The Impact of Last-Mile Delivery Fleet Electrification on Emissions, Dispersion, and Health: An Environmental Justice Analysis Based on Dallas County, Texas

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

sustainability-3492352

Title:  Fleet Electrification in Last-mile Deliveries and Sustainable Community Health Impact: A Case Study in Dallas County, Texas

Authors:  Jaesik Choi and Kate Hyun

This study addresses the environmental and health impacts of emissions from last-mile delivery trucks. The authors use a comprehensive methodology to assess the health impacts of these emissions and evaluate the potential benefits of fleet electrification in Dallas County, Texas. Their results show that electrifying 30% of the fleet could prevent up to 70 deaths annually, and that lower-income and minority communities are more affected by higher emissions from last-mile delivery trucks. However, it is not clearly emphasized why these communities are more affected by delivery pollution—do they shop online more frequently, or do they live near busy traffic arteries?

The manuscript style is sometimes unclear. Additionally, numerous assumptions used in the methodology lead to notable limitations in the obtained data and may suggest a lack of objectivity in the findings.

I recommend the manuscript for publication after minor editing, corrections, and the inclusion of more information. I suggest the authors further address the following issues:

The authors did not specify clearly the exact dates (from - to) for the study in Dallas, Tx.

Lines 10-12:  “Despite small amounts from the tailpipe of delivery trucks, fine particulate matter is a significant source that degrades the health quality of the residents in the community.” This is a strong statement, and perhaps exaggerated in regards to delivery trucks only. Delivery trucks contribute to the overall pollution but are not a significant source of pollution.   

Lines 12-13:  “ Addressing the environmental impact of last-mile deliveries is critical to achieving sustainability goals because air pollution mitigation can reduce mortalities.” This is perhaps exaggerated, instead of “critical” recommend “desired in improving”.

Lines:  13-16:  Please consider:  “This study employs a comprehensive methodology to measure the health impact of fine particulate matter from last-mile delivery trucks and the effects of their electrification. It uses a three-tiered modeling approach, including emissions measurement, exposure level evaluation, and health impact assessment.”

Lines 20-21:  does it mean that poorer people buy more online (consume more) than people from richer communities? 

Line 45:  “amongst these materials…”, consider “amongst these pollutants….”.

Lines 47-49:  “A previous study [8] showed that last-mile delivery emissions account for 4.5% of total emissions generated in an overall supply chain process.” Comment: [8] is not a study, need to rephrase. 

Line 62:  “A few studies investigated the health impacts of …”, please consider “A few studies investigated the health and economic impacts of …” 

Line 79:  “…are particularly vulnerable because their residential places are concentrated along …”, Please consider “…are particularly vulnerable because their residential places can often be concentrated along…”

Lines 80-83:  English mistakes. Also, the statement is incomplete, need to explain why higher (e.g. due to higher traffic or multiple factors)?

Line 89:  “the amount of emissions with fleet electrification”, please consider “the amount of emissions with diverse fleet electrification”, otherwise a reader can consider 100% electrification of the fleet.

Line 251:  “in Figure 5,”, did you mean Figure 6?

Lines 307-308:  “Notably, households with a lower median household income are likely to be exposed to more emissions than households with a higher income.”, the authors need to explain why they think it happens.

Comments on the Quality of English Language

The manuscript style is sometimes unclear; it could be improved. 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This study focuses on the impact of electrification of last-mile delivery trucks on community health, closely aligning with the rapidly developing reality of e-commerce, and has significant implications for public health and environmental justice. By integrating emission models (MOVES-Matrix), dispersion models (RLINE), and health impact assessment tools (BenMAP-CE), a complete analytical chain from emission sources to health outcomes has been constructed, with strong methodological innovation. The case study design is reasonable, with high data transparency, especially in the analysis of community equity, where the K-means clustering method was introduced, revealing socioeconomic differences in PM2.5 exposure. However, some data assumptions and model limitations need further validation, and the operability of policy recommendations needs to be strengthened. Modifications are required for the following issues.

1. In order to accurately convey the academic contributions and social value of the research, while enhancing its appeal to target readers (such as policymakers, public health scholars), it is recommended that the title be changed to: The Impact of Last Mile Delivery Fleet Electrification on Health Equity: An Environmental Justice Analysis Based on Dallas County, Texas.

2. The selected keywords overly rely on tool names, have broad terminology, and lack key themes. It is suggested that the keywords be changed to: Fleet electrification; PM2.5 emissions; Environmental justice; Health disparities; Last-mile delivery; Air pollution modeling.

3. In the introduction section, the literature lacks timeliness, with most documents dating from 2015-2020, and there is a lack of key research from the past three years (2021-2024) .

4. In the research methodology section, the sampling rate of Streetlight, assuming a 10% sampling rate represents the overall traffic demand, but its stability across different areas (such as urban center vs. suburb) has not been verified, which may introduce bias.

5. Spatial resolution difference issue, MOVES-Matrix may output higher resolution data, while RLINE uses a 500-meter grid, the downscaling method needs to be explained.

6. Health indicators are singular, focusing only on mortality rates, and do not encompass the economic burden of non-fatal diseases, underestimating health benefits.

7. Figure 3 (PM2.5 Emission Heatmap) uses an adjacent red gradient; it is recommended to switch to a colorblind-friendly color palette (such as blue-yellow-red).

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

The article's topic seems interesting. The assessment of air quality and the impact on community health in connection with the development of e-shopping at the level of the selected region was carried out in a comprehensive manner—a three-level approach.

According to the reviewer:

1. The introduction could be expanded to include newer studies on the discussed topic.
2. The methods should include more detailed information on data sources, model assumptions, and validation procedures.
3. General traffic data are forecasted based on data from 2019. They were referred to 2024 based on the established indicator. This approach may not accurately reflect the actual data in 2024, considering the impact of the pandemic on travel behavior—this could be justified.
4. All graphical studies require correction - Figures 2, 3, 4 - why does an oval of different sizes surround the highlighted zones (A, B, C, D, E)? Is this a form of presentation defining their size? In addition, in the subsequent figures, the description disappears. Figures 6 and 7 are unfinished – I understand that the analysis results were plotted on the map, which obscured the background – in the reviewer’s opinion, this presentation was not very well done.
5. The results present the most important conclusions from the study. It is suggested that the article be expanded with a Discussion, in which the authors include a more detailed interpretation of the results and relate them to the scientific literature.

To sum up, the article's subject has potential, but it requires refinement. Perhaps it would be appropriate to deal only with suspended dust emitted from car exhaust pipes and its impact on the environmental conditions of the research area. Adding the mortality rate of residents to these analyses seems unnecessary and not very supported by the results. It can only be a kind of interjection, a supposition, and not the result of the studies performed.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The revisions have comprehensively addressed the comments from reviewers, thereby enhancing the manuscript's precision and influence. The incorporation of emissions modeling, health equity, and policy relevance has notably advanced the research in sustainable logistics and environmental justice. The paper is now prepared for publication.

Reviewer 3 Report

Comments and Suggestions for Authors

The work considers the reviewer's suggested changes, and the authors addressed the doubts noted in the review. Thank you very much. In the future, please avoid starting sentences with the word "this" and try to prevent the personal form "we".