共查询到20条相似文献,搜索用时 15 毫秒
1.
Purpose
Plevin et al. (2014) reviewed relevant life cycle assessment (LCA) studies for biofuels and argued that the use of attributional LCA (ALCA) for estimating the benefits of biofuel policy is misleading. While we agree with the authors on many points, we found that some of the arguments by the authors were not presented fairly and that a number of specific points warrant additional comment. The main objective of this commentary is to examine the authors’ comparative statements between consequential LCA (CLCA) and ALCA.Methods
We examined the notion that the LCA world is divided into CLCA and ALCA. In addition, we evaluated the authors’ notion of “wrong” models.Results
We found that the authors were comparing an idealized, hypothetical CLCA with average (or less than average), real-life ALCAs. Therefore, we found that the comparison alone cannot serve as the basis for endorsing real-life CLCAs for biofuel policy. We also showed that there are many LCA studies that do not belong to either of the two approaches distinguished by the authors. Furthermore, we found that the authors’ notion of “wrong” models misses the essence of modeling and reveals the authors’ unwarranted confidence in certain modeling approaches.Conclusions
Dividing the LCA world into CLCAs and ALCAs overlooks the studies in between and hampers a constructive dialog about the creative use of modeling frameworks. Unreasonable confidence in certain modeling approaches based on their “conceptual” superiority does not help support “robust decision making” that should ultimately land itself on the ground. 相似文献2.
Lights and shadows in consequential LCA 总被引:1,自引:0,他引:1
Alessandra Zamagni Jeroen Guinée Reinout Heijungs Paolo Masoni Andrea Raggi 《The International Journal of Life Cycle Assessment》2012,17(7):904-918
Purpose
Consequential LCA (CLCA) is becoming widely used in the scientific community as a modelling technique which describes the consequences of a decision. However, despite the increasing number of case studies published, a proper systematization of the approach has not yet been achieved. This paper investigates the methodological implications of CLCA and the extent to which the applications are in line with the theoretical dictates. Moreover, the predictive and explorative nature of CLCA is discussed, highlighting the role of scenario modelling in further structuring the methodology.Methods
An extensive literature review was performed, involving around 60 articles published over a period of approximately 18?years, and addressing both methodological issues and applications. The information was elaborated according to two main aspects: what for (questions and modes of LCA) and what (methodological implications of CLCA), with focus on the nature of modelling and on the identification of the affected processes.Results and discussion
The analysis points out that since the modelling principles of attributional LCA (ALCA) and CLCA are the same, what distinguishes the two modes of LCA is the choice of the processes to be included in the system (i.e. in CLCA, those that are affected by the market dynamics). However, the identification of those processes is often done inconsistently, using different arguments, which leads to different results. We suggest the use of scenario modelling as a way to support CLCA in providing a scientifically sound basis to model specific product-related futures with respect to technology development, market shift, and other variables.Conclusions
The CLCA is a sophisticated modelling technique that provides a way to assess the environmental consequences of an action/decision by including market mechanisms into the analysis. There is still room for improvements of the method and for further research, especially in relation to the following aspects: clarifying when and which market information is important and necessary; understanding the role of scenario modelling within CLCA; and developing a procedure to support the framing of questions to better link questions to models. Moreover, we suggest that the logic of mechanisms could be the reading guide for overcoming the dispute between ALCA and CLCA. Going further, this logic could also be extended, considering CLCA as an approach??rather than as a modelling principle with defined rules??to deepen LCA, providing the conceptual basis for including more mechanisms than just the market ones. 相似文献3.
Caroline Gaudreault Réjean Samson Paul René Stuart 《The International Journal of Life Cycle Assessment》2010,15(2):198-211
Background, aim, and scope
North American pulp and paper mills are facing tremendous challenges, which may necessitate major mill modernizations. An example is process modification to reduce dependency on purchased power, which is an expensive resource. Such modifications may have environmental implications at the mills’ sites, on their product life cycle, and on other interconnected systems, and therefore, systematic tools such as life cycle assessment (LCA) need to be applied. Different LCA system boundary approaches can be used for such process design applications, and these approaches need to be compared to determine their respective benefits and limitations in this context. This study compares setting the system boundary according to a cradle-to-gate approach [attributional LCA (ALCA)] and a system expansion [consequential LCA (CLCA)] approach using a case study, which deals with implementing cogeneration and increased de-inked pulp production at an integrated newsprint mill. 相似文献4.
