Revealing the intersectoral material flow of plastic containers and packaging in Japan.

The Japanese government developed a strategy for plastics and laid out ambitious targets including the reduction of 25% for single-use plastic waste and the reuse/recycling of 60% for plastic containers and packaging by 2030. However, the current usage situation of single-use plastics including containers and packaging, which should be a basis of the strategy, is unclear. Here, we identify the nationwide material flow of plastics in Japan based on input-output tables. Of the domestic plastic demand of 8.4 Mt in 2015, 1.6 and 2.5 Mt were estimated to be for containers and packaging comprising household and industry inflows, respectively, through the purchase/procurement of products, services, and raw materials. Considering the current amount of recycling collected from households (1.0 Mt) and industries (0.3 to 0.4 Mt), the reuse/recycling target has already been achieved if the goal is limited to household container and packaging waste, as is the focus of Japan's recycling law. Conversely, the results indicate that it will be extremely difficult to reach the target collectively with industries. Therefore, it is essential that efforts be made throughout the entire supply chain. Food containers and packaging that flowed into the food-processing and food service sectors accounted for 15% of the inflow of containers and packaging into industries. Thus, the key to achieving the reuse/recycling target will comprise the collection of plastic food packaging from not only households but also the food industry. Furthermore, the collection of flexible plastic films used between industry sectors will put the target within reach.

Exploring China's materialization process with economic transition: analysis of raw material consumption and its socioeconomic drivers.

China's rapidly growing economy is accelerating its materialization process and thereby creating serious environmental problems at both local and global levels. Understanding the key drivers behind China's mass consumption of raw materials is thus crucial for developing sustainable resource management and providing valuable insights into how other emerging economies may be aiming to accomplish a low resource-dependent future. Our results show that China's raw material consumption (RMC) rose dramatically from 11.9 billion tons in 1997 to 20.4 billion tons in 2007, at an average annual growth rate at 5.5%. In particular, nonferrous metal minerals and iron ores increased at the highest rate, while nonmetallic minerals showed the greatest proportion (over 60%). We find that China's accelerating materialization process is closely related to its levels of urbanization and industrialization, notably demand for raw materials in the construction, services, and heavy manufacturing sectors. The growing domestic final demand level is the strongest contributor of China's growth in RMC, whereas changes in final demand composition are the largest contributors to reducing it. However, the expected offsetting effect from changes in production pattern and production-related technology level, which should be the focus of future dematerialization in China, could not be found.

Time-series variations in 129I concentrations and 129I/137Cs ratios in suspended particulate matter collected in eastern Japan immediately after the 2011 nuclear accident in Fukushima, Japan.

We have determined the hourly atmospheric concentrations of 129I in aerosols dispersed into the atmosphere by the nuclear accident at the Fukushima Daiichi Nuclear Power Plant (FD1NPP) on March 11, 2011. Data were obtained by measuring the quantity of 129I in suspended particulate matter (SPM) collected on filter tapes at 41 SPM monitoring stations in Fukushima and other prefectures in eastern Japan, including the metropolitan area of Tokyo and the surrounding area. After scrutiny, 500 out of 920 hourly SPM samples were determined to be reliable (i.e., devoid of cross-contamination), and these were subjected to further analysis and discussion. Based on the data from these samples, especially data from the four SPM sampling sites located close to the FD1NPP (Futaba, Naraha, Haramachi and Nihonmatsu), the time-series variations in the atmospheric concentration of 129I and the activity ratio of 129I/137Cs were reconstructed by using 137Cs concentration data in the literature. 129I and 137Cs were observed to be continuously and sometimes explosively dispersed into the atmosphere in aerosols transported by radioactive plumes from the FD1NPP. The highest activity concentrations of 129I and 137Cs were observed in the SPM sample at the Futaba SPM station (3.2 km west-northwest of the FD1NPP) at 14:00-15:00 on March 12 after the venting of Unit 1. Systematically high 129I/137Cs activity ratios were observed at the Futaba and Haramachi stations from March 12 to 14, suggesting that radioactive masses released from the FD1NPP during the first few days after the nuclear accident were relatively enriched in radioiodine. High activity ratios of 129I/137Cs were also measured starting on March 21 at Naraha (17.5 km south of FD1NPP) and from March 22-23 in the metropolitan area which must have been caused by a different type of emission event(s) on those days at the FD1NPP, as previously reported. The 129I data from this study are highly effective in the validation and elaboration of the modelling of the atmospheric dispersion of radioiodine. They further contribute to assessing the internal exposure due to inhalation of 131I estimated by means of such elaborate atmospheric diffusion models.

