In recent years, the building sector has highlighted the importance of operational energy and efficient resource management in order to reduce the environmental impacts of buildings. However, differences in building-specific properties (building location, size, construction material, etc.) pose a major challenge in development of generic policy on buildings. The aim of this study was to investigate the relationship between energy and resource management policies, and building-specific characteristics on environmental impacts of refurbished office buildings in New Zealand.
MethodsLife Cycle Assessment (LCA) was performed for 17 office buildings operating under seven representative climatic conditions found in New Zealand. Each building was assessed under four policy scenarios: (i) business-as-usual, (ii) use of on-site photovoltaic (PV) panels, (iii) electricity supply from a renewable energy grid, and (iv) best practice construction activities adopted at site. The influence of 15 building-specific characteristics in combination with each scenario was evaluated. The study adopted regression analysis, more specifically Kruskal-Wallis and General Additive Modeling (GAM), to support interpretation of the LCA results.
Results and discussionAll the chosen policies can significantly contribute to climate change mitigation as compared to business-as-usual. However, the Kruskal-Wallis results highlight policies on increasing renewable energy sources supplying national grid electricity can substantially reduce the impacts across most environmental impact categories. Better construction practices should be prioritized over PV installation as use of on-site PV significantly increases the environmental impacts related to use of resources. The GAM results show on-site PV could be installed in low-rise buildings in regions with long sunshine hours. The results also show the strong influence of façade elements and technical equipment in determining the environmental performance of small and large buildings, respectively. In large multi-storied buildings, efficient HVAC and smaller window area are beneficial features, while in small buildings the choice of façade materials with low embodied impacts should be prioritized.
ConclusionsIn general, the study highlighted the importance of policies on increasing renewable energy supply from national grid electricity to substantially reduce most of the impacts related to buildings. In addition, the study also highlighted the importance of better construction practices and building-specific characteristics to reduce the impacts related to resource use. These findings can support policy makers to prioritize strategies to improve the environmental performance of existing buildings in New Zealand and in regions with similar building construction and climate.
相似文献Trade is increasingly considered a significant contributor to environmental impacts. The assessment of the impacts of trade is usually performed via environmentally extended input–output analysis (EEIOA). However, process-based life cycle assessment (LCA) applied to traded goods allows increasing the granularity of the analysis and may be essential to unveil specific impacts due to traded products.
MethodsThis study assesses the environmental impacts of the European trade, considering two modelling approaches: respectively EEIOA, using EXIOBASE 3 as supporting database, and process-based LCA. The interpretation of the results is pivotal to improve the robustness of the assessment and the identification of hotspots. The hotspot identification focuses on temporal trends and on the contribution of products and substances to the overall impacts. The inventories of elementary flows associated with EU trade, for the period 2000–2010, have been characterized considering 14 impact categories according to the Environmental Footprint (EF2017) Life Cycle Impact Assessment method.
Results and discussionThe two modelling approaches converge in highlighting that in the period 2000–2010: (i) EU was a net importer of environmental impacts; (ii) impacts of EU trade and EU trade balance (impacts of imports minus impacts of exports) were increasing over time, regarding most impact categories under study; and (iii) similar manufactured products were the main contributors to the impacts of exports from EU, regarding most impact categories. However, some results are discrepant: (i) larger impacts are obtained from IO analysis than from process-based LCA, regarding most impact categories, (ii) a different set of most contributing products is identified by the two approaches in the case of imports, and (iii) large differences in the contributions of substances are observed regarding resource use, toxicity, and ecotoxicity indicators.
ConclusionsThe interpretation step is crucial to unveil the main hotspots, encompassing a comparison of the differences between the two methodologies, the assumptions, the data coverage and sources, the completeness of inventory as basis for impact assessment. The main driver for the observed divergences is identified to be the differences in the impact intensities of goods, both induced by inherent properties of the IO and life cycle inventory databases and by some of this study’s modelling choices. The combination of IO analysis and process-based LCA in a hybrid framework, as performed in other studies but generally not at the macro-scale of the full trade of a country or region, appears a potential important perspective to refine such an assessment in the future.
