Comparative environmental assessment of construction materials in climate action projects

Currently, there are no life cycle impact data available on the construction of road infrastructure in Brazil. This study aimed to determine several environmental impacts associated with the construction of an asphalt-paved highway in Brazil using the life cycle assessment approach and road construction data available from two Brazilian highways. The results from this study can potentially raise awareness to the importance of life cycle thinking in road construction in Brazil. The processes considered within the asphalt road pavement product system were extraction and processing of sand, gravel, and pitch; transportation of these inputs; and machinery use and operation, including direct and indirect emissions, raw materials, and electricity/fuel. Inventories available in Ecoinvent were used, and processes relevant to the Brazilian scenario were selected, with modifications made when necessary. The ReCiPe method was used to calculate the impacts, and for each category a second method was used to verify the results. The impact categories analyzed were global warming potential (GWP), terrestrial acidification potential (TAP), ozone depletion potential (ODP), freshwater eutrophication (FWEP), marine eutrophication (MEP), and freshwater ecotoxicity (FWECP). In addition, an alternative scenario was considered by substituting diesel with biodiesel in the transportation trucks. Gravel production was the main contributor to TAP (56% based on ReCiPe) and MEP (62%) categories. It was also a significant contributor to the GWP (16%), FWEP (25%), and FWECP (33%) categories. Transport of raw materials was the most impactful process in the GWP (58%), FWEP (55%), and FWECP (52%) categories. Pitch production was the major contributor to the ODP category (57%). The impact from sand production was negligible for all categories. Machinery operation had a small contribution in all impact categories (less than 14%). The different assessment methods used for each category indicated similar percent contributions for all processes considered (gravel, sand, pitch, transport, and machinery). Substitution of diesel with biodiesel caused an increase in the total impact for all categories, except for ODP. Gravel and pitch production, as well as raw material transport, were the most impactful processes in road construction. Therefore, strategies to reduce the impacts of road construction projects should focus on these three processes. In particular, investigation of the environmental impact, using a life cycle approach, of substituting gravel and pitch with alternative or recycled materials should be carried out for the Brazilian context.

Background, aim and scope Regional specificities are a key factor when analyzing the environmental impact of a biofuel pathway through a life cycle assessment (LCA). Due to different energy mixes, transport distances, agricultural practices and land use changes, results can significantly vary from one country to another. The Republic of Argentina is the first exporter of soybean oil and meal and the third largest soybean producer in the world, and therefore, soybean-based biodiesel production is expected to significantly increase in the near future, mostly for exportation. Moreover, Argentinean biodiesel producers will need to evaluate the environmental performances of their product in order to comply with sustainability criteria being developed. However, because of regional specificities, the environmental performances of this biofuel pathway can be expected to be different from those obtained for other countries and feedstocks previously studied. This work aims at analyzing the environmental impact of soybean-based biodiesel production in Argentina for export. The relevant impact categories account for the primary non-renewable energy consumption (CED), the global warming potential (GWP), the eutrophication potential (EP), the acidification potential (AP), the terrestrial ecotoxicity (TE), the aquatic ecotoxicity (AE), the human toxicity (HT) and land use competition (LU). The paper tackles the feedstock and country specificities in biodiesel production by comparing the results of soybean-based biodiesel in Argentina with other reference cases. Emphasis is put on explaining the factors that contribute most to the final results and the regional specificities that lead to different results for each biodiesel pathway.

A comparative life cycle assessment (LCA) on two types of phthalate plasticizer, DOP( Di-Octyl Phthalate or DEHP (Di-Ethyl Phthalate)) and DINP (Di-Isononyl Phthalate), is conducted in this study. The reference flow is defined as DOP(0.346 kg) and DINP(0.360 kg), the amount of required to produce PVC 1kg, respectively. The life cycle impact assessment is carried out for 6 impact categories such as POCP (Photochemical Oxidant Cretion Potential), ADP (Aboitic resource Depletion Potential), AP (Acidification Potential), EP (Eutrophication Potential), GWP (Global Warming Potential) and ODP (Ozone Depletion Potential). Then, the characterization results (indicator profile) are normalized by using the normalization references developed by the Ministry of Trade, Industry and Energy (MOTIE). The normalization results show that both DOP and DINP have relatively significant effect of ADP and GWP when the normalized value of DINP are slightly larger than these of DOP. On the other hand, DOP shows larger impacts than DINP for POCP, EP and ODP by 176.9%, 109.9%, 219.4%, respectively.

