Quantitative Evaluation of Data Quality in Regional Material Flow Analysis

A method for quantitative evaluation of data quality in regional material flow analysis (MFA) is presented. The principal idea is that data quality is a multidimensional problem that cannot be judged by individual characteristics such as the data source, given that data from official statistics may not be per se of good quality and expert estimations may not be per se of bad quality, respectively. It appears that MFA data are never totally accurate and may have certain defects that impair the quality of the data in more than one dimension. The concept of MFA information defects is introduced, and these information defects are mathematically formalized as functions of data characteristics. They are quantified on a scale from 0 (no information defect) to 1 (maximum information defect). The proposed method is illustrated in a case study on palladium flows in Austria. A quantitative evaluation of data quality provides opportunities for understanding and assessing MFA results, their a priori information basis, their reliability in decision making, and data uncertainties. It is a formal step toward better reproducibility and more transparency in MFA.     

A Novel Approach to Characterize Data Uncertainty in Material Flow Analysis and its Application to Plastics Flows in Austria

Material flow analysis (MFA) is widely used to investigate flows and stocks of resources or pollutants in a defined system. Data availability to quantify material flows on a national or global level is often limited owing to data scarcity or lacking data. MFA input data are therefore considered inherently uncertain. In this work, an approach to characterize the uncertainty of MFA input data is presented and applied to a case study on plastics flows in major Austrian consumption sectors in the year 2010. The developed approach consists of data quality assessment as a basis for estimating the uncertainty of input data. Four different implementations of the approach with respect to the translation of indicator scores to uncertainty ranges (linear‐ vs. exponential‐type functions) and underlying probability distributions (normal vs. log‐normal) are examined. The case study results indicate that the way of deriving uncertainty estimates for material flows has a stronger effect on the uncertainty ranges of the resulting plastics flows than the assumptions about the underlying probability distributions. Because these uncertainty estimates originate from data quality evaluation as well as uncertainty characterization, it is crucial to use a well‐defined approach, building on several steps to ensure the consistent translation of the data quality underlying material flow calculations into their associated uncertainties. Although subjectivity is inherent in uncertainty assessment in MFA, the proposed approach is consistent and provides a comprehensive documentation of the choices underlying the uncertainty analysis, which is essential to interpret the results and use MFA as a decision support tool.     

A Data Characterization Framework for Material Flow Analysis

The validity of material flow analyses (MFAs) depends on the available information base, that is, the quality and quantity of available data. MFA data are cross‐disciplinary, can have varying formats and qualities, and originate from heterogeneous sources, such as official statistics, scientific models, or expert estimations. Statistical methods for data evaluation are most often inadequate, because MFA data are typically isolated values rather than extensive data sets. In consideration of the properties of MFA data, a data characterization framework for MFA is presented. It consists of an MFA data terminology, a data characterization matrix, and a procedure for database analysis. The framework facilitates systematic data characterization by cell‐level tagging of data with data attributes. Data attributes represent data characteristics and metainformation regarding statistical properties, meaning, origination, and application of the data. The data characterization framework is illustrated in a case study of a national phosphorus budget. This work furthers understanding of the information basis of material flow systems, promotes the transparent documentation and precise communication of MFA input data, and can be the foundation for better data interpretation and comprehensive data quality evaluation.     

