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Year: 2025

Exploratory Data Analysis of a North American Whole Building Life Cycle Assessment datasets

Shen, Y., Benke, B., Ashtiani, M., Huang, M., & Simonen, K. (2025). Exploratory Data Analysis of a North American Whole Building Life Cycle Assessment datasets. Building and Environment, 286, Article 113655. https://doi.org/10.1016/j.buildenv.2025.113655

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Abstract

The building construction sector is a major contributor to global greenhouse gas emissions, with embodied carbon—the emissions from material production, use, and disposal—forming a significant portion. While whole building life cycle assessment (WBLCA) quantifies such impacts, detailed statistical analysis for interpretation of WBLCA data remains underutilized. This study addresses the gap by introducing a systematic exploratory data analysis (EDA) framework applied to a harmonized and high-resolution dataset of 244 real-world North American buildings. The core steps in the EDA framework include distinguishing attributes, univariate analysis, bivariate analysis, and feature engineering. These steps address the different data challenges, such as high dimensionality, mixed attribute types, missing values, outliers, and multivariate relationships through the evaluation of robust selections of statistical methods in EDA. Bivariate analysis (e.g., mutual information, one-way ANOVA, post-hoc analysis, and two-way ANOVA) and feature engineering methods quantified the correlation and differences in pairwise and global relationships. Embodied carbon intensity weakly correlated with most meta-features, while materials and building use emerged as the most influential factors. Given that the dataset is uniquely comprehensive and disaggregated, a more nuanced and detailed understanding of environmental impact patterns and relationships is possible. This research demonstrates that following the systematic EDA framework provides a well-defined process to address the database challenges. Its integration into WBLCA dataset evaluation enhances interpretation and supports informed decision-making for low-carbon building design and decarbonization strategies that a conventional simplified analysis would miss. Moreover, it helps to build the insights necessary for advanced analysis and predictive modeling.

Keywords

Life cycle assessment; Whole building life cycle assessment; Embodied carbon; Data analysis; Exploratory data analysis; Statistical analysis; Building decarbonization

BRE-X Emissions Database for End-of-Life Scenarios of Selective Building Construction Materials to Enable Circular Economy in Construction

Muthumanickam, N. K., Atnoorkar, S., Goetsch, H., Deru, M., Palmeri, J., Ashtiani, M., Hasik, V., & Farnetani, M. (2025). BRE‐X Emissions Database for End‐of‐Life Scenarios of Selective Building Construction Materials to Enable Circular Economy in Construction. Journal of Advanced Manufacturing and Processing, 7(3). https://doi.org/10.1002/amp2.70018

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Abstract

In the United States, construction and demolition debris predominately end up in landfills with minimal end-of-life Re-X (recover, recycle, reuse, etc.) scenarios, resulting in large environmental impacts and lost opportunities for material recovery. Except for concrete and metals, which seem to have a few well-defined end-of-life pathways, there seems to be a lack of well-documented end-of-life scenarios for other construction materials, let alone their emissions data. Hence, there is a need for documented end-of-life Re-X scenarios and end-of-life data of more building materials to motivate widespread use of Re-X strategies in building design. This paper outlines the efforts of the National Renewable Energy Laboratory, Carbon Leadership Forum, Building Transparency, and Skidmore, Owings & Merrill to (a) create an open-access BRE-X (Building Re-X) end-of-life emissions database consisting of greenhouse gas emissions data associated with various end-of-life scenarios for a select list of high-impact building construction materials, and (b) integrate the BRE-X end-of-life emissions database with CAD/BIM/LCA tools for evaluating various end-of-life scenarios. The paper also presents a few existing life cycle inventory databases that contain sparse amounts of end-of-life data for a few construction materials and their limitations in terms of scaling and data consolidation. Finally, a sample of how the collected data can be ingested into whole-building LCA tools using open data formats and a public access link to the BRE-X end-of-life emissions database is also included.

A Harmonized Dataset of High-Resolution Embodied Life Cycle Assessment Results for Buildings in North America

Benke, B., Chafart, M., Shen, Y., Ashtiani, M., Carlisle, S., & Simonen, K. (2025). A Harmonized Dataset of High-Resolution Embodied Life Cycle Assessment Results for Buildings in North America. Scientific Data, 12(1), Article 1085. https://doi.org/10.1038/s41597-025-05216-0

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Abstract

Building design practitioners are increasingly using life cycle assessment (LCA) to assess the environmental impacts of their buildings. However, industry-generated LCA results are rarely compiled into comparable datasets and rarely made public. Thus, harmonized and open-access datasets of building LCA results are limited, particularly in North America. Here we present a novel high-resolution dataset of building design characteristics, life cycle inventories, and environmental impact assessment results for 292 building projects in the United States and Canada. The dataset contains harmonized and non-aggregated LCA model results across life cycle stages, building elements, and building materials to enable detailed analysis, comparisons, and data reuse. It includes over 90 building design and LCA features to assess distributions and trends of material use and environmental impacts. Uniquely, the data were crowd-sourced from designers conducting LCAs of real-world building projects. This dataset fills critical gaps for the building industry, research, and policy communities, enabling them to analyze and compare the impacts of buildings, test or set performance targets, and motivate sustainable design and construction practices.