相似文献An estimation of the environmental impact of buildings by means of a life cycle assessment (LCA) raises uncertainty related to the parameters that are subject to major changes over longer time spans. The main aim of the present study is to evaluate the influence of modifications in the electricity mix and the production efficiency in the chosen reference year on the embodied impacts (i.e., greenhouse gas (GHG) emissions) of building materials and components and the possible impact of this on future refurbishment measures.
MethodsA new LCA methodological approach was developed and implemented that can have a significant impact on the way in which existing buildings are assessed at the end of their service lives. The electricity mixes of different reference years were collected and assessed, and the main datasets and sub-datasets were modified according to the predefined substitution criteria. The influence of the electricity-mix modification and production efficiency were illustrated on a selected existing reference building, built in 1970. The relative contribution of the electricity mix to the embodied impact of the production phase was calculated for four different electricity mixes, with this comprising the electricity mix from 1970, the current electricity mix and two possible future electricity-mix scenarios for 2050. The residual value of the building was also estimated.
Results and discussionIn the case presented, the relative share of the electricity mix GHG emission towards the total value was as high as 20% for separate building components. If this electricity mix is replaced with an electricity mix having greater environmental emissions, the relative contribution of the electricity mix to the total emissions can be even higher. When, by contrast, the modified electricity mix is almost decarbonized, the relative contribution to the total emissions may well be reduced to a point where it becomes negligible. The modification of the electricity mix can also influence the residual value of a building. In the observed case, the differences due to different electricity mixes were in the range of 10%.
ConclusionsIt was found that those parameters that are subject to a major change during the reference service period of the building should be treated dynamically in order to obtain reliable results. Future research is foreseen to provide additional knowledge concerning the influence of dynamic parameters on both the use phase and the end-of-life phase of buildings, and these findings will also be important when planning future refurbishment measures.
相似文献The building sector is one of the most relevant sectors in terms of environmental impact. Different functional units (FUs) can be used in life cycle assessment (LCA) studies for a variety of purposes. This paper aimed to present different FUs used in the LCA of buildings and evaluate the influence of FU choice and setting in comparative studies.
MethodsAs an example, we compared the “cradle to grave” environmental performance of four typical Brazilian residential buildings with different construction typologies, i.e., multi-dwelling and single dwelling, each with high and basic standards. We chose three types of FU for comparison: a dwelling with defined lifetime and occupancy parameters, an area of 1 m2 of dwelling over a year period, and the accommodation of an occupant person of the dwelling over a day.
Results and discussionThe FU choice was found to bias the results considerably. As expected, the largest global warming indicator (GWi) values per dwelling unit and occupant were identified for the high standard dwellings. However, when measured per square meter, lower standard dwellings presented the largest GWi values. This was caused by the greater concentration of people per square meter in smaller area dwellings, resulting in larger water and energy consumption per square meter. The sensitivity analysis of FU variables such as lifetime and occupancy showed the GWi contribution of the infrastructure more relevant compared with the operation in high and basic standard dwellings. The definition of lifetime and occupancy parameters is key to avoid bias and to reduce uncertainty of the results when performing a comparison of dwelling environmental performances.
ConclusionsThis paper highlights the need for adequate choice and setting of FU to support intended decision-making in LCA studies of the building sector. The use of at least two FUs presented a broader picture of building performance, helping to guide effective environmental optimization efforts from different approaches and levels of analysis. Information regarding space, time, and service dimensions should be either included in the FU setting or provided in the building LCA study to allow adjustment of the results for subsequent comparison.
相似文献To reduce the environmental impact of the building sector, environmental targets considering the full life cycle of buildings can be supportive. In recent years, various benchmarks based on Life Cycle Assessment (LCA) have been developed as part of regulations, labelling systems, sustainability rating tools and research studies. The objective of this paper is to critically analyse 23 existing benchmarking systems focusing on the benchmark methodology but also on the benchmark applications and communication.