Information Content,Complexity, and Uncertainty in Material Flow Analysis

Material Flow Analysis (MFA) is a useful method for modeling, understanding, and optimizing sociometabolic systems. Among others, MFAs can be distinguished by two general system properties: First, they differ in their complexity, which depends on system structure and size. Second, they differ in their inherent uncertainty, which arises from limited data quality. In this article, uncertainty and complexity in MFA are approached from a systems perspective and expressed as formally linked phenomena. MFAs are, in a graph‐theoretical sense, understood as networks. The uncertainty and complexity of these networks are computed by use of information measures from the field of theoretical ecology. The size of a system is formalized as a function of its number of flows. It defines the potential information content of an MFA system and holds as a reference against which complexity and uncertainty are gauged. Integrating data quality measures, the uncertainty of an MFA before and after balancing is determined. The actual information content of an MFA is measured by relating its uncertainty to its potential information content. The complexity of a system is expressed based on the configuration of each individual flow in relation to its neighboring flows. The proposed metrics enable different material flow systems to be compared to one another and the role of individual flows within a system to be assessed. They provide information useful for the design of MFAs and for the communication of MFA results. For exemplification, the regional MFAs of aluminum and plastics in Austria are analyzed in this article.     

Global Life Cycle Paper Flows,Recycling Metrics,and Material Efficiency

Despite major improvements in recycling over the last decades, the pulp and paper sector is a significant contributor to global greenhouse gas emissions and other environmental pressures. Further reduction of virgin material requirements and environmental impacts requires a detailed understanding of the global material flows in paper production and consumption. This study constructs a Sankey diagram of global material flows in the paper life cycle, from primary inputs to end‐of‐life waste treatment, based on a review of publicly available data. It then analyzes potential improvements in material flows and discusses recycling and material efficiency metrics. The article argues that the use of the collection rate as a recycling metric does not directly stimulate avoidance of virgin inputs and associated impacts. An alternative metric compares paper for recycling (recovered paper) with total fibrous inputs and indicates that the current rate is at just over half of the technical potential. Material efficiency metrics are found to be more useful if they relate to the reuse potential of wastes. The material balance developed in this research provides a solid basis for further study of global sustainable production and consumption of paper. The conclusions on recycling and efficiency should be considered for improving environmental assessment and stimulating a shift toward resource efficiency and the circular economy.     

Methodology and Indicators of Economy‐wide Material Flow Accounting

This contribution presents the state of the art of economy‐wide material flow accounting. Starting from a brief recollection of the intellectual and policy history of this approach, we outline system definition, key methodological assumptions, and derived indicators. The next section makes an effort to establish data reliability and uncertainty for a number of existing multinational (European and global) material flow accounting (MFA) data compilations and discusses sources of inconsistencies and variations for some indicators and trends. The results show that the methodology has reached a certain maturity: Coefficients of variation between databases lie in the range of 10% to 20%, and correlations between databases across countries amount to an average R² of 0.95. After discussing some of the research frontiers for further methodological development, we conclude that the material flow accounting framework and the data generated have reached a maturity that warrants material flow indicators to complement traditional economic and demographic information in providing a sound basis for discussing national and international policies for sustainable resource use.     

Uncertainties of Domestic Road Freight Statistics: Insights for Regional Material Flow Studies

Freight statistics are at the core of many studies in the field of industrial ecology because they depict the physical interdependencies of territories and allow links to be made worldwide between production and consumption. Recent studies have focused increasingly on subnational scales, often relying on domestic freight data. In this perspective, this article analyses the uncertainties of the French domestic road freight survey, road being by far the most common mode of transport in the country. Based on a statistical analysis of the survey, we propose a model to estimate the uncertainty of any given domestic road transport flow. We also assess uncertainty reduction when averaging the flows over several years, and obtain for instance a 30% reduction for a three‐year average. We then study the impact of the uncertainties on regional material flow studies such as the economy‐wide material flow analysis of the Bourgogne region. Overall the case studies advocate for a systematic assessment of freight uncertainties, as neither the disaggregation level nor the quantities traded are good enough predictors. This justifies the need for an easy‐to‐implement estimation model. Finally, basic comparison with the German and Swedish surveys tends to indicate that the main conclusions presented in this article are likely to be valid in other European countries.     