Background:The Life Cycle Initiative, hosted at the United Nations Environment Programme, selected human toxicity impacts from exposure to chemical substances as an impact category that requires global guidance to overcome current assessment challenges. The initiative leadership established the Human Toxicity Task Force to develop guidance on assessing human exposure and toxicity impacts. Based on input gathered at three workshops addressing the main current scientific challenges and questions, the task force built a roadmap for advancing human toxicity characterization, primarily for use in life cycle impact assessment (LCIA).Objectives:The present paper aims at reporting on the outcomes of the task force workshops along with interpretation of how these outcomes will impact the practice and reliability of toxicity characterization. The task force thereby focuses on two major issues that emerged from the workshops, namely considering near-field exposures and improving dose–response modeling.Discussion:The task force recommended approaches to improve the assessment of human exposure, including capturing missing exposure settings and human receptor pathways by coupling additional fate and exposure processes in consumer and occupational environments (near field) with existing processes in outdoor environments (far field). To quantify overall aggregate exposure, the task force suggested that environments be coupled using a consistent set of quantified chemical mass fractions transferred among environmental compartments. With respect to dose–response, the task force was concerned about the way LCIA currently characterizes human toxicity effects, and discussed several potential solutions. A specific concern is the use of a (linear) dose–response extrapolation to zero. Another concern addresses the challenge of identifying a metric for human toxicity impacts that is aligned with the spatiotemporal resolution of present LCIA methodology, yet is adequate to indicate health impact potential.Conclusions:Further research efforts are required based on our proposed set of recommendations for improving the characterization of human exposure and toxicity impacts in LCIA and other comparative assessment frameworks. https://doi.org/10.1289/EHP3871

This paper focused on the environmental performance of a nearly zero-energy wood-based educational building (NZEB-W) via the life cycle impact assessment (LCIA). It identifies the environmental impacts of construction materials and operational energy demands of the NZEB-W and compares them using the SimaPro 8 software with the IMPACT 2002+ method. The LCIA results from NZEB-W show that the overall environmental impact of construction materials (98.9 Pt) and 45 years operational energy demands (98.6 Pt) will be at the same level. Its overall environmental impact 197.75 Pt for 45 years is relatively small. NZEB-W has the greatest impact on the environment in the category of damage respiratory inorganics (34.5%), 419 kg PM2.5 eq from construction materials, and 271 kg PM2.5 eq from operational energy for 45 years; follows global warming (31.7%), 1.98 × 105 kg CO2 eq from construction materials, and 4.23 × 105 kg CO2 eq from operational energy for 45 years; and non-renewable energy (21.8%), 2.82 × 106 MJ primary from construction materials, and 3.73 × 106 MJ primary from operational energy for 45 years. As this environmental assessment shows, the material composition of construction materials compared to the energy consumption in the use phase is an essential element for understanding the life cycle impact of buildings.

Life cycle assessment of a geothermal combined heat and power plant based on high temperature utilization

Biofuels are important sources of energy especially in the face of the global climate problem and threats. This comprehensive review paper brings forth a critical analysis of the role of biofuels as a potential solution to energy crises, with a specific focus on South Africa. Leveraging the methodologies of Life Cycle Assessment (LCA) and Life Cycle Impact Assessment (LCIA), we systematically delve into the environmental impact of biofuel production and its implications on policy decisions. The manuscript encompasses an exhaustive review of selected academic studies which primarily explore the generation of electricity via biofuel technologies. We investigate the functional units employed in the respective studies, providing an illustrative overview of their variance, and elucidating their significance in shaping the outcomes of these assessments. The study also evaluates a broad spectrum of environmental impact categories, unraveling a complex interplay of diverse factors and ascertaining which biofuel has the least environmental impact. The role of biofuels in South Africa’s energy transition are explored and recommendations for a more standardized and comprehensive approach to future LCA studies in biofuels proposed. From our synthesis of the collected data, we identify Global Warming Potential (GWP) and Human Toxicity (HT) as predominant environmental issues that demand urgent attention. This paper culminates in a nuanced examination of the prospective role that biofuels can play in addressing South Africa’s energy crisis while cognizant of the challenges hindering the growth of its biofuel industry.