A novel whole-life carbon assessment of thirty buildings in California

Shen, Y., Benke, B., Roberts, M., Carlisle, S., Chafart, M., & Simonen, K. (2025). A novel whole-life carbon assessment of thirty buildings in California. Journal of Building Engineering, 110, Article 113074. https://doi.org/10.1016/j.jobe.2025.113074

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Abstract

Reducing whole-life carbon emissions from buildings is essential to achieving global climate targets. While many studies exist, few focuses on whole-life carbon assessment at the U.S. state level, such as California, which has strict decarbonization goals and a rapidly evolving policy landscape. To address this gap, we introduce a novel framework encompassing data collection, preparation, carbon calculation, whole-life assessment, and methodological variation analysis—based on data from industry professionals for thirty real buildings in California. To address inconsistency issues among data, a structured data entry template and user guide were developed and data preprocessing and alignment methods were proposed. Finally, the whole-life carbon and temporal relationship of embodied and operational carbon were quantified. Whole-life carbon intensity (WLCI) ranged from 232-2230 kg CO2e/m2, with embodied carbon intensity (ECI) between 192 and 685 kg CO2e/m2 and operational carbon intensity (OCI) from 13 to 1710 kg CO2e/m2. Median values for ECI, OCI, and WLCI were 385, 228, and 734 kg CO2e/m2, respectively. This highlights that embodied carbon constituted a substantial share of total emissions, often exceeding operational carbon, which varied more due to energy sources. The analysis showed modules A1-A3, structural systems, and concrete/metals as major contributors to embodied carbon, with interiors also adding significant emissions. Methodological variations in whole-life carbon assessment were noted, particularly concerning grid decarbonization scenarios, floor area normalization, and energy data sources. Although developed for California, the methods and framework for whole-life carbon assessment are broadly applicable to global contexts.

Keywords

Whole-life carbon assessment; Operational carbon; Embodied carbon; Building life cycle assessment; Data collection; Decarbonization

What matters the most in designing low-carbon buildings in Canada? Exploring the tradeoff between embodied and operational carbon in early stage design

Torabi, M., Simonen, K., & Evins, R. (2025). What matters the most in designing low-carbon buildings in Canada? Exploring the tradeoff between embodied and operational carbon in early stage design. Energy and Buildings, 334, Article 115482. https://doi.org/10.1016/j.enbuild.2025.115482

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Abstract

Reducing global greenhouse gas emissions is a crucial sustainability objective around the world. The ambitious sustainability targets that have been defined for the building sector can only be achieved through carbon-sensitive design from the beginning. Multiple design parameters, their impacts on building performance, along with embodied and operational carbon tradeoffs makes it difficult for architects to compare design alternatives in the uncertain context of early-stage design. Tools and methods often focus more on either operating efficiency or material selection rather than assisting architects in making holistic carbon-sensitive design decisions.
In this research, a design-compatible methodology for low-carbon buildings was developed by using design exploration methods and parametric calculations of whole-life carbon emissions. The model was run for seven Canadian cities, resulting in over 20,000 design scenarios to capture a broad range of potential solutions. The study investigates the most influential design parameters in relation to the varying carbon intensity of local grid electricity. The results show that despite the significant impact of climate, local grid carbon emission intensity plays the most crucial role in defining building design priorities in order to optimize for total life carbon impacts. The results also indicate that mechanical and structural systems play a significant role in building carbon footprint. The results also show that in cities with high grid carbon factors, optimizing window-to-wall ratio, level of insulation and geometry can contribute the most to reducing carbon footprint. Conversely, in cities with low local grid carbon emission intensity, structural material and mechanical systems selection are highly impactful and all other factors play a marginal role.