Background
Members of the calcium-activated chloride channel (CLCA) gene family have been suggested to possess a variety of functions including cell adhesion and tumor suppression. Expression of CLCA family members has mostly been analyzed in non-neural tissues. Here we describe the expression of mouse and human CLCA genes in the nervous system. 相似文献5.
John Harvey Alissa Kendall Nick Santero Thomas Van Dam In-Sung Lee Ting Wang 《The International Journal of Life Cycle Assessment》2011,16(9):944-946
Purpose
A workshop was convened on life cycle assessment (LCA) applied to pavement. The workshop’s primary goals were to establish common practices for conducting LCAs for pavements. In general, pavement LCA has been implemented without clear guidelines for modeling assumptions and reporting. This shortcoming has led to challenges in interpreting and comparing pavement LCA outcomes. 相似文献6.
Attributional and consequential LCA of milk production 总被引:1,自引:1,他引:0
Marlies A. Thomassen Randi Dalgaard Reinout Heijungs Imke de Boer 《The International Journal of Life Cycle Assessment》2008,13(4):339-349
Background, aim and scope Different ways of performing a life cycle assessment (LCA) are used to assess the environmental burden of milk production.
A strong connection exists between the choice between attributional LCA (ALCA) and consequential LCA (CLCA) and the choice
of how to handle co-products. Insight is needed in the effect of choice on results of environmental analyses of agricultural
products, such as milk. The main goal of this study was to demonstrate and compare ALCA and CLCA of an average conventional
milk production system in The Netherlands.
Materials and methods ALCA describes the pollution and resource flows within a chosen system attributed to the delivery of a specified amount of
the functional unit. CLCA estimates how pollution and resource flows within a system change in response to a change in output
of the functional unit. For an average Dutch conventional milk production system, an ALCA (mass and economic allocation) and
a CLCA (system expansion) were performed. Impact categories included in the analyses were: land use, energy use, climate change,
acidification and eutrophication. The comparison was based on four criteria: hotspot identification, comprehensibility, quality
and availability of data.
Results Total environmental burdens were lower when using CLCA compared with ALCA. Major hotspots for the different impact categories
when using CLCA and ALCA were similar, but other hotspots differed in contributions, order and type. As experienced by the
authors, ALCA and use of co-product allocation are difficult to comprehend for a consequential practitioner, while CLCA and
system expansion are difficult to comprehend for an attributional practitioner. Literature shows concentrates used within
ALCA will be more understandable for a feeding expert than the feed used within CLCA. Outcomes of CLCA are more sensitive
to uncertainties compared with ALCA, due to the inclusion of market prospects. The amount of data required within CLCA is
similar compared with ALCA.
Discussion The main cause of these differences between ALCA and CLCA is the fact that different systems are modelled. The goal of the
study or the research question to be answered defines the system under study. In general, the goal of CLCA is to assess environmental
consequences of a change in demand, whereas the goal of ALCA is to assess the environmental burden of a product, assuming
a status-quo situation. Nowadays, however, most LCA practitioners chose one methodology independent of their research question.
Conclusions This study showed it is possible to perform both ALCA (mass and economic allocation) and CLCA (system expansion) of milk.
Choices of methodology, however, resulted in differences in: total quantitative outcomes, hotspots, degree of understanding
and quality.
Recommendations and perspectives We recommend LCA practitioners to better distinguish between ALCA and CLCA in applied studies to reach a higher degree of
transparency. Furthermore, we recommend LCA practitioners of different research areas to perform similar case studies to address
differences between ALCA and CLCA of the specific products as the outcomes might differ from our study. 相似文献
7.