Data on atmospheric 129I concentrations and 129I/137Cs ratios for suspended air particulate matter dispersed in eastern Japan just after the 2011 nuclear accident in Fukushima, Japan.

Data of the atmospheric activity concentrations (in Bq/m3) of 129I dispersed into the environment as aerosol immediately after the nuclear accident at Fukushima Daiichi Nuclear Power Plant in 2011 are presented. The radioactivity of 129I was determined in suspended particulate matter (SPM) collected on filter tapes at 41 SPM monitoring sites in Fukushima and other prefectures in eastern Japan including the metropolitan area. For quantitative determination of 129I in SPM samples by accelerator mass spectrometry (AMS), 129I was chemically separated. Prior to the 129I measurement, the 137Cs activity was determined for the same SPM sample by gamma-ray spectrometry using Ge-semiconductor detectors. Combining activity concentrations of the two nuclides, an activity ratio of 129I/137Cs (in Bq/Bq) was calculated for each SPM sample. In our research project, atmospheric activity concentrations of 129I and 137Cs, and their activity ratios were obtained for 920 SPM samples. Scientific discussion related to those data was described in the research article entitled "Time-series variations of atmospheric 129I concentrations and 129I/137Cs ratios in eastern Japan just after the 2011 nuclear accident in Fukushima, Japan" (Ebihara et al. 2022), where 363 data sets were presented. The remaining 557 data sets are presented in this article, so this data article makes up for the original research article (Ebihara et al. 2022). Blank values were obtained for whole analytical procedure. In addition, those for reagents and filters (both bland-new and used filters) were analyzed for assessing the contribution of the 129I activity from these samples. Those data also are presented in this article.

Reassessment of early 131I inhalation doses by the Fukushima nuclear accident based on atmospheric 137Cs and 131I/137Cs observation data and multi-ensemble of atmospheric transport and deposition models.

The Fukushima Dai-ichi Nuclear Power Plant accidents following the March 11, 2011 Tohoku earthquake, and subsequent tsunami released radioactive materials into the atmosphere and caused significant public health concerns, particularly thyroid cancers in children. However, the lack of measurement data for atmospheric concentrations of 131I has caused persistent and widespread uncertainty. This study estimated the maximum potential thyroid doses of inhaled 131I in the early post-accident phase between March 12 and 23, 2011 by using the hourly measured data of the 137Cs concentrations at 101 suspended particulate matter (SPM) monitoring sites, a new multi-model ensemble (MME) method of simulating 137Cs concentrations using two Atmospheric Transport and Deposition Models (ATDMs), the 131I/137Cs ratio obtained from measurement data analysis, and the internal exposure model. Based on the measurements, the maximum potential thyroid doses were estimated at 3.1-160 mSv at 5 sites in the Fukushima-Hamadori area for 1-year-old children assumed to remain outdoors, whereas they were less than 4.3 mSv at the other sites in the base case of the 131I/137Cs ratio. The spatial distribution of the maximum potential of early inhalation doses was estimated by using the MME and measurements. The inhalation thyroid doses in the evacuation scenarios were compared to the estimates reported by previous studies. The results of the present study were almost congruent with the outcomes of previous investigations except for thyroid doses contributed by highly contaminated plumes on March 12 and 15. The sensitivity analysis for the 131I/137Cs ratio indicated that these plumes carried the potential to significantly increase the thyroid doses of residents.

Dynamics of atmospheric 131I in radioactive plumes in eastern Japan immediately after the Fukushima accident by analysing published data.

The spatio-temporal distribution of atmospheric radioiodine immediately after the Fukushima Daiichi Nuclear Power Plant (FD1NPP) accident has not yet been clarified due to very limited observed data, compared with atmospheric radiocaesium data. Here, we first revealed that the ratios of 131I (decay-corrected to March 11, 2011) to 137Cs in radioactive plumes were divided into three groups (A, B, and C) by analysing all published data on atmospheric 131I concentrations independently measured immediately after the accident in eastern Japan. Groups A and C were found regardless of whether the measurement sites were located in eastern Fukushima or Kantou areas, while group B was observed only in the eastern Kantou area. The ratios in group A were approximately equal to 10 for the plumes on March 15, March 20, and on the morning of March 21, and those in group B were approximately 75 on March 16. Their possible sources were Unit 2 and/or Unit 3. In contrast, the ratios in group C were approximately equal to 360, much higher than those of groups A and B, and were observed from the afternoon of March 21 to March 25. These high 131I concentrations could be released after water supply to FD1NPP.