MethodsThe critical literature review consists of two parts. In a first part, the choices related to the assessment method, functional equivalent, definition of benchmark values, benchmark scope, benchmark applications and benchmark communication are compared. In the second part, benchmark values are compiled from literature and statistically analysed.
Results and discussionThe comparative analysis allows to identify the main approaches and methods used in benchmarking systems. For each evaluation aspect, the strengths and weaknesses of the various approaches are highlighted. The statistical analysis provides insight in the spread of benchmark values. Important variations are found between the literature sources which can be explained by differences in benchmark approach, scope, system boundaries and applications.
ConclusionsBased on the comparative analysis, recommendations are formulated for the development of LCA benchmarks for the building sector. The results of the statistical analysis furthermore provide reference values which can be used for the validation of future benchmarks. For global warming, the statistical values for the full life cycle impacts (i.e. embodied and operational impacts) range from about 15 up to 35 kg CO2 eq/m2.a.
相似文献Changes in the production of Australian cotton lint are expected to have a direct environmental impact, as well as indirect impacts related to co-product substitution and induced changes in crop production. The environmental consequences of a 50% expansion or contraction in production were compared to Australian cotton production’s current environmental footprint. Both were then assessed to investigate whether current impacts are suitable for predicting the environmental impact of a change in demand for cotton lint.
MethodsA consequential life cycle assessment (LCA) model of Australian cotton lint production (cradle-to-gin gate) was developed using plausible scenarios regarding domestic regions and technologies affected by changes in supply, with both expansion (additional cotton) and contraction (less cotton) being modelled. Modelling accounted for direct impacts from cotton production and indirect impacts associated with changes to cotton production, including co-product substitution and changes to related crops at regional and global scales. Impact categories assessed included climate change, fossil energy demand, freshwater consumption, water stress, marine and freshwater eutrophication, land occupation and land-use change.
Results and discussionFor both the expansion and contraction scenarios, the changes to climate change impacts (including iLUC) and water impacts were less than would be assumed from current production as determined using attributional LCA. However, the opposite was true for all other impact categories, indicating trade-offs across the impact categories. Climate change impacts under both scenarios were relatively minor because these were largely offset by iLUC. Similarly, under the contraction scenario, water impacts were dominated by indirect impacts associated with regional crops. A sensitivity analysis showed that the results were sufficiently robust to indicate the quantum of changes that could be expected.
ConclusionsA complex array of changes in technologies, production regions and related crops were required to model the environmental impacts of a gross change in cotton production. Australian cotton lint production provides an example of legislation constraining the direct water impacts of production, leading to a contrast between impacts estimated by attributional and consequential LCA. This model demonstrated that indirect products and processes are important contributors to the environmental impacts of Australian cotton lint.
相似文献The purpose of this article is to find a suitable life cycle assessment (LCA) method to quantify the most important environmental burdens caused by construction processes of torrent control structures. To find these environmental burdens, 17 construction projects of the “Austrian Service for Torrent and Avalanche Control” (WLV) were analyzed using the “cradle to gate with options” LCA methodology (CEN, 2013).
MethodsThis article explains an LCA methodology for the product stage and the construction process of torrent control structures following existing standards. The iterative approach of LCA methodology (ISO, 2006a) was used to record all important processes of the system and to supplement missing information. The LCA methodology has been developed from existing standards of the construction and product sector. Since the production of some construction materials takes place locally, the generic data, for Austria, was adapted. Wood inherent biogenic carbon and primary energy, used as raw material, are treated as materials inherent properties (CEN, 2014). The contribution of the various processes was reproduced by hotspot.
Results and discussionHotspots of the different stages are related to the construction materials used. The emissions and primary energy inputs in the product stage are clearly dominated by concrete and steel. If these two materials are used sparingly, the focus is on machine application and transportation. Depending on the selected scenarios, the smallest share of emissions, in relation to the total result of product and construction stage emitted by transport, is 3% and the maximum share is 69%. The greatest environmental impacts in the construction stage are caused by excavation work and transportation on-site. With an average of 4% in the construction stage, the transport of workers to the construction site cannot be neglected as is done in the building sector.