PurposeThe need to assess the sustainability attributes of the United States beef industry is underscored by its importance to food security locally and globally. A life cycle assessment (LCA) of the US beef value chain was conducted to develop baseline information on the environmental impacts of the industry includ`ing metrics of the cradle-to-farm gate (feed production, cow-calf, and feedlot operations) and post-farm gate (packing, case-ready, retail, restaurant, and consumer) segments.MethodsCattle production (cradle-to-farm gate) data were obtained using the integrated farm system model (IFSM) supported with production data from the Roman L. Hruska US Meat Animal Research Center (USMARC). Primary data for the packing and case-ready phases were obtained from packers that jointly processed nearly 60% of US beef while retail and restaurant primary data represented 8 and 6%, respectively, of each sector. Consumer data were obtained from public databases and literature. The functional unit or consumer benefit (CB) was 1 kg of consumed, boneless, edible beef. The relative environmental impacts of processes along the full beef value chain were assessed using a third party validated BASF Corporation Eco-Efficiency Analysis methodology.Results and discussionValue chain LCA results indicated that the feed and cattle production phases were the largest contributors to most environmental impact categories. Impact metrics included water emissions (7005 L diluted water eq/CB), cumulative energy demand (1110 MJ/CB), and land use (47.4 m2a eq/CB). Air emissions were acidification potential (726 g SO2 eq/CB), photochemical ozone creation potential (146.5 g C2H4 eq/CB), global warming potential (48.4 kg CO2 eq/CB), and ozone depletion potential (1686 μg CFC11 eq/CB). The remaining metrics calculated were abiotic depletion potential (10.3 mg Ag eq/CB), consumptive water use (2558 L eq/CB), and solid waste (369 g municipal waste eq/CB). Of the relative points adding up to 1 for each impact category, the feed phase contributed 0.93 to the human toxicity potential.ConclusionsThis LCA is the first of its kind for beef and has been third party verified in accordance with ISO 14040:2006a and 14044:2006b and 14045:2012 standards. An expanded nationwide study of beef cattle production is now being performed with region-specific cattle production data aimed at identifying region-level benchmarks and opportunities for further improvement in US beef sustainability.

Cement production is associated with a considerable environmental load, which needs to be fully understood before effective measures can be taken. The existing literature did not give detailed life cycle assessment (LCA) study of China and had limited potential for investigating how best available techniques (BATs) would provide a maximum benefit when they are applied in China. Japan was selected as a good example to achieve better environmental performance of cement production. We identified potentials for reducing emissions and saving energy and natural resources in Chinese cement industry through the comparative analysis. This paper follows the principal of Life Cycle Assessment and International Reference Life Cycle Data System (ILCD). The functional units are “1 t of portland cement” and with 42.5 MPa of strength grade. The input (limestone, sandstone, ferrous tailings, coal, and electricity) and output (CO2 from limestone decomposition and coal combustion, NOx, PM, and SO2) of cement manufacturing were calculated by use of on-site measurements, calculation by estimated coefficients, and derivation by mass and heat balance principle. The direct (cement manufacturing) and indirect (electricity production) LCI are added to be total LCI results (cement production). The impact categories of global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), photochemical oxidant formation potential (POCP), and human toxicity potential (HTP) are used to calculate environmental impact. Only in GWP of cement manufacturing China has advantage. Japanese cement industry shows remarkable superiorities in the environmental impacts of AP, POCP, HTP, and EP due to advanced technologies. SO2 emissions make the corresponding AP and HTP. PM emissions result in part of HTP. The NOx emissions are the major contributors of POCP, AP, EP, and HTP in China. China emits fewer CO2 emissions (2.09 %) in cement manufacturing than Japan but finally makes higher total GWP than Japan due to more GWP of electricity generation in power stations. The waste heat recovery technology can save electricity but bring more coal use and CO2 emissions. The alternative fuel and raw materials usage and denitration and de-dust technologies can relieve the environmental load. Using the functional unit with the strength grade, the life cycle impact assessment (LCIA) results are affected. LCA study allows a clear understanding from the view of total environmental impact rather than by the gross domestic product (GDP) unit from an economic development perspective. In an LCA study, the power generation should be considered in the life cycle of cement production.