A Comprehensive Material Flow Account for Lao PDR to Inform Environmental and Sustainability Policy

Modern environmental and sustainability policy that acknowledges the linkages between socioeconomic processes and environmental pressures and impacts, and designs policies to decouple economic activity from environmental pressures and impacts, requires a sophisticated and comprehensive knowledge base. The concept of industrial metabolism provides a sound conceptual base, and material flow accounting—including primary material inputs and outflows of waste and emissions—provides a well‐accepted operationalization. Studies presenting a comprehensive material flow account for a national economy are rare, especially for developing countries. Countries such as Lao People's Democratic Republic (Lao PDR or Laos) face dual objectives of improving the material standard of living of their people while managing natural resources sustainably and mitigating adverse environmental impacts from growing resource throughput. Our research fills a knowledge gap, presents a comprehensive account of material inputs and outflows of waste and emissions for the Lao PDR national economy, and applies the accounting approach for a low‐income economy in Asia. We present a material balance for the years 2000 and 2015. For this research, we used data from Lao PDR national statistics and the accounting guidelines of the European Statistical Office (Eurostat), which pioneered the use of material flow data as part of its official statistical reporting. We demonstrate the feasibility of the accounting approach and discuss the robustness of results using uncertainty analysis conducted with statistical approaches commonly used in the field of industrial ecology, including Gauss's law of error propagation and Monte Carlo simulation. We find that the fast‐changing scale and composition of Lao PDR material flows, waste, and emissions presents challenges to the existing policy capacity and will require investment into governance of changed patterns of material use, waste disposal, and emissions. We consider the data analysis sufficiently robust to inform such a change in policy direction.     

Applying Fuzzy and Probabilistic Uncertainty Concepts to the Material Flow Analysis of Palladium in Austria

Material flow analysis (MFA) is a widely applied tool to investigate resource and recycling systems of metals and minerals. Owing to data limitations and restricted system understanding, MFA results are inherently uncertain. To demonstrate the systematic implementation of uncertainty analysis in MFA, two mathematical concepts for the quantification of uncertainties were applied to Austrian palladium (Pd) resource flows and evaluated: (1) uncertainty ranges expressed by fuzzy sets and (2) uncertainty ranges defined by normal distributions given as mean values and standard deviations. Whereas normal distributions represent the traditional approach for quantifying uncertainties in MFA, fuzzy sets may offer additional benefits in relation to uncertainty quantification in cases of scarce information. With respect to the Pd case study, the fuzzy representation of uncertain quantities is more consistent with the actual data availability in cases of incomplete databases, and fuzzy sets serve to highlight the effect of uncertainty on resource efficiency indicators derived from the MFA results. For both approaches, data reconciliation procedures offer the potential to reduce uncertainty and evaluate the plausibility of the model results. With respect to Pd resource management, improved formal collection of end‐of‐life (EOL) consumer products is identified as a key factor in increasing the recycling efficiency. In particular, the partial export of EOL vehicles represents a substantial loss of Pd from the Austrian resource system, whereas approximately 70% of the Pd in the EOL consumer products is recovered in waste management. In conclusion, systematic uncertainty analysis is an integral part of MFA required to provide robust decision support in resource management.     

Unified Materials Information System (UMIS): An Integrated Material Stocks and Flows Data Structure

Modern society depends on the use of many diverse materials. Effectively managing these materials is becoming increasingly important and complex, from the analysis of supply chains, to quantifying their environmental impacts, to understanding future resource availability. Material stocks and flows data enable such analyses, but currently exist mainly as discrete packages, with highly varied type, scope, and structure. These factors constitute a powerful barrier to holistic integration and thus universal analysis of existing and yet to be published material stocks and flows data. We present the Unified Materials Information System (UMIS) to overcome this barrier by enabling material stocks and flows data to be comprehensively integrated across space, time, materials, and data type independent of their disaggregation, without loss of information, and avoiding double counting. UMIS can therefore be applied to structure diverse material stocks and flows data and their metadata across material systems analysis methods such as material flow analysis (MFA), input‐output analysis, and life cycle assessment. UMIS uniquely labels and visualizes processes and flows in UMIS diagrams; therefore, material stocks and flows data visualized in UMIS diagrams can be individually referenced in databases and computational models. Applications of UMIS to restructure existing material stocks and flows data represented by block flow diagrams, system dynamics diagrams, Sankey diagrams, matrices, and derived using the economy‐wide MFA classification system are presented to exemplify use. UMIS advances the capabilities with which complex quantitative material systems analysis, archiving, and computation of material stocks and flows data can be performed.     