ConclusionsThe conclusion of this study is that existing LCA models can be adapted to protective structures. In contrast to conventional buildings, the construction process and transportation are much more important and cannot be neglected. Shifting the hotspots to these processes requires specific calculation rules for that particular field. There is still a need for research to find a suitable functional unit and to develop a methodology for the use and end of life stage of these structures.
相似文献Purpose
Since the construction sector is a considerable energy consumer and greenhouse gas (GHG) producer, the EU rules strive to build nearly zero-energy buildings, by reducing the operative energy and yearning for on-site energy production. This article underlines the necessity to go beyond the energy evaluations and move towards the environmental assessment in a life cycle perspective, by comparing the impacts due to building materials and energy production devices.Methods
We compared the operational energy impacts and those of technologies and materials carrying out a life cycle assessment (LCA; ISO 14040, ISO 14044, EN 15643–2, EN 15978) on a nearly zero-energy building (ZEB), a residential complex with 61 apartments in four buildings, situated near Milan (Italy). We consider all life cycle phases, including production, transport, building site activities, use and maintenance; the materials inventory was filled out collecting data from invoices paid, building site reports, construction drawings and product data sheets. To make the assessment results comparable, we set a functional unit of 1 m2 of net floor area in 1 year (1 m2y), upon a lifespan of 100 years. The environmental data were acquired from Ecoinvent 2.2.Results and discussion
The results highlight the important role of the pre-use and maintenance phases in building life so that in a nearly ZEB, the environmental impacts linked to the use are no longer the major proportion: the pre-use phase accounts for 56 %, while the operative energy is only 31 % of the total. For this reason, if the environmental assessment of the case study was shrunk to the operational consumption, only one third of the impacts would be considered. The consumption of non-renewable resources after 100 years are 193,950 GJ (133.5 kWh/m2y); the GHG emissions are 15,300 t (37.8 kg of CO2?eq/m2y). In the pre-use phase, structures have the major impacts (50 %) and the load of system components is unexpectedly high (12 %) due to the ambition of on-site energy production.Conclusions
Paying attention to the operative energy consumption seems to address to only one third of the environmental impacts of buildings: the adoption of LCA as a tool to guide the design choices could help to identify the solution which ensures the lowest overall impact on the whole life, balancing the options of reducing the energy requirements, the on-site production from renewable sources and the limitation of the impacts due to building components (simpler and more durable).Purpose
With the increasing concerns related to integration of social and economic dimensions of the sustainability into life cycle assessment (LCA), traditional LCA approach has been transformed into a new concept, which is called as life cycle sustainability assessment (LCSA). This study aims to contribute the existing LCSA framework by integrating several social and economic indicators to demonstrate the usefulness of input–output modeling on quantifying sustainability impacts. Additionally, inclusion of all indirect supply chain-related impacts provides an economy-wide analysis and a macro-level LCSA. Current research also aims to identify and outline economic, social, and environmental impacts, termed as triple bottom line (TBL), of the US residential and commercial buildings encompassing building construction, operation, and disposal phases.Methods
To achieve this goal, TBL economic input–output based hybrid LCA model is utilized for assessing building sustainability of the US residential and commercial buildings. Residential buildings include single and multi-family structures, while medical buildings, hospitals, special care buildings, office buildings, including financial buildings, multi-merchandise shopping, beverage and food establishments, warehouses, and other commercial structures are classified as commercial buildings according to the US Department of Commerce. In this analysis, 16 macro-level sustainability assessment indicators were chosen and divided into three main categories, namely environmental, social, and economic indicators.Results and discussion
Analysis results revealed that construction phase, electricity use, and commuting played a crucial role in much of the sustainability impact categories. The electricity use was the most dominant component of the environmental impacts with more than 50 % of greenhouse gas emissions and energy consumption through all life cycle stages of the US buildings. In addition, construction phase has the largest share in income category with 60 % of the total income generated through residential building’s life cycle. Residential buildings have higher shares in all of the sustainability impact categories due to their relatively higher economic activity and different supply chain characteristics.Conclusions