Environmental performance of Miscanthus as a fuel alternative for district heat production

Life cycle assessment (LCA) has been increasingly implemented in analyzing the environmental performance of buildings and construction projects. To assess the life cycle environmental performance, decision-makers may adopt the two life cycle impact assessment (LCIA) approaches, namely the midpoint and endpoint models. Any imprudent usage of the two approaches may affect the assessment results and thus lead to misleading findings. ReCiPe, a well-known work, includes a package of LCIA methods to provide assessments on both midpoint and endpoint levels. This study compares different potential LCIA results using the midpoint and endpoint approaches of ReCiPe based on the assessment of a commercial building in Hong Kong. This paper examines 23 materials accounting for over 99 % of the environmental impacts of all the materials consumed in commercial buildings in Hong Kong. The midpoint and endpoint results are compared at the normalization level. A commercial building in Hong Kong is further studied to provide insights as a real case study. The ranking of impact categories and the contributions from various construction materials are examined for the commercial building. Influence due to the weighting factors is discussed. Normalization results of individual impact categories of the midpoint and endpoint approaches are consistent for the selected construction materials. The difference in the two approaches can be detected when several impact categories are considered. The ranking of materials is slightly different under the two approaches. The ranking of impact categories demonstrates completely different features. In the case study of a commercial building in Hong Kong, the contributions from subprocesses are different at the midpoint and endpoint. The weighting factors can determine not only the contributions of the damage categories to the total environment, but also the value of a single score. In this research, the midpoint and endpoint approaches are compared using ReCiPe. Information is whittled down from the inventories to a single score. Midpoint results are comprehensive while endpoint results are concise. The endpoint approach which provides additional information of damage should be used as a supplementary to the midpoint model. When endpoint results are asked for, a LCIA method like ReCiPe that provides both the midpoint and endpoint analysis is recommended. This study can assist LCA designers to interpret the midpoint and endpoint results, in particular, for the assessment of commercial buildings in Hong Kong.

Construction and using of buildings for many years produce long-lasting impacts on human health and the environment. Life cycle assessment (LCA) is the rapidly evolving science of clarifying these impacts in terms of their quality, severity, and duration. LCA of three selected new family houses located in Eastern Slovakia is performed with the aim to compare them in terms of built-in materials as well as used technologies. The main goal of the analysis is to investigate and underline the foreseeable reduction rate of environmental impacts resulting from applied green materials and green technologies. LCA impact categories of global warming potential (GWP), ozone depletion potential (ODP), acidification potential (AP), eutrophication potential (EP), and photochemical ozone creation potential (POCP) are selected for this analysis. Investigated family houses are built from conventional materials, such as aerated concrete blocks, reinforced concrete, thermal insulation of silicate mineral slabs, and roofing mineral wool, as well as natural materials, such as clay, straw, wood, cellulose, and vegetation roofs. Product phase contributes greatly to the GWP for houses built of conventional materials. AP, EP, ODP, and POCP impact categories are considerable also in the product phase. Even an operational energy phase contributes a large share of the negative impact on the environment. Adoption of green design and technology in buildings, which can mitigate negative impacts on the environment, has been recognized as a key step towards global sustainable development. The main goal of this article is to make the case that green buildings are important for reducing negative effects on the environment and resources, while simultaneously enhancing positive effects throughout the building life cycle.

