Choice of system boundaries in life cycle assessment

Tillman, Anne‐Marie; Ekvall, Tomas; Baumann, Henrikke; Rydberg, Tomas

doi:10.1016/0959-6526(94)90021-3

Cited by 195 publications

(105 citation statements)

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“…Similarly, the impacts from use of lubricating oil (losses during driving) are excluded as these will also be equivalent for each case. Removal of these life-cycle phases from consideration is consistent with the principle of excluding identical activities for comparative assessments (12,14).…”

Section: Methodsmentioning

confidence: 92%

Environmental Assessment of Used Oil Management Methods

Boughton

Horvath

2003

Environ. Sci. Technol.

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The 1 billion gal of used oil generated in the U.S. each year are managed in three primary ways: rerefined into base oil for reuse, distilled into marine diesel oil fuel, and marketed as untreated fuel oil. Management of used oil has local, regional and global impacts. Because of the globally distributed nature of fuel markets, used oil as fuel has localized and regional impacts in many areas. In this paper, the human health and environmental tradeoffs of the management options are quantified and characterized. The goal of this study was to assess and compare the environmental impacts and benefits of each management method in a product end-of-life scenario using a life-cycle assessment (LCA) approach. A life-cycle inventory showed that 800 mg of zinc and 30 mg of lead air emissions may result from the combustion of 1 L of used oil as fuel (50−100 times that of crude-derived fuel oils). As an example, up to 136 Mg of zinc and 5 Mg of lead air emissions may be generated from combustion of over 50 M gal of California-generated used oil each year. While occurring elsewhere, these levels are significant (of the same magnitude as reported total stationary source emissions in California). An impact assessment showed that heavy metals-related toxicity dominates the comparison of management methods. Zinc and lead emissions were the primary contributors to the terrestrial and human toxicity impact potentials that were calculated to be 150 and 5 times higher, respectively, for used oil combusted as fuel than for rerefining or distillation. Low profits and weak markets increasingly drive the used oil management method selection toward the untreated fuel oil market. Instead, both the rerefining and distillation methods and associated product markets should be strongly supported because they are environmentally preferable to the combustion of unprocessed used oil as fuel.

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Section: Methodsmentioning

confidence: 92%

Environmental Assessment of Used Oil Management Methods

Boughton

Horvath

2003

Environ. Sci. Technol.

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“…This procedure reflects as closely as possible the consequences of a specific change in demand for a co-product (Weidema and Norris 2002). Guinée et al (2002) added to this definition, based on Tillman et al (1994), not to add functions but to subtract them from those alternatives providing additional functions, the so-called substitution or avoided-burden method. When system expansion is performed, the environmental load of the avoided burden in most studies is subtracted.…”

Section: System Expansionmentioning

confidence: 99%

Attributional and consequential LCA of milk production

Thomassen

Dalgaard

Heijungs

et al. 2008

Int J Life Cycle Assess

287

159

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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. Int J Life Cycle Assess (2008) 13:339-349 DOI 10.1007 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 L...

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“…Algumas alternativas têm sido construídas como as ACVs parciais feitas do "berço à fábrica" ou então da "fábrica ao túmulo" (SHEN; PATEL, 2008). Assim, a definição das fronteiras das avaliações de ciclo de vida devem incluir as atividades relevantes para a proposta do estudo (TILLMAN et al, 1994 Logo, observa-se a relação existente entre aspectos e impactos ambientais de operações e produtos, não sendo possível desvincular a análise ambiental do produto da análise ambiental de seu processo de produção. Torna-se importante o levantamento dos aspectos e impactos ambientais ligados ao processo produtivo das embalagens, a fim de verificar a influência destas sobre o meio ambiente e visando possíveis alternativas que minimizem os impactos gerados.…”

Section: Questões Ambientais Do Segmento De Perfumariaunclassified

Identificação de aspectos ambientais relacionados à produção de embalagens de perfumaria: contribuição para projetos sustentáveis

2012

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The need for controlling atmospheric emissions and solid waste and effluent generation in industrial processes has stimulated many industries to adopt several different methods and tools for the development of sustainable products. Packaging can also be considered a product since it has its own life cycle, and its impactsResumo: A necessidade de controle das emissões atmosféricas e da geração de resíduos sólidos e efluentes nos processos produtivos faz com que muitas empresas, atualmente, adotem diversas ferramentas e metodologias para o desenvolvimento de produtos sustentáveis. As embalagens também são consideradas produtos, pois têm um ciclo de vida próprio e seus impactos estão ligados à extração de matéria-prima, fabricação, transporte e destinação pós-consumo, em que se tornam um importante componente do lixo urbano. No segmento de Higiene Pessoal, Perfumaria e Cosméticos, o crescimento do mercado e do consumo de produtos tem acarretado impactos ambientais oriundos da produção das embalagens utilizadas para acondicionamento dos produtos. O processo produtivo destas embalagens gera resíduos sólidos, efluentes líquidos, emissões atmosféricas, ruídos e vibrações. O presente trabalho identificou e organizou os principais aspectos e impactos ambientais relacionados ao processo produtivo de embalagens do segmento de perfumaria, envolvendo a seleção e transformação de materiais e processos, servindo como um instrumento de subsídio na proposição de melhorias em projetos e processos mais sustentáveis. O método de pesquisa consistiu em coleta bibliográfica e documental acerca do tema e compilação de dados estatísticos. Para a abordagem da cadeia produtiva das embalagens realizaram-se observações diretas nas instalações produtivas das indústrias de fabricação e decoração de embalagens do segmento de perfumaria. A pesquisadora realizou tanto entrevistas abertas e não estruturadas (por conversação) como aplicação de questionários via formato eletrônico com técnicos responsáveis pelas atividades produtivas, observando critérios técnicos e ambientais sugeridos por autores do âmbito ambiental organizacional, legislação ambiental e normatizações da ABNT ISO 14001:2004. (ASSOCIAÇÃO..., 2004. A análise estrutural das embalagens permitiu a identificação de seus componentes, materiais e processos de fabricação. Os fluxogramas de processo e o método de listagem permitiram a identificação dos aspectos e seu relacionamento com as etapas do processo produtivo no qual são gerados. Concluiu-se, a partir dos resultados, que todos os processos de fabricação analisados apresentaram aspectos ambientais relacionados com o consumo de recursos naturais, geração de efluentes, emissões atmosféricas e geração de resíduos com efeitos em nível local, regional e global.Palavras-chave: Desenvolvimento sustentável. Embalagens. Perfumaria. Avaliação de ciclo de vida. Aspectos ambientais.Identificação de aspectos ambientais relacionados à produção de embalagens de perfumaria -contribuição para projetos sustentáveis

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Choice of system boundaries in life cycle assessment

Cited by 195 publications

References 0 publications

Environmental Assessment of Used Oil Management Methods

Environmental Assessment of Used Oil Management Methods

Attributional and consequential LCA of milk production

Identificação de aspectos ambientais relacionados à produção de embalagens de perfumaria: contribuição para projetos sustentáveis

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