A new approach for reconstructing the 131I-spreading due to the 2011 Fukushima nuclear accident by means of measuring 129I in airborne particulate matter.

To retrieve the diffusion trajectory of the 131I dispersed in the environment by the nuclear power plant accident in Fukushima in 2011, airborne particulate matter (APM) samples collected in the Tokyo metropolitan area were analyzed for their 129I contents by means of accelerator mass spectrometry. In evaluating blank levels of chemicals and filters used for collecting APM, we established the analytical procedure for determining the 129I activity of as low as 10-8 Bq for a small piece of filter samples (about 0.1 cm2). Coupled with 131I data determined just after the accident, activity ratios of 129I/131I were obtained with a mean value of 2.29 × 10-8 (±28% of a standard deviation). This value is systematically smaller than a mean value of soil samples by 16-24% and the inventory data by 27%, suggesting that 129I was partly lost from APM. As 129I can be a proxy of 131I for APM, it is possible to trace how 131I in the particulate phase spread in eastern Japan and, furthermore, evaluate the internal radiation exposure due to 131I by inhalation of 131I-containing airborne particulates.

Where will large amounts of materials accumulated within the economy go?--A material flow analysis of construction minerals for Japan.

For all countries analyzed so far, Material Flow Analysis/Accounting (MFA) studies indicate that the overall stock of materials within the economy is growing. Most are construction minerals such as asphalt, cement, sand and gravel, crushed stone, and other aggregates. In the analyses described in this paper, flows and stocks of construction minerals were estimated for Japan from the past to the future to elucidate: (1) the mechanisms by which construction minerals become waste, and (2) the future supply of and demand for recycled crushed stone. The following conclusions were drawn: (1) The amounts of waste construction minerals generated have been and will be at much lower levels than the domestic demand for construction minerals. These differences might indicate consistent growth of the stock of construction minerals, which will become waste in the future. However, certain amounts of materials that we account for as stock can be interpreted already in the environment as dead stock or dissipated waste; such materials can be called "missing stock" or "dissipated stock". Capturing that missing or dissipated stock is very important because it provides information that clarifies the environmental impacts and loss of resources that these materials cause; it allows estimation of appropriate future waste generation. (2) The amount of construction minerals that are recognized as waste was estimated to increase in the future. An imbalance in the supply of and demand for recycled crushed stone will likely occur in the near future if an expected decline in future road construction is considered.

Time-series product and substance flow analyses of end-of-life electrical and electronic equipment in China.

Given the amounts of end-of-life electrical and electronic equipment (EoL-EEE) being generated and their contents of both harmful and valuable materials, the EoL-EEE issue should be regarded not only as an emerging environmental problem but also as a resource management strategy in China. At present, in order to provide the basis for managing EoL-EEE at both product and substance levels in China, it is necessary to carry out a quantitative analysis on EoL-EEE and to determine how much of it will be generated and how much materials and substances it contains. In this study, the possession and obsolescence amounts of five types of household appliance (HA) including television (TV) sets and the amounts of substances contained in EoL TV sets were estimated using time-series product flow analysis (PFA) and substance flow analysis (SFA). The results of PFA indicated that the total possession amounts of those five types of HAs will exceed 3.1 billion units in 2030, which will be two times higher than those in 2010. In addition, it was estimated that cumulatively over 4.8-5.1 billion units of these five types of EoL HA would be obsoleted between 2010-2030. The results of SFA on TV sets indicated that the generated amounts of most of the less common metals and a part of common metals such as copper (Cu) would tend to decrease, whereas those of other common metals such as iron (Fe) as well as precious metals would tend to increase in EoL TV sets in 2015-2030. The results of this study provide a quantitative basis for helping decision makers develop strategic policies for the management of EoL-EEE considering both environmental and resource aspects. Moreover, a calculation scheme of obsolete HAs presented in this study can be applied to estimate other types of EoL durable good. Meanwhile, the frameworks of this study will help not only the policy decision makers in the Chinese government but also those in developing countries that are facing similar problems.