Coupling GIS and LCA for biodiversity assessments of land use 总被引:1,自引:0,他引:1
Roland Geyer David M. Stoms Jan P. Lindner Frank W. Davis Bastian Wittstock 《The International Journal of Life Cycle Assessment》2010,15(5):454-467
Purpose
Geospatial details about land use are necessary to assess its potential impacts on biodiversity. Geographic information systems (GIS) are adept at modeling land use in a spatially explicit manner, while life cycle assessment (LCA) does not conventionally utilize geospatial information. This study presents a proof-of-concept approach for coupling GIS and LCA for biodiversity assessments of land use and applies it to a case study of ethanol production from agricultural crops in California. 相似文献8.
Roland Geyer Jan P. Lindner David M. Stoms Frank W. Davis Bastian Wittstock 《The International Journal of Life Cycle Assessment》2010,15(7):692-703
Purpose
Geospatial details about land use are necessary to assess its potential impacts on biodiversity. Geographic information systems (GIS) are adept at modeling land use in a spatially explicit manner, while life cycle assessment (LCA) does not conventionally utilize geospatial information. This study presents a proof-of-concept approach for coupling GIS and LCA for biodiversity assessments of land use and applies it to a case study of ethanol production from agricultural crops in California. 相似文献9.
An M. De Schryver Mark J. Goedkoop Rob S. E. W. Leuven Mark A. J. Huijbregts 《The International Journal of Life Cycle Assessment》2010,15(7):682-691
Purpose
Uncertainties in land use damage modeling are recognized, but hardly quantified in life cycle assessment (LCA). The objective of this study is to analyze the influence of various key assumptions and uncertainties within the development of characterisation factors (CFs) for land use in LCA. We assessed the influence on land use CFs of (1) parameter uncertainty and (2) the choice for a constant or land use-specific species accumulation factor z and including or excluding regional effects. 相似文献10.
Comparative LCA of treatment options for US scrap tires: material recycling and tire-derived fuel combustion 总被引:1,自引:0,他引:1
Rebe Feraldi Sarah Cashman Melissa Huff Lars Raahauge 《The International Journal of Life Cycle Assessment》2013,18(3):613-625
Purpose
This life cycle assessment (LCA) study compares two prevalent end-of-life (EOL) treatment methods for scrap tires: material recycling and energy recovery. The primary intended use of the study results is to inform stakeholders of the relative environmental burdens and trade-offs associated with these two EOL vehicle tire treatment methods. The study supports prioritization of the waste treatment hierarchy for this material stream in the US.Methods
This LCA compares (1) material recycling through ambient-temperature mechanical processing and (2) energy recovery through co-incineration of both whole and preprocessed scrap tires at a cement kiln. The avoided burden recycling methodology reflects the substitution of virgin synthetic rubber used in asphalt modification with the ground tire rubber from material recycling and the substitution of conventional kiln fuels with the tire-derived fuel (TDF). Both attributional (ALCA) and consequential (CLCA) methodologies are used: the ALCA assesses the environmental profiles of the treatment methods and the CLCA examines the potential effects of shifting more scrap tires to material recycling. The attributional portion of the LCA study was conducted in accordance with ISO standards 14044 series.Results
The results in both methodological approaches indicate that the material recycling scenario provides greater impact reductions than the energy recovery scenario in terms of the examined environmental impact potentials: energy demand, iron ore consumption, global warming potential, acidification, eutrophication, smog formation, and respiratory effects. The additional impact reductions from material recycling are significant, and the establishment of new infrastructure required for a shift to material recycling incurs relatively insignificant burdens. Sensitivity analyses indicate that this conclusion does not change for (1) a range of TDF heating values, (2) a decrease in the mixed scrap tire rubber-to-steel composition ratio, (3) two alternative electricity grid fuel mixes with higher and lower carbon dioxide emission rankings than that of the baseline scenario, or (4) a comparison of material recycling to energy recovery when TDF is used in pulp and paper mills instead of cement kilns.Conclusions
These results provide a basis for more informed decision-making when prioritizing scrap tire waste treatment hierarchy. 相似文献11.
