Urban Green Space and Mental Health: Mechanisms, Methodological Advances, and Governance Pathways for Sustainable Cities

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This review provides a solid foundation for the research field: it synthesizes empirical studies and bibliometric records, clarifies the pathways through which urban green space (UGS) impacts mental health, and clearly outlines the three stages of methodological evolution. The overall framework enables readers to quickly grasp the landscape of the field, and the dual-dataset design (bibliometric analysis combined with empirical synthesis) makes this review more comprehensive than single-synthesis ones. These are all noteworthy strengths. However, the paper still has several aspects that need improvement:

Potential bias in literature screening

The authors only searched two databases and did not include commonly used databases such as Scopus and CNKI, which may lead to the omission of some important studies. This lack of comprehensiveness compromises the rigor of the review, and a detailed explanation for this database selection is required.

Unclear incremental contribution and insufficient citation of recent high-quality reviews

Several high-quality reviews have been published in this field in the past five years (e.g., How Does Urban Green Space Impact Residents’ Mental Health: A Literature Review of Mediators, Associations Between Urban Green Space Quality and Mental Wellbeing: Systematic Review), yet they seem to be insufficiently cited in this paper. This raises critical questions: Has the paper fully synthesized existing research? What exactly is its incremental contribution? The paper fails to clearly elaborate on and compare its differences from previous reviews, which may give readers the impression of redundant research.

Superficial theoretical integration

The six core pathways are merely listed rather than truly integrated. The authors present these pathways side by side but do not clarify their inherent interconnections—for instance, whether there are mediating or moderating relationships between different pathways, and which pathway dominates in specific scenarios. The lack of in-depth analysis results in a fragmented framework with insufficient theoretical depth.

Unspecified applicable boundaries of the theoretical framework

The paper does not address the adaptability of the proposed socio-ecological framework across different climates, urban forms, and cultural contexts. Without defining these boundaries, the generalizability of the framework is questionable.

Neglected limitations of bibliometric methods

Key methodological details such as the threshold selection for keyword co-occurrence analysis and the standardization of keywords are not clearly explained. Additionally, potential biases of the applied methods are not discussed, which needs to be addressed to verify the reliability of the bibliometric results.

Shallow analysis of dynamic exposure

Dynamic exposure is a current research hotspot in this field, yet the authors only categorize it as one stage of methodological evolution without an in-depth discussion of the advantages, disadvantages, and application challenges of relevant technical methods. This fails to meet the requirement of a review to deconstruct cutting-edge methodological advances.

Avoidance of controversial issues in the field

The paper does not address core controversial topics, such as whether there is a saturation threshold for the effects of UGS, how to explain the negative correlations found in some studies, and whether there are differences in therapeutic effects between artificial and natural green spaces. The avoidance of these controversies makes the research less objective and comprehensive.

Confusion between correlation and causation in some expressions

Occasional statements such as "UGS causes improvements in mental health" appear in the paper. However, most research in this field remains correlational, and causal inference is still in the exploratory stage. Such expressions may mislead readers and should be revised to neutral phrasing.

Need for improvement in figure quality

Some figures suffer from overly high color saturation, which reduces readability. In addition, legend labeling is not standardized in certain parts, making it difficult for readers to quickly understand the core relationships presented.

Format and minor details omissions

Some low-frequency abbreviations and interdisciplinary terms are not accompanied by their full names or English counterparts when first mentioned in the paper.

 

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors,

Firstly, I would like to thank you for your work in this field.
You did a good job!
After extensive reading, I only have a few comments for the current version, which are not many but essential.
For revision details, please see the following:

1. the topic of the paper has strong practical significance, but the main line of research is still scattered. At the same time, the article discusses the three dimensions of mechanism, method progress and governance path, but lacks a clear theoretical framework to organically integrate the three, resulting in the overall structure biased towards the plate review, rather than the systematic demonstration around the core research issues;

2. the mechanism analysis part is still partial to the general statement. Although the theory of psychological recovery, stress relief path and social interaction mechanism are mentioned, there is a lack of in-depth integration of the hierarchical relationship, interaction and differences between different mechanisms in different urban situations, and the degree of theoretical deepening needs to be strengthened;

