Vehicle Stock Numbers and Survival Functions for On-Road Exhaust Emissions Analysis in India: 1993–2018

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Introduction:

This journal strives to provide up-to-date research on sustainability to a global audience. The decision to begin the discussion with a formula for vehicle emissions may not be immediately relevant. Additionally, the focus on a case study from India might not resonate with all readers. It would be beneficial to start with a broader theoretical framework, highlighting current research trends in key areas such as Vehicle Exhaust Emissions, Vehicle Stock, and Registered Vehicle Numbers. Including a rationale for why the Indian case study is pertinent to the field could also provide valuable context.

Furthermore, the article should clearly outline the research gaps this study intends to address before delving into the methodology. A review of previous studies within this framework, along with any challenges encountered in prior approaches, would establish a solid foundation for understanding the significance and novelty of the research. Notably, the research objectives and questions need to be clearly stated to guide the reader through the study’s aims and expected outcomes.

Methodology:

The presentation of the methodology, although supported by equations and charts, lacks a clear analytical framework. It would be beneficial for readers to understand the structure and setup of the methodology before delving into specific data such as registered vehicle stock numbers. Clarifying how the methodology is designed to address the research questions would greatly enhance comprehension and provide a stronger foundation for the subsequent analysis.

Results:

It appears that the section titled "3. Open Data Resources" is intended to present the results, but it is currently unclear what specific findings the study has produced. To improve clarity and comprehension, it would be beneficial to explicitly state the key results of the study within this section.

Additionally, concluding the results section with a concise summary would provide a cohesive overview of the findings. This would not only help in clarifying the presented data but also facilitate a smooth transition into the discussion chapter.

Discussion:

It is essential to comprehensively recapitulate the methodology used in the study. The current description in the discussion section lacks the necessary detail, particularly in demonstrating how the methodology contributes to achieving the study's objectives. Enhancing the clarity and specificity when outlining the research processes would greatly improve the reader's understanding of how the key results were attained and how challenges were addressed during the study.

Additionally, a more rigorous analysis comparing the results with previous studies is required. The article should more explicitly highlight both similarities and differences. Such comparisons are crucial for situating the study within the existing body of knowledge and emphasizing its unique contributions or the need for a different approach. The current discussion appears too superficial and does not adequately engage with broader scholarly debates.

Furthermore, the contributions of this research to the field of sustainability, particularly in the transportation and emissions sectors, should be explicitly stated and robustly supported. The article needs to detail how the findings offer new insights or solutions to existing challenges. Currently, while the contributions are mentioned, they are not effectively linked to practical outcomes or future research directions, which lessens their perceived impact.

Conclusion:

Please refer to the comments provided on the discussion section for related feedback. Additionally, it is recommended that the article includes detailed suggestions for future research directions. This should cover potential improvements and unexplored areas that could benefit from further investigation. Outlining these suggestions explicitly would not only enhance the value of the current research but also guide subsequent studies in this field.

Comments on the Quality of English Language

No further comments

Author Response

See the attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript is of interest and well-structured, however the authors are recommended to consider the following issues:

• Discuss/clarify the significance of considering the engine displacement of the vehicle fleet for classification.

• Compare the findings with other classification proposals.

• Propose recommendations for future work.

Author Response

See attached report.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for the opportunity to get acquainted with this interesting manuscript. Indeed, monitoring urban air pollution is an urgent task of our time. The authors consider road transport as the main source of urban air pollution, which is generally quite justified for cities where there are no other powerful sources of pollution, such as mining and processing plants. In general, the article is structured quite logically. But there are a number of flaws in the article. It is not entirely clear which units of measurement are referred to in lines 273-274. Perhaps it is better to display the units of measurement not verbally, but as a fraction. It is desirable to expand the Discussion section by comparing it with air monitoring in other countries that are comparable in terms of climate, degree of development of road transport and other parameters. The article can be published after a little revision

Author Response

See attached report.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The manuscript provides a clean, open-access vehicle stock database, and illustrates the fundamental equation and alternatives for vehicle exhaust emissions analysis. Based on the following comments, the reviewer suggests it requires a major revision.

(1) It would be better to clearly show the contribution to the research field in this manuscript.

(2) Regarding "1. Introduction", reviewing previous research advancements should be further enhanced by adding more detailed descriptions.

 

(3) It would be better if the novelty of the research aim and methodology could be clearly presented in the "Abstract" and "1. Introduction".

Author Response

See attached report.

Author Response File: Author Response.pdf

Round 2

Reviewer 4 Report

Comments and Suggestions for Authors

The reviewer suggests that the manuscript can be accepted.