This paper is an important attempt toward integrating the TBL perspective into LCSA framework. Policymakers can benefit from such approach and quantify macro-level environmental, economic, and social impacts of their policy implications simultaneously. Another important outcome of this study is that focusing only environmental impacts may misguide decision-makers and compromise social and economic benefits while trying to reduce environmental impacts. Hence, instead of focusing on environmental impacts only, this study filled the gap about analyzing sustainability impacts of buildings from a holistic perspective. 相似文献Digital fabrication is revolutionizing architecture, enabling the construction of complex and multi-functional building elements. Multi-functionality is often achieved through material reduction strategies such as functional or material hybridization. However, these design strategies may increase environmental impacts over the life cycle. The integration of functions may hinder the maintenance and shorten the service life. Moreover, once a building element has reached the end of life, hybrid materials may influence negatively its recycling capacity. Consequently, the aim of this paper is to analyze the influence of multi-functionality in the environmental performance of two digitally fabricated architectural elements: The Sequential Roof and Concrete-Sandstone Composite Slab and to compare them with existing standard elements.
MethodsA method based on the life-cycle assessment (LCA) framework is applied for the evaluation of the environmental implications of multi-functionality in digital fabrication. The evaluation consists of the comparison of embodied impacts between a multi-functional building element constructed with digital fabrication techniques and a conventional one, both with the same building functions. Specifically, the method considers the lifetime uncertainty caused by multi-functionality by considering two alternative service life scenarios during the evaluation of the digitally fabricated building element. The study is extended with a sensitivity analysis to evaluate the additional environmental implications during end-of-life processing derived from the use of hybrid materials to achieve multi-functionality in architecture.
Results and discussionThe evaluation of two case studies of digitally fabricated architecture indicates that their environmental impacts are very sensitive to the duration of their service life. Considering production and life span phases, multi-functional building elements should have a minimum service life of 30 years to bring environmental benefits over conventional construction. Furthermore, the case study of Concrete-Sandstone Composite Slab shows that using hybrid materials to achieve multi-functionality carries important environmental consequences at the end of life, such as the emission of air pollutants during recycling.
ConclusionsThe results from the case studies allow the identification of key environmental criteria to consider during the design of digitally fabricated building elements. Multi-functionality provides material efficiency during production, but design adaptability must be a priority to avoid a decrease in their environmental performance. Moreover, the high environmental impacts caused by end-of-life processing should be compensated during design.
相似文献Despite the wide use of LCA for environmental profiling, the approach for determining the system boundary within LCA models continues to be subjective and lacking in mathematical rigor. As a result, life cycle models are often developed in an ad hoc manner, and are difficult to compare. Significant environmental impacts may be inadvertently left out. Overcoming this shortcoming can help elicit greater confidence in life cycle models and their use for decision making.
MethodsThis paper describes a framework for hybrid life cycle model generation by selecting activities based on their importance, parametric uncertainty, and contribution to network complexity. The importance of activities is determined by structural path analysis—which then guides the construction of life cycle models based on uncertainty and complexity indicators. Information about uncertainty is from the available life cycle inventory; complexity is quantified by cost or granularity. The life cycle model is developed in a hierarchical manner by adding the most important activities until error requirements are satisfied or network complexity exceeds user-specified constraints.
Results and DiscussionThe framework is applied to an illustrative example for building a hybrid LCA model. Since this is a constructed example, the results can be compared with the actual impact, to validate the approach. This application demonstrates how the algorithm sequentially develops a life cycle model of acceptable uncertainty and network complexity. Challenges in applying this framework to practical problems are discussed.