Environmental Impact Assessment of Wood Use in Japan through 2050 Using Material Flow Analysis and Life Cycle Assessment

In this study, we used material flow analysis and life cycle assessment to quantify the environmental impacts and impact reductions related to wood consumption in Japan from 1970 to 2013. We then conducted future projections of the impacts and reductions until 2050 based on multiple future scenarios of domestic forestry, wood, and energy use. An impact assessment method involving characterization, damage assessment, and integration with a monetary unit was used, and the results were expressed in Japanese yen (JPY). We found that environmental impacts from paper consumption, such as climate change and urban air pollution, were significant and accounted for 56% to 83% of the total environmental impacts between 1970 and 2013. Therefore, reductions of greenhouse gas, nitrogen oxide, and sulfur oxide emissions from paper production would be an effective measure to reduce the overall environmental impacts. An increase in wood use for building construction, civil engineering, furniture materials, and energy production could lead to reductions of environmental impacts (via carbon storage, material substitution, and fuel substitution) amounting to 357 billion JPY in 2050, which is equivalent to 168% of the 2013 levels. Particularly, substitution of nonwooden materials, such as cement, concrete, and steel, with wood products in building construction could significantly contribute to impact reductions. Although an increase of wood consumption could reduce environmental impacts, such as climate change, resource consumption, and urban air pollution, increased wood consumption would also be associated with land‐use impacts. Therefore, minimizing land transformations from forest to barren land will be important.     

Material Flow Accounts and Driving Factors of Economic Growth in the Philippines

This study looks into material flow trends in the Philippines from 1985 to 2010 by utilizing the methodology of economy‐wide material flow analysis. Using domestic data sources, this study presents disaggregated annual material flow trends in terms of four major material categories, namely: biomass; fossil energy carriers; ores and industrial minerals; and construction minerals. The results describe in detail the growth of material flows in a high‐density country at the onset of its development and reveal the shift of material consumption from dominance of renewable materials in 1985 to nonrenewable materials in 2010. IPAT analysis shows that the increase in material consumption was driven by population growth from 1985 to 1998 and by growth in affluence from 1999 to 2010. However, high inequalities amidst the growing economy suggest that a small group of wealthy people have influenced the acceleration of material consumption in the Philippines. The results of this research are intended to provide a thorough analysis of the processes occurring in Philippine economic growth in order to assist in tackling implications for the important issue of sustainable resource management.     

A Comparison of Two Methods to Conduct Material Flow Analysis on Waste Tires in a Small Island Developing State

The disposal of scrap tires is one of the biggest solid waste issues facing some small island developing states (SIDS) in the Caribbean. Dominica is a small Caribbean island nation that seeks to maintain its well‐founded image as the “Nature Island of the Caribbean.” The economy has seen a steadily increasing import of both tires and cars, with no mechanism for exportation of spent tires. This study used data gathered from both government and international sources to estimate the quantity of tires currently on the island and projected each year up to 2020 to determine potential reuse options. We performed a material flow analysis (MFA) using tire import, vehicle registration records, and projected per capita income to determine the expected accumulation of waste tires. Vehicle registration is expected to rise with the island's wealth, which will affect the annual flow of tires. Two methods were used to predict vehicle growth over time. Our analysis showed an average waste tire output from the economy of 47,000 to 50,000 passenger tire equivalents (PTEs) per year, or approximately 470 to 500 short tons per year of mass. Such an output does not justify large expenditures of tire shredding and processing equipment, but whole tire applications may be feasible as potential disposition options. The methods can be easily replicated to give low‐range and high‐range estimates of waste tires disposed in the environment.     

