meridional displacement and diversity of cyclone tracks near Japan between El Niño and La Niña years may be responsible for interannual variations in the springtime boundary layer ozone over Japan. [ABSTRACT FROM AUTHOR]

Atmospheric N2O concentration was observed in the Pacific for the period 1991–2006, using commercial container ships sailing between Japan and North America and between Japan and Australia or New Zealand. The N2O concentration showed a secular increase and interannual variations at all sampling locations, but a seasonal cycle was detectable only at northern high latitudes. The annual mean N2O concentration showed little longitudinal variations (within ± 0.3 ppb) in the northern Pacific, but showed a clear north-south gradient of about 0.8 ppb, with higher values in the Northern Hemisphere. The annual mean N2O was also characterized by especially high values at 30°N due to strong local N2O emissions and by a steep latitudinal decrease from the equator to 20°S due to the suppression of interhemispheric exchange of air by the South Pacific Convergence Zone. The N2O growth rate showed an interannual variation with a period of about 3 yr (high-values in 1999 and 2000), with a delayed eastward and poleward phase propagation in the northern and western Pacific, respectively. The interannual variations of the N2O growth rate and soil water showed a good correlation, suggesting that the N2O emission from soils have an important causative role in the atmospheric N2O variation. [ABSTRACT FROM AUTHOR]

The role of forests in absorbing atmospheric carbon has been recognized under the Kyoto Protocol, which allows signatory countries to use forests as a mitigation option. Although several studies have estimated carbon stock changes in Japanese forests, most only estimate changes up to 1995 or ignore carbon stock changes in natural forests. This study is the first attempt to estimate carbon stock changes in Japanese forests from 1966 to 2012, to coincide with the final year of the Kyoto Protocol's first commitment period. Forest area and growing stock data were analysed. Then, two models for predicting the change in forest area and growing stock were developed. Results showed that most natural forest loss resulted from conversion to plantation forest. The total above-ground and below-ground carbon stock in Japanese forests has been estimated to have increased from 1114.8 TgC in 1966 to 2076.0 TgC in 2012, representing an increase of 20.9 TgC year-1 over the same period. During the first commitment period of the Kyoto Protocol (2008-2012), annual carbon sinks were estimated at 20.1 TgC, of which ~76.9 per cent were sequestered in plantation forests. Of the 20.1 TgC year-1, eligible carbon sinks are estimated at 10.2 TgC or ~78.7 per cent of the maximum or capped amount as allowed under the Marrakesh Accord. Although further effort is needed so that the capped amount of 13 TgC year-1 could be achieved, this study suggests that carbon sinks through forest management could be used to offset industrial carbon emissions. [ABSTRACT FROM AUTHOR]

Young lignite from two locations in Sendai City, Japan, were analyzed for polynuclear aromatic compounds (PACs). Lignite samples were extracted with toluene and PACs were isolated by a compound-class-selective, reactive matrix clean-up. This clean-up separates all compounds of polynuclear aromatic structure, for example hydrocarbons and ketones and their primary metabolites, from interfering organic compounds. The result of this isolation procedure is, therefore, a group of a large number of polycyclic compounds with different functional groups. Further analysis is done by glass capillary gas chromatography. Perylene was identified as the only compound obtained by the reactive matrix clean-up of lignite samples from both locations. Concentrations were in the range of 1–10 mg kg−1. Conversely, PACs resulting from particulate emissions from fossil fuel combustion always contain isomeric PAHs (polynuclear aromatic hydrocarbons) with some polycyclic aromatic ketones and thousands of primary and secondary metabolites at very low concentrations. This was demonstrated for a sample of urban air particulate matter, which is the source of PAC contamination of surface soil. The absence of accompanying PAHs and polynuclear aromatic ketones in the lignite samples confirms that perylene did not originate from a combustion process. It is assumed that the high concentrations of perylene are the result of a reduction of perylene quinone. Thus, the high perylene content of the lignite samples investigated is of biogenic origin. [ABSTRACT FROM AUTHOR]

Weak early compliance with the Kyoto Protocol's current emissions reduction targets and the longer term impact of the US's defection point to emerging problems for the Protocol's effectiveness and legitimacy. This article argues that such problems could in part be addressed by shifting the emphasis of negotiations over the Protocol's second commitment period away from attempts to reengage the United States. Instead, these negotiations and key actors like the European Union should aim for a framework and 'culture of compliance' that actively engage the 'emergent major emitters', China, India and Brazil, either by including them in the Protocol's Annex B list of states, or in a new annex created specially to accommodate them. [ABSTRACT FROM AUTHOR]

The creep trend method is used for the analysis of the development of electric car production in three regions: The United States, the European Union and Japan. Based on vehicle registration and population growth data for each year the creep trend method using historical data for the years 2007–2017 is applied for forecasting development up to 2030. Moreover, the original method for calculating the primary energy factor (PEF) was applied to the analysis of power engineering systems in the regions investigated. The assessment of the effects of electromobility development on air quality has been performed, reduction values for pollutant and greenhouse gas emissions have been determined, which was the main objective of this manuscript. Mitigation of air pollutant emissions, i.e., carbon dioxide (CO2), carbon monoxide (CO) and nitrogen oxides (NOx) was estimated and compared to the eventual expected increase of emissions from power plants due to an increase of the demand for electricity. It can be concluded that electricity powered cars along with appropriate choices of energetic resources as well as electricity distribution management will play the important role to achieve the sustainable energy economy. Based on the emission reduction projections resulting from the projected increase in the number of electric cars, (corrected) emissions will be avoided in 2030 in the amount of over 14,908,000 thousand tonnes CO2 in European Union, 3,786,000 thousand tonnes CO2 in United States and 111,683 thousand tonnes CO2 in Japan. [ABSTRACT FROM AUTHOR]