Urbanization causes profound changes in the hydrology of developed watersheds with many negative impacts on local, regional, and global energy and water balances, non-point sources of pollution, loss of stream/riparian structure and function, coastal and terrestrial habitats, and changes in atmospheric composition. In an effort to remedy such conditions, many researchers are trying to quantify the range and extent of ecosystem services like thermal regulation, water regulation, aquifer recharge, water quality improvement, habitat, and cultural services that can be achieved by retrofitting engineered Green Infrastructure (GI) into the urban landscape. These niche ecosystems, often funded as a means of managing urban runoff or compensating for habitat loss, typically include soil and vegetation, arranged in new configurations across formerly impervious spaces. The ability of GI to provide meaningful ecosystem services is both enabled, and constrained, by soil moisture, a key driver of ecosystem function and structure. At a particular site, a soil moisture field emerges as the product of soil-water-climate and vegetation interactions. This field then mediates the local water and energy balance, constrains photosynthesis, supports biota, and controls the redox state. Though billions of dollars are currently being spent on GI, very few researchers have been able to document GI's ability to actually provide ecosystem functions and services in different biophysical and climatic regimes. Such work is needed since engineered GI is fundamentally different from other green kinds spaces (e.g. agricultural plots, forests) in that the imported and/or amended soil, bacteria, and newly transplanted vegetation are both in dynamic, early states of development. This dissertation will shed light on the potential role of soil moisture in determining the ecohydrologic performance of engineered GI, a first step in studying GI's ecosystem services. Specifically, we investigate the role that design decisions can have on spatiotemporally variable soil moisture patterns, and the ecosystem services that depend on them. The research includes observations made in the laboratory and in the field, as well as modeling. It is organized into three papers, as follows: · Paper 1 analyzes several years of soil moisture data collected in two urban GI systems. Relationships between precipitation characteristics, season, and hydraulic loading ratio and soil moisture at different depths are quantified. Potential linkages between GI siting and design decisions and ecosystem services are illustrated by also computing evapotranspiration rates at the sites, speculating that site/or climate factors that lead to higher moisture content, engender greater ES associated with ET. · Paper 2 presents laboratory research conducted using a rainfall simulator to demonstrate the ecohydrological significance of GI surface treatments that buffer the impact of raindrops. This paper attempts to: a) determine if vegetation canopies found in typical GI system can protect the soil surface, and reduce crust formation; b) decreasing post-storm surface ponding, and c) increasing the infiltration of water and recharge, when compered to bare soil surfaces. This study focuses on two different scenarios: 1) bare soil and 2) soil protected by synthetic vegetation canopies. Soil moisture, the surface's penetration resistance, and physical measurements of the volume of infiltrate and runoff are made on all two surface treatments after simulated rainfall events. The results are used to develop recommendations regarding surface treatment in engineered urban GI system designs. · Paper 3 attempts to model the observations reported in the companion papers 1 and 2. Specifically, a customized soil moisture model is developed for use in simulating the spatiotemporal variation in the soil moisture regime engineered GI systems. The model is calibrated to in-situ soil moisture observations made at engineered GI sites, and then used to explore the role that decisions regarding the design, construction, operation and maintenance of these unique systems will influence their ability to provide ecosystem services. Specifically, we investigate how differences in hydraulic loading, surface treatment, and precipitation influence the potential for GI systems to yield runoff and recharge under extreme precipitation conditions.

Purpose Life Cycle Impact Assessment (LCIA) has traditionally applied characterization factors (CFs) to elementary flows in isolation, treating impacts as fixed properties of substances, regardless of where and how they occur within the life cycle product system. While recent advances have introduced regionalized LCIA methods and GIS-based spatial modeling frameworks, these remain difficult to operationalize in routine assessments and are often limited to differentiation at the elementary flow level. This paper presents a methodological advancement in LCIA: the application of CFs at the level of exchanges—the resolved biosphere and technosphere flows between processes. Methods Shifting the CF unit from elementary flows to exchanges enables CFs to reflect the full context of each exchange, including the geographic origin and destination, the identity of the emitting process and environmental recipient, and prospective, scenario-dependent parameters. The method offers a flexible, intermediate solution between traditional elementary flow-based LCIA and full spatially explicit models, supporting national and subnational regionalization without requiring high-resolution GIS integration. Results The approach is implemented in the open-source Python library edges , which extends the Brightway LCA framework to support exchange-specific and symbolic CFs. We illustrate its capabilities through four applications: 1) Regionalized LCIA, using the AWARE water scarcity method with dynamic handling of region aggregation and disaggregation; 2) Technosphere-based LCIA, via a new implementation of the GeoPolRisk indicator, which assigns CFs based on country-to-country commodity trade relationships; and scenario-sensitive prospective LCIAs, enabling alignment with climate scenarios, where CFs are defined by symbolic expressions that depend on scenario-specific variables, with application 3) focusing on global warming potential based on atmospheric gas concentration, and application 4) addressing fossil resource scarcity through dynamic fossil fuels extraction rates. Conclusions Together, these examples demonstrate how exchange-resolved LCIA expands the methodological space of impact modeling, offering a scalable, exchange-aware framework for regional, relational, and future-oriented life cycle assessments.

Life cycle impact assessment of photovoltaic power generation from crystalline silicon-based solar modules in Nigeria