ConclusionThe presented algorithm designs system boundaries between scales of hybrid LCA models, includes or omits activities from the system based on path analysis of environmental impact contribution at upstream network nodes, and provides model quality indicators that permit comparison between different LCA models.
相似文献Purpose
Sustainability assessments of buildings using the life cycle approach have become more and more common. This includes the assessment of the environmental performance of buildings. However, the influence of the construction products used for the fabric, the finishing, and the technical building equipment of buildings has hardly been described in literature. For this reason, we evaluated the influence of the technical building equipment and its impact on the environment for different residential buildings.Materials and methods
Five residential buildings were evaluated by applying the methodology of life cycle assessment (LCA) (ISO14040) expressed using quantitative assessment categories according to prEN15978.Results and discussion
Results show that the optimization of energy performance has already reached a high level in Austria, so that the overall potential for possible improvements is quite low. Especially in low-energy and passive?Chouse-standard residential buildings, the limits for energy optimization in the use phase have mostly been achieved. In contrast to this, the integrated LCA (iLCA) findings attribute a high optimization potential to the construction products used for the technical building equipment as well as to the building fabric and finishing. Additionally, the passive house shows the lowest contribution of the technical building equipment on the overall LCA results.Conclusions
The iLCA findings suggest that it is recommended to include the technical building equipment for future assessments of the environmental performance of buildings. It is also suggested to use a broad number of environmental indicators for building LCA. 相似文献California is the largest US producer of processing tomatoes, generating 96% of all domestic production and nearly 30% of global supply. Processing tomatoes are mostly processed into diced and paste products. Consumers and actors along their supply chains are increasingly interested in understanding their environmental burdens and identifying opportunities for improvements. This study applies life cycle assessment (LCA) to California diced and paste products over a 10-year timeframe to characterize current impacts and historical trends.
MethodsThe LCA considers a scope from cradle-to-processing facility gate and accords with relevant Product Category Rules as published by the International EPD® System. Extensive primary data were collected for tomato cultivation for the years 2005 and 2015, and from processing facilities for 2005, 2010, and 2015 to understand the effects of evolving practices and technologies. We estimate crop and regional specific nitrous oxide and nitrate leaching emissions using a biogeochemical model, and the USES-LCA model is used to determine potential impacts from pesticide application. A suite of impact assessment categories is included based on the CML method (only global warming potential and freshwater consumption values are in the abstract).
Results and discussionThe 2015 results of the study indicate that diced tomatoes are responsible for 0.16 kg CO2e and 71 L of freshwater per kg, and paste is responsible for 0.83 kg CO2e and 328 L of freshwater per kg. The main opportunities for improvement include natural gas use in the greenhouse phase, energy for irrigation pumping and fertilizer type in the cultivation phase, and natural gas and electricity use in the facility processing phase. These hotspots are consistent with studies of processing tomato in other parts of the world. Evaluating trends over time showed that technological improvements in the industry had reduced life cycle impacts; for example, global warming potential decreased by 12% for paste and 26% for diced products between 2005 and 2015.
ConclusionsTrends over time show increasing efficiency at the cultivation and processing facility stages that have led to reductions in all impact categories evaluated. However, additional opportunities exist beyond efficiency improvements. Fertilizer and pesticide choice are potential opportunities for further reducing impacts. Also, the introduction of renewables in each phase of the supply chain (solar-powered irrigation pumps and onsite solar energy generation for facilities) could reduce the overall supply chain GWP100 impacts by 9–10%.