Xiaofen Li Wangxiong Hu Jiaojiao Zhou Yanqin Huang Jiaping Peng Ying Yuan Jiekai Yu Shu Zheng 《Cell communication and signaling : CCS》2017,15(1):38
Background
Chloride channel accessory 1 (CLCA1) belongs to the calcium-sensitive chloride conductance protein family, which is mainly expressed in the colon, small intestine and appendix. This study was conducted to investigate the functions and mechanisms of CLCA1 in colorectal cancer (CRC).Methods
The CLCA1 protein expression level in CRC patients was evaluated by enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC), and western blotting analysis. Using CRISPR/Cas9 technology, CLCA1-upregulated (CLCA1-ACT) and CLCA1-knockout cells (CLCA1-KO), as well as their respective negative controls (CLCA1-ACT-NC and CLCA1-KO-NC), were constructed from the SW620 cell line. Cell growth and metastatic ability were assessed both in vitro and in vivo. The association of CLCA1 with epithelial-mesenchymal transition (EMT) and other signaling pathways was determined by western blotting assays.Results
The expression level of CLCA1 in CRC tissues was significantly decreased compared with that in adjacent normal tissue (P< 0.05). Meanwhile, the serum concentration of CLCA1 in CRC patients was also significantly lower when compared with that of healthy controls (1.48?±?1.06 ng/mL vs 1.06?±?0.73 ng/mL, P?=?0.0018). In addition, CLCA1 serum concentration and mRNA expression level in CRC tissues were inversely correlated with CRC metastasis and tumor stage. Upregulated CLCA1 suppressed CRC growth and metastasis in vitro and in vivo, whereas inhibition of CLCA1 led to the opposite results. Increased expression levels of CLCA1 could repress Wnt signaling and the EMT process in CRC cells.Conclusions
Our findings suggest that increased expression levels of CLCA1 can suppress CRC aggressiveness. CLCA1 functions as a tumor suppressor possibly via inhibition of the Wnt/beta-catenin signaling pathway and the EMT process.12.
Hans-Jörg Althaus Peter de Haan Roland W. Scholz 《The International Journal of Life Cycle Assessment》2009,14(7):676-686
Background, aim, and scope
An inclusion of traffic noise effects could change considerably the overall results of many life cycle assessment (LCA) studies. However, at present, noise effects are usually not considered in LCA studies, mainly because the existing methods for their inclusion do not fulfill the requirement profile. Two methods proposed so far seem suitable for inclusion in generic life cycle inventory (LCI) databases, and a third allows for inter-modal comparison. The aim of this investigation is an in-depth analysis of the existing methods and the proposition of a framework for modeling road transport noise emissions in LCI in accordance to the requirement profile postulated in part 1. 相似文献13.
Gurbakhash S. Bhander Thomas H. Christensen Michael Z. Hauschild 《The International Journal of Life Cycle Assessment》2010,15(4):403-416
Background, aim, and scope
The management of municipal solid waste and the associated environmental impacts are subject of growing attention in industrialized countries. European Union has recently strongly emphasized the role of LCA in its waste and resource strategies. The development of sustainable solid waste management systems applying a life cycle perspective requires readily understandable tools for modeling the life cycle impacts of waste management systems. The aim of the paper is to demonstrate the structure, functionalities, and LCA modeling capabilities of the PC-based life cycle-oriented waste management model EASEWASTE, developed at the Technical University of Denmark specifically to meet the needs of the waste system developer with the objective to evaluate the environmental performance of the various elements of existing or proposed solid waste management systems. 相似文献14.
Frank Werner Hans-Jörg Althaus Klaus Richter Roland W. Scholz 《The International Journal of Life Cycle Assessment》2007,12(3):160-172
Background
In product life cycle assessment (LCA), the attribution of environmental interventions to a product under study is an ambiguous task. This is due to a) the simplistic modeling characteristics in the life cycle inventory step (LCI) of LCA in view of the complexity of our techno-economic system, and b) to the nontangible theoretical nature of the product system as a representation of the processes ‘causally’ linked to a product. Ambiguous methodological decisions during the setup of an LCI include the modeling of end-of-life scenarios or the choice of an allocation factor for the allocation of joint co-production processes. An important criterion for methodological decisions — besides the conformity with the relevant series of standards ISO 14 040 — is if the improvement options, which can be deduced from the LCI, are perceived by the decision-maker as to redirect the material flows at stake into more sustainable paths. 相似文献15.