Keywords

Life Cycle Assessment; Embodied Carbon; Operational Carbon; Building Carbon Footprint; Early-Stage LCA; Design parameters; Design Space Exploration; Sensitivity Analysis

From tweets to energy trends (TwEn2): social sensing–informed urban building energy modeling

Narjes Abbasabadi, & Mehdi Ashayeri. (2025). From tweets to energy trends (TwEn2): social sensing–informed urban building energy modeling. Frontiers in Energy Research, 13. https://doi.org/10.3389/fenrg.2025.1688348

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Abstract

This study builds on our previous research, “From Tweets to Energy Trends (TwEn)” framework, which demonstrated the potential of social media interactions to inform urban energy predictions through a data-driven approach. Building on this foundation, we introduce TwEn2, a hybrid data-driven and physics-based modeling framework that advances the framework by enabling building-level analysis of urban-scale energy use with greater spatial specificity and enhanced applicability for urban building energy modeling (UBEM). The framework integrates geo-tagged social sensing data from the X platform with the U.S. Department of Energy’s prototype building models—focusing on mid-sized and large multifamily residential buildings across New York City’s boroughs—and benchmarking records. Tweet activity within building footprints is analyzed as a proxy for occupant presence and behavior, allowing assessment of correlations between human social dynamics and both measured and simulated monthly energy use across electricity, natural gas, and total energy consumption. By incorporating heigh fidelity social-sensing-data into physics-based simulations, TwEn2 improves predictive accuracy and enables UBEM informed by human activity patterns, validated against empirical benchmarking data. This framework provides a scalable, generalizable tool for urban energy modeling, planning, resilience and sustainability strategies, demonstrating the potential of social media as a real-time indicator of occupant dynamics to support informed energy management in cities.

Unveiling post-pandemic commute choices amidst the rise of telework

Ashour, L., & Shen, Q. (2025). Unveiling post-pandemic commute choices amidst the rise of telework. Transportation Research. Part D, Transport and Environment, 149, Article 105068. https://doi.org/10.1016/j.trd.2025.105068

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Abstract

The post-pandemic “new normal” is characterized by increased adoption of telework and a decline in transit use, with a growing uncertainty about the long-term effects of these trends. This study investigates the impact of telework adoption on commute mode choice and the factors influencing individual preferences in the new normal, using data from the 2022 Seattle Commute Survey, capturing mode choice on each day in a typical workweek, providing a mixture of modes and the frequency of use for each respondent. Using the Multiple Discrete-Continuous Extreme Value (MDCEV), the study provides timely insights into the factors influencing commute mode choice, highlighting the significant influence of sociodemographic, job-related, and built environment characteristics on mode choice and the nuanced difference between modes, raising concerns about potential inequities in the new normal. The findings highlight the need to prioritize access to public transit, adapt transportation infrastructure to telework, and address rising inequities.

Road User Fees in the USA: Theory, Research, and Practice

Chen, P., Shen, Q., & Boardman, S. (2025). Road User Fees in the USA: Theory, Research, and Practice. Journal of Planning Literature. https://doi.org/10.1177/08854122251385953

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Abstract

This paper examines the theory, research, and practice of road user charge (RUC) in the USA. It explores neoclassical, behavioral, and institutional economic perspectives to assess RUC's environmental benefits, data privacy, public acceptance, and equity implications. A synthesis of recent studies highlights RUC's financial, environmental, social, and urban transportation system impacts. The examination of state and regional initiatives presents several critical challenges associated with the implementation of RUC systems. This study provides a nuanced understanding of RUC's potential and barriers as a sustainable transportation funding mechanism and offers insights into future research and policy development.

An outlook on ride-sourcing price changes: Implications for future transit agency-TNC partnerships

Ashour, L., & Shen, Q. (2025). An outlook on ride-sourcing price changes: Implications for future transit agency-TNC partnerships. Transport Policy, 173, Article 103790. https://doi.org/10.1016/j.tranpol.2025.103790

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Abstract

Ride-sourcing trip prices charged by transportation network companies (TNCs) have increased significantly compared to before the pandemic, causing concerns about the effectiveness of existing and planned transit agency-TNC partnerships. This paper explores three scenarios of future TNC price changes: (1) price trend extension using forecasting models, (2) price increase in response to local policy changes, and (3) TNC/taxi price convergence due to increased competition. We then investigate the impact of TNC price change on the prospect of transit agency-TNC partnerships, using a case study in the Seattle region. For the first scenario, we employ two time-series models, namely ARIMA and PROPHET, to forecast price changes within the next three years (Oct 2022–Oct 2025) using publicly available Chicago TNC trip data. The results show that TNC's daily average price would reach $3.23 per mile, increasing by 40 % from 2019 average rates. For the second scenario, we track significant policies that directly impacted TNC prices in Seattle and incorporate reported price increases. The resulting estimations indicate that TNC prices would increase by an extra 25 % in response to changes in the minimum wage law. For the third scenario, we use publicly available taxi trip data of the city of Chicago and forecast future taxi prices by estimating time-series models comparable to those for TNC prices. The analysis suggests that due to increased competition, TNC and taxi prices are converging and that the average TNC fare per mile could add another 50 % to the forecasted price if TNC and taxi prices become similar in the upcoming three years. These price changes are shown to have a considerable negative impact on the expected cost-effectiveness of transit agency-TNC partnerships. Although such partnerships could still provide many benefits, transportation planners and policymakers should carefully examine the implications of TNC price increases resulting from changing market and policy environments.