3. the review of methodological progress mainly focuses on tools and technologies, such as remote sensing data, physiological indicators or big data analysis. However, there is insufficient discussion on the limitations of these methods in causal identification, sample bias and ethical issues, and a critical method evaluation has not yet been formed;

4. the connection between empirical research and governance path is still not close enough. The article puts forward several policy suggestions, but the logical correspondence between these suggestions and the mechanism analysis above is not clear enough. Some governance paths are more like general initiatives than the strategic framework based on systematic evidence derivation;

5. the analysis of differences between different social groups is still relatively limited. Although the issues of equity and sustainability are mentioned, there is no systematic discussion on the structural differences in green space accessibility and mental health benefits among vulnerable groups, people of different ages or different socio-economic backgrounds;

6. the conclusion part summarizes the reflection on the limitations of the research and the future research direction, especially in terms of data heterogeneity, cross-cultural comparability and lack of long-term longitudinal research. It is suggested to further strengthen the prudence of the method and the explanation of the theoretical boundary.

 

If my comments are properly considered and followed, I have no further comments on this manuscript.
Again, I have a high comment on your current contribution. 
All my upon-revision recommendations are intended to help this manuscript be more readable for readers.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This review synthesises 113 empirical studies and 929 bibliometric records to examine how urban green space influences mental health, integrating six validated pathways into a unified socio-ecological framework. It highlights a methodological shift toward dynamic, multimodal exposure assessment and more rigorous causal and spatial modelling, alongside growing interdisciplinarity in the field. The authors identify persistent gaps in exposure alignment and generalisability, and propose a governance-oriented framework to translate evidence into equitable, data-driven urban planning for healthier cities.

Overall, the paper is well structured and clearly written. It makes a timely and meaningful contribution to the field and can be published subject to minor revisions.

(1) Section 3 (Methods) clearly outlines the processes and techniques adopted in the review, which is commendable. However, the manuscript would be strengthened by further explaining why these specific methods were selected and how they complement one another. A brief discussion of alternative approaches and justification for the chosen methods would enhance methodological transparency and rigour.

(2) Several figures appear overly large, heavily coloured, unnecessarily complex, or difficult to read. The authors are encouraged to refine the visual materials to improve clarity and overall presentation quality.

(3) Some sub-sections contain very limited content and could be consolidated to improve structural coherence. In addition, the formatting and organisation of sub-sections are not entirely consistent throughout the manuscript and should be standardised.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I have reviewed the author's revised manuscript and can clearly sense that they have made systematic revisions based on the first-round review comments. The progress is indeed remarkable. The revised manuscript clearly explains the differences from previous similar reviews and the newly added value, and also supplements the specific details of the bibliometric methods, mentions the limitations of this method, corrects the previous confusion in causal statements, and clarifies the situations under which the theoretical framework is applicable. Overall, the academic rigor and transparency of the manuscript have improved significantly, and the core academic value, research design, and the reliability of the conclusion are much better than before.

 

However, there are still a few minor details that I think can be further improved. Specifically:

 

1. It is recommended to strengthen the empirical support of the six major action paths. It doesn't need to be too complex. Just summarize 1-2 typical studies in terms of the mediating or moderating effects of the paths. This will enable a closer combination of theory and practical research and avoid remaining only at a purely qualitative description level.

 

2. For the dynamic exposure analysis part, it can be supplemented with the applicable scenarios of different assessment techniques. Briefly explain what each method is suitable for in certain situations. This way, readers can quickly distinguish the advantages and applicable scope of each method without spending too much space on systematically reviewing causal inference methods.

 

3. In the discussion section, it can be appropriately mentioned the negative correlation phenomena found in a few studies, briefly analyze what might be the reasons for this and how to avoid such situations. This will make the argument more comprehensive and balanced.

 

4. In the section on research limitations or future research directions, it can briefly mention the controversial points in this field that have not yet reached consensus, such as the saturation threshold of UGS exposure, the effect differences between artificial green spaces and natural green spaces, etc. Explain that these controversies still require more cross-regional and long-term research to verify. This will demonstrate an objective understanding of the entire research field and make the discussion more balanced.

 

5. In the conclusion regarding the universality of the framework, it can be slightly narrowed down. Based on the current regional coverage of existing research, clearly define the applicable boundaries of this framework. Don't make it too generalized.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

no further comments.

Author Response

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Author Response File: Author Response.pdf