Particle Flow Analysis

Several authors have highlighted the potential risks of nanoparticles (NPs). Still, little is known about the magnitude of emissions of NPs from society. Here, the method of explorative particle flow analysis (PFA), a modification of the more well‐known substance flow analysis (SFA), is suggested. In explorative PFA, particle number instead of mass is used as flow and stock metric and explorative scenarios are used to account for potential technology diffusion and, consequently, potentially higher emissions. The method has been applied in a case study of the use phase of titanium dioxide (TiO₂) NPs in paint, sunscreen and self‐cleaning cement. The results indicate that the current largest emissions of TiO₂ NPs originate from the use of sunscreen. One scenario implies that, in the future, the largest flows and stocks of TiO₂ NPs could be related to self‐cleaning cement. Gaps in current knowledge are identified and suggestions for future research are given.     

The Sankey Diagram in Energy and Material Flow Management

The Sankey diagram is an important aid in identifying inefficiencies and potential for savings when dealing with resources. It was developed over 100 years ago by the Irish engineer Riall Sankey to analyze the thermal efficiency of steam engines and has since been applied to depict the energy and material balances of complex systems. The Sankey diagram is the main tool for visualizing industrial metabolism and hence is widely used in industrial ecology. In the history of the early 20th century, it played a major role when raw materials were scarce and expensive and engineers were making great efforts to improve technical systems. Sankey diagrams can also be used to map value flows in systems at the operational level or along global value chains. The article charts the historical development of the diagrams. After the First World War the diagrams were used to produce thermal balances of production plants for glass and cement and to optimize the energy input. In the 1930s, steel and iron ore played a strategic role in Nazi Germany. Their efficient use was highlighted with Sankey diagrams. Since the 1990s, these diagrams have become common for displaying data in life cycle assessments (LCAs) of products. Sankey diagrams can also be used to map value flows in systems at the operational level or along global value added chains. This article, the first of a pair, charts the historical development. The companion article discusses the methodology and the implicit assumptions of such Sankey diagrams.     

The Sankey Diagram in Energy and Material Flow Management

The Sankey diagram is an important aid in pointing up inefficiencies and potential for savings in connection with resource use. This article, the second of a pair, examines the use of Sankey diagrams in operational material flow management. The previous article described the development of the diagram and its use in the past.
Simple Sankey diagrams follow the requirement of conservation of energy or mass and allow a physical view of production systems. Advanced diagrams integrate stocks of materials beside the flows or show the different (ecological) quality of the materials. For the purpose of management, however, a further step is necessary: to illustrate the economic value of the energy and material flows and to use information from cost accounting. The use of flow charts showing added value or the costs of energy and material flows is particularly important for production systems. This article describes examples of each of these uses as well as assumptions that must be taken into account for Sankey diagrams to be used as an effective aid for decision-making in business and public policy.     

Ship Breaking and the Steel Industry in Bangladesh: A Material Flow Perspective

Bangladesh has emerged as a leading ship breaking nation. We conducted a material flow analysis of steel in Bangladesh with an emphasis on the ship breaking industry (SBI). The total aggregate domestic steel consumption in fiscal year (FY) 2010 was 2,930,000 tonnes (t) in Bangladesh; SBI met approximately 51% of the demand for raw materials and 37% of the demand for finished steel products. Rolling industries output in FY2010 was 1,451,000 t; 23% of the input for this production was from ship breaking sources. Dismantled ships also generate high‐quality reusable steel scraps. SBI was found to be the sole source of scraps for small rerolling industries in Bangladesh, and their output in 2008 more than doubled as compared to 2005. Larger rolling industries fulfilled their input needs for steel scraps by using both SBI and imported materials. We found a sharp increase in input imports during the global ship breaking recession in 2003–2007 and when Bangladesh's SBI faced a temporary ban in 2010. Induction furnaces in Bangladesh in FY2010 produced a total of 787,000 t of billets; more than 40% was from ship‐sourced scraps. In 2008, the country's steel consumption was 3,220,000 t, that is, 22 kilograms per person, and the intensity of steel use was 40 grams per U.S. dollar, which was much higher than that of other developing countries with a similar per capita gross domestic product (GDP). The country exhibited a high level of steel consumption relative to its GDP, which is indicative of the contribution of SBI.     