Framework for estimating potential wastes and secondary resources accumulated within an economy--a case study of construction minerals in Japan.

Material stocks in economic society are considered to represent a reserve for wastes and secondary resources. From the viewpoints of proper disposal and reutilization of stocked materials, accurate estimation of the amount of materials that will emerge as wastes or secondary resources in the future is important. We defined materials that have a high probability of emerging as wastes or secondary resources as "potential wastes and secondary resources" and estimated that amount for construction minerals in Japan as a case study. The following conclusions were drawn. (1) We classified materials that are input into economic society into four categories: potential wastes and secondary resources, potential dissipated materials, dissipatively used materials, and permanent structures. By clarifying the latter three non-potential wastes and secondary resources, we performed a more accurate assessment of the wastes and secondary resources that will emerge in the future. (2) The share of potential wastes and secondary resources was estimated to be about 30% of all construction minerals that have been input into and accumulated in Japanese economic society. (3) Information related to potential dissipated materials and dissipatively used materials will provide fundamental knowledge to support analyses of the environmental impacts and resource losses which these materials might generate.

Simple indicator to identify the environmental soundness of growth of consumption and technology: "eco-velocity of consumption".

Today's material welfare has been achieved at the expense of consumption of finite resources and generation of environmental burdens. Over the past few decades the volume of global consumption has grown dramatically, while at the same time technological advances have enabled products with greater efficiencies. These two directions of change, consumption growth and technological advance, are the foci of the present paper. Using quantitative measures for these two factors, we define a new indicator, "eco-velocity of consumption", analogous to velocity in physics. The indicator not only identifies the environmental soundness of consumption growth and technological advance but also indicates whether and to what extent our society is shifting toward sustainable consumption. This study demonstrates the practicability of the indicator through a case study in which we calculate the eco-velocities of Japanese household consumption in 2 years: 1995 and 2000. The rate of technological advance during the periods concerned is quantified in terms of the embodied carbon dioxide emission per yen of product. The results show that the current growth rate of Japanese household consumption is greater than the rate of technological advance to mitigate carbon dioxide emissions. The eco-velocities at the level of individual commodity groups are also examined, and the sources of changes in eco-velocity for each commodity are identified using structural decomposition analysis.

Site-dependent life-cycle analysis by the SAME approach: its concept usefulness, and application to the calculation of embodied impact intensity by means of an input-output analysis.

This paper describes a practical approach to site-dependent life-cycle analysis (SDLCA) that differentiates site-dependent environmental impacts from a system's processes by considering the geographical conditions of each process. This approach converts an environmental output into its impacts by using site-dependent characterization factors (SDCFs). This approach defines an area-the Spatial Area of iMpact Equivalency (SAME)-within the boundaries of the geographical system during site-dependent life-cycle inventory (SDLCI) analysis and calculates an environmental output from a process for the SAMEs. Each SAME represents a collection of geographical areas with internally homogeneous environmental impacts and can be mapped using a geographic information system. Preparing a SDLCI and SDCFs based on SAMEs facilitates the implementation of SDLCA by permitting the use of fewer regions during SDLCI. To demonstrate application of the SAME approach, an embodied impact intensity was formulated; it quantifies the impact directly and indirectly on the basis of the unit activity of a sector by means of input-output analysis with SDCFs. The validity of using SAMEs for SDLCA is demonstrated through two case studies: one studying suspended particulate matter, and one studying benzene. In both cases, the impact intensities are calculated using the SAME approach and the results are compared with those of site-generic LCI.

Compilation and application of Japanese inventories for energy consumption and air pollutant emissions using input-output tables.

Preparing emission inventories is essential to the assessment and management of our environment. In this study, Japanese air pollutant emissions, energy consumption, and CO2 emissions categorized by approximately 400 sectors (as classified by Japanese input-output tables in 1995) were estimated, and the contributions of each sector to the total amounts were analyzed. The air pollutants examined were nitrogen oxides (NOx), sulfur oxides (SOx), and suspended particulate matter (SPM). Consumptions of about 20 fossil fuels and five other fuels were estimated according to sector. Air pollutant emission factors for stationary sources were calculated from the results of a survey on air pollution prevention in Japan. Pollutant emissions from mobile sources were estimated taking into consideration vehicle types, traveling speeds, and distances. This work also counted energy supply and emissions from seven nonfossil fuel sources, including nonthermal electric power, and CO2 emissions from limestone (for example, during cement production). The total energy consumption in 1995 was concluded to be 18.3 EJ, and the annual total emissions of CO2, NOx, SOx, and SPM were, respectively, 343 Mt-C, 3.51 Mt, 1.87 Mt, and 0.32 Mt. An input-output analysis of the emission inventories was used to calculate the amounts of energy consumption and emissions induced in each sector by the economic final demand.