Background and Objective
Life cycle assessment (LCA) is a highly data intensive undertaking, where collecting the life cycle inventory (LCI) data is the most labour intensive part. The aim of this paper is to show a method for representing the LCI in a simplified manner which not only allows an estimative, quantitative LCA, but also the application of advanced analysis methods to LCA. 相似文献16.
Viêt Cao Manuele Margni Basil D. Favis Louise Deschênes 《The International Journal of Life Cycle Assessment》2017,22(8):1220-1231
Purpose
Land use life cycle impact assessment is calculated as a distance to target value—the target being a desirable situation defined as a reference situation in Milà i Canals et al.’s (Int J Life Cycle Assess 12(1):2–4, 2007) widely accepted framework. There are several reference situations. This work aims to demonstrate the effect of the choice of reference situation on land impact indicators.Methods
Various reference situations are reported from the perspective of the object of assessment in land in life cycle assessment (LCA) studies and the modeling choices used in life cycle land impact indicators. They are analyzed and classified according to additional LCA modeling requirements: the type of LCA approach (attributional or consequential), cultural perspectives (egalitarian, hierarchist or individualist), and temporal preference. Sets of characterization factors (CF) by impact pathway, land cover, and region are calculated for different reference situations. These sets of CFs by reference situation are all compared with a baseline set. A case study on different crop types is used to calculate impact scores from different sets of CFs and compare them.Results and discussion
Comparing the rankings of the CFs from two different sets present inversions from 5% to 35% worldwide. Impact scores of the case study present inversions of 10% worldwide. These inversions demonstrate that the choice of a reference situation may reverse the LCA conclusions for the land use impact category. Moreover, these reference situations must be consistent with the different modeling requirements of an LCA study (approach, cultural perspective, and time preference), as defined in the goal and scope.Conclusions
A decision tree is proposed to guide the selection of a consistent and suitable choice of reference situation when setting other LCA modeling requirements.17.
Sensitivity coefficients for matrix-based LCA 总被引:2,自引:0,他引:2
Reinout Heijungs 《The International Journal of Life Cycle Assessment》2010,15(5):511-520
Background, aim, and scope
Matrix-based life cycle assessment (LCA) is part of the standard ingredients of modern LCA tools. An important aspect of matrix-based LCA that is straightforward to carry out, but that requires a careful mathematical handling, is the inclusion of sensitivity coefficients based on differentiating the matrix-based formulas. 相似文献18.
Can B. Aktas Melissa M. Bilec 《The International Journal of Life Cycle Assessment》2012,17(3):337-349
Purpose
Many life cycle assessment (LCA) studies do not adequately address the actual lifetime of buildings and building products, but rather assume a typical value. The goal of this study was to determine the impact of lifetime on residential building LCA results. Including accurate lifetime data into LCA allows a better understanding of a product’s environmental impact that would ultimately enhance the accuracy of LCA results. 相似文献19.
Guillaume Busset Matthieu Sangely Mireille Montrejaud-Vignoles Laurent Thannberger Caroline Sablayrolles 《The International Journal of Life Cycle Assessment》2012,17(3):325-336
Purpose
A life-cycle assessment (LCA) was performed to evaluate the environmental impacts of the remediation of industrial soils contaminated by polychlorobiphenyl (PCB). Two new bioremediation treatment options were compared with the usual incineration process. In this attributional LCA, only secondary impacts were considered. The contaminated soil used for the experiments contained 200 mg of PCB per kilogram. 相似文献20.
Anders S. G. Andrae Otto Andersen 《The International Journal of Life Cycle Assessment》2010,15(8):827-836