相似文献Purpose
This paper uses a dynamic life cycle assessment (DLCA) approach and illustrates the potential importance of the method using a simplified case study of an institutional building. Previous life cycle assessment (LCA) studies have consistently found that energy consumption in the use phase of a building is dominant in most environmental impact categories. Due to the long life span of buildings and potential for changes in usage patterns over time, a shift toward DLCA has been suggested.Methods
We define DLCA as an approach to LCA which explicitly incorporates dynamic process modeling in the context of temporal and spatial variations in the surrounding industrial and environmental systems. A simplified mathematical model is used to incorporate dynamic information from the case study building, temporally explicit sources of life cycle inventory data and temporally explicit life cycle impact assessment characterization factors, where available. The DLCA model was evaluated for the historical and projected future environmental impacts of an existing institutional building, with additional scenario development for sensitivity and uncertainty analysis of future impacts.Results and discussion
Results showed that overall life cycle impacts varied greatly in some categories when compared to static LCA results, generated from the temporal perspective of either the building's initial construction or its recent renovation. From the initial construction perspective, impacts in categories related to criteria air pollutants were reduced by more than 50 % when compared to a static LCA, even though nonrenewable energy use increased by 15 %. Pollution controls were a major reason for these reductions. In the future scenario analysis, the baseline DLCA scenario showed a decrease in all impact categories compared with the static LCA. The outer bounds of the sensitivity analysis varied from slightly higher to strongly lower than the static results, indicating the general robustness of the decline across the scenarios.Conclusions
These findings support the use of dynamic modeling in life cycle assessment to increase the relevance of results. In some cases, decision making related to building design and operations may be affected by considering the interaction of temporally explicit information in multiple steps of the LCA. The DLCA results suggest that in some cases, changes during a building's lifetime can influence the LCA results to a greater degree than the material and construction phases. Adapting LCA to a more dynamic approach may increase the usefulness of the method in assessing the performance of buildings and other complex systems in the built environment. 相似文献Purpose
The purpose of this study was to evaluate the environmental impacts linked to fish extraction on a temporal basis, in order to analyze the effect that stock abundance variations may have on reporting environmental burdens. Inventory data for the North-East Atlantic Mackerel (NEAM) fishing season were collected over an 8-year period and used to carry out a life cycle assessment (LCA). The selected fishery corresponds to the Basque coastal purse seining fleet. 相似文献Cotton yarns spun from natural fibers are widely used in the apparel industry. Most of waste cotton goods are now disposed by incineration or landfill, which brings resource and environmental challenges to the society. Using the waste cotton to spin yarns is an alternative way to forward a more sustainable future. In this research, two scenarios for the environmental impacts of yarns spun from corresponding fibers are investigated, including recycled cotton fibers and virgin cotton fibers.
MethodsThe life cycle assessment (LCA) has been conducted according to the collected data from on-site investigation of typical production factories. The life cycle for the recycled cotton yarn production is divided into five stages, i.e., raw material acquisition, transportation, breaking, mixing, and spinning. The life cycle of virgin cotton yarn production is been divided into four stages, i.e., raw material acquisition, transportation, mixing, and spinning. The functional unit is 1000 kg produced yarns which are used for weaving into the fabrics. Notable impacts on climate change, fossil depletion, water depletion, and human toxicity were observed.
ResultsThe life cycle impact assessment (LCIA) results show that environmental impacts of recycled cotton yarns are far less than those of virgin cotton yarns, except for climate change and water depletion. The reason is that the land occupation and irrigation water have great impact on environmental impacts of cotton cultivation. In spinning, the electricity is the key factor whose environmental impacts account for the most in the virgin cotton yarn scenario, while the electricity and water consumptions are the key factors for the recycled cotton yarn scenario in the life cycle of yarn production. The sensitivity analysis indicates that improving energy efficiency can significantly reduce environmental burdens for both the two scenarios. The uncertainty distribution of water depletion, human toxicity, fossil depletion, and climate change of the two scenarios were determined with a 90% confidence interval.
ConclusionsThe LCIA results reveal recycled cotton yarn is a viable alternative to relieve resource and environmental pressure. About 0.5 ha of agricultural land can be saved, 6600 kg CO2 eq can be reduced, and 2783 m3 irrigation water can be saved by using 1000 kg of the recycled cotton yarns. It can be concluded that the recycled cotton fibers can be served as a substitute for virgin cotton fibers to reduce agricultural land and avoid environmental impacts generated from the cotton planting.
相似文献