Size distribution and characterization of ultrafine particles in roadside atmosphere.

The number concentration and number size distributions of ultrafine particles were measured with a Scanning Mobility Particle Sizer (SMPS) at a roadside in early autumn and winter, and the results are discussed with regard to the contribution of traffic activity and meteorological conditions. The number concentration of the <50 nm fraction increased in the morning under calm wind conditions, and this increase corresponded with the increase in total traffic volume and nitric oxide. The increase in ultrafine particles was influenced not only by the increase in total traffic but also by the high contribution of diesel engine vehicles. The number concentration decreased around noon as the wind speed increased, although the total traffic and the number of diesel engine vehicles were at the same level as in the morning. The number size distribution in the morning was bimodal, with a first peak diameter of around 30 nm and a second of around 90 nm in both periods. The volatility of ultrafine particles was investigated using a thermal denuder operating at 250 degrees C. The first peak consisted mainly of volatile components, whereas the second one consisted of solid materials plus some volatile components. These results were consistent with the mass size distribution of elemental and organic carbon. The number size distribution with a peak diameter of around 30 nm was also observed in the afternoon at a suburban site; however, it was produced not by vehicle emissions directly but by photochemical reactions. Although a relatively high number concentration was also observed in the morning at the suburban site due to vehicle emission, the peak diameter ranged from 40 to 90 nm, which was larger than at the roadside.

Geo-referenced multimedia environmental fate model (G-CIEMS): model formulation and comparison to the generic model and monitoring approaches.

A spatially resolved and geo-referenced dynamic multimedia environmental fate model, G-CIEMS (Grid-Catchment Integrated Environmental Modeling System) was developed on a geographical information system (GIS). The case study for Japan based on the air grid cells of 5 x 5 km resolution and catchments with an average area of 9.3 km2, which corresponds to about 40,000 air grid cells and 38,000 river segments/catchment polygons, were performed for dioxins, benzene, 1,3-butadiene, and di-(2-ethyhexyl)phthalate. The averaged concentration of the model and monitoring output were within a factor of 2-3 for all the media. Outputs from G-CIEMS and the generic model were essentially comparable when identical parameters were employed, whereas the G-CIEMS model gave explicit information of distribution of chemicals in the environment. Exposure-weighted averaged concentrations (EWAC) in air were calculated to estimate the exposure ofthe population, based on the results of generic, G-CIEMS, and monitoring approaches. The G-CIEMS approach showed significantly better agreement with the monitoring-derived EWAC than the generic model approach. Implication for the use of a geo-referenced modeling approach in the risk assessment scheme is discussed as a generic-spatial approach, which can be used to provide more accurate exposure estimation with distribution information, using generally available data sources for a wide range of chemicals.

System boundary selection in life-cycle inventories using hybrid approaches.

Life-cycle assessment (LCA) is a method for evaluating the environmental impacts of products holistically, including direct and supply chain impacts. The current LCA methodologies and the standards by the International Organization for Standardization (ISO) impose practical difficulties for drawing system boundaries; decisions on inclusion or exclusion of processes in an analysis (the cutoff criteria) are typically not made on a scientific basis. In particular, the requirement of deciding which processes could be excluded from the inventory can be rather difficult to meet because many excluded processes have often never been assessed by the practitioner, and therefore, their negligibility cannot be guaranteed. LCA studies utilizing economic input-output analysis have shown that, in practice, excluded processes can contribute as much to the product system under study as included processes; thus, the subjective determination of the system boundary may lead to invalid results. System boundaries in LCA are discussed herein with particular attention to outlining hybrid approaches as methods for resolving the boundary selection problem in LCA. An input-output model can be used to describe at least a part of a product system, and an ISO-compatible system boundary selection procedure can be designed by applying hybrid input-output-assisted approaches. There are several hybrid input-output analysis-based LCA methods that can be implemented in practice for broadening system boundary and also for ISO compliance.