Consumption‐based Material Flow Accounting

In 2007, imports accounted for approximately 34% of the material input (domestic extraction and imports) into the Austrian economy and almost 60% of the GDP stemmed from exports. Upstream material inputs into the production of traded goods, however, are not yet included in the standard framework of material flow accounting (MFA). We have reviewed different approaches accounting for these upstream material inputs, or raw material equivalents (RME), positioning them in a wider debate about consumption‐based perspectives in environmental accounting. For the period 1995–2007, we calculated annual RME of Austria's trade and consumption applying a hybrid approach. For exports and competitive imports, we used an environmentally extended input‐output model of the Austrian economy, based on annual supply and use tables and MFA data. For noncompetitive imports, coefficients for upstream material inputs were extracted from life cycle inventories. The RME of Austria's imports and exports were approximately three times larger than the trade flows themselves. In 2007, Austria's raw material consumption was 30 million tonnes or 15% higher than its domestic material consumption. We discuss the material composition of these flows and their temporal dynamics. Our results demonstrate the need for a consumption‐based perspective in MFA to provide robust indicators for dematerialization and resource efficiency analysis of open economies.     

Material Flow Indicators in the Czech Republic in Light of the Accession to the European Union

This article deals with the economy‐wide material flows in the Czech Republic in 1990–2006. It presents in brief the overall trends of the material flow indicators in 1990–2002. The major part of the article is focused on the years 2002–2006, which immediately preceded and followed the accession of the Czech Republic to the European Union in 2004. It is shown that this accession had quite a significant impact on the volume and character of the material flows of the Czech Republic. The accession was beneficial from an economic point of view, as it allowed for an increased supply of materials needed for economic growth. Furthermore, it was accompanied by an improvement in the efficiency of material transformation into economic output. From an environmental and broader sustainability point of view, however, this accession brought about some controversial outcomes. There was a significant increase in the net export of environmental pressure, on one hand, and an increase in net additions to the physical stock of the economy, on the other. Although the former is controversial from the viewpoint of equity in sharing area and resources, the latter places an additional burden on future generations because all physical stocks will turn into waste and emissions at some point, when their life span expires.     

A Material Flow Accounting Case Study of the Lisbon Metropolitan Area using the Urban Metabolism Analyst Model

This article describes a new methodological framework to account for urban material flows and stocks, using material flow accounting (MFA) as the underlying method. The proposed model, urban metabolism analyst (UMAn), bridges seven major gaps in previous urban metabolism studies: lack of a unified methodology; lack of material flows data at the urban level; limited categorizations of material types; limited results about material flows as they are related to economic activities; limited understanding of the origin and destination of flows; lack of understanding about the dynamics of added stock; and lack of knowledge about the magnitude of the flow of materials that are imported and then, to a great extent, exported. To explore and validate the UMAn model, a case study of the Lisbon Metropolitan Area was used. An annual time series of material flows from 2003 to 2009 is disaggregated by the model into 28 material types, 55 economic activity categories, and 18 municipalities. Additionally, an annual projection of the obsolescence of materials for 2010–2050 was performed. The results of the case study validate the proposed methodology, which broadens the contribution of existing urban MFA studies and presents pioneering information in the field of urban metabolism. In particular, the model associates material flows with economic activities and their spatial location within the urban area.