Examining the Effects of Socioeconomic Development on Fine Particulate Matter (PM2.5) in China’s Cities Based on Spatial Autocorrelation Analysis and MGWR Model

Round 1

Reviewer 1 Report

By using the PM2.5 and socioeconomic data from 2005 12 to 2020 for 359 cities in China, the authors used the spatial autocorrelation and multiscale geographically weighted regression model to analyse the spatio-temporal heterogeneity of PM2.5, and explored the impact of different scales of economic factors. The selection of samples, the use of analytical tools and the analysis results are all appropriate. The conclusion is also interesting. However, there are several problems to be improved:

1. There are few references, especially why the socio-economic indicators sucha as the total population, population density, GDP, the number of industrial enterprise units above the scale, the general public budget revenue of local finance, are selected in this paper? The authors need to give an explanation and support it with literatures.

2. Formula (6) should be related to formula (5), but the formula (6)  is not accurate. Please refer to other literatures for verification.

3. There is redundancy in the text, please check carefully. For example, in rows 108-112, there are two "total population and population density" indicators. The two descriptions of the “average primary and secondary concentration limits” in lines 261-264 are also confusing.

4. As a policy research paper, it is suggested to add some necessary decision support policies at the end of the paper to improve the enlightenment of it.

5. English expression needs improving.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

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Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript investigates the relationship between the PM2.5 concentrations and several socioeconomic parameters and its variations in 2005, 2010, 2015, and 2020 in China. It is an interesting study; however, the writing style is interminable. The authors need to focus on the major results and present concisely. There is a lack of comparison of the results between this study and others. Therefore, a major revision is recommended.

1. All subscript and superscript need to be revised throughout the manuscript.

2. Lines 15-22 are too complex and hard to understand.

3. It is awkward to say that “PM2.5 has been the primary pollutant” in line 36.

4. Reference 3 must be incorrect.

5. “Analysis” in line 98 should be revised.

6. In section 2.2.2, what were the data used for Y and alpha?

7. Where is Bwj(ui,vi) (line 187) in Equation (6)?

8. The mini-map of the nine-dashed line needs to be removed because the authors had no data for this area. Furthermore, it is more related to political issue other than environmental science.

9. Space should be put in legend for all ArcGIS figures, specifically legend in Figure 1i and 1j needs to be revised.

10. Capital letter in line 286.

11. Why is it “worldwide” in line 290?

12. Why is the coefficient in 2020 for GDPP positive, which is totally different from others?

13. The discussion in lines 420-429 seems to be not convincing. GDP per capital is much higher in the eastern part than in the western part. However, the PM2.5 concentration is in fact much higher in the eastern part than in the western part (Figure 2).

14. Lines 455-456 need references.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors have carefully revised according to the comments, and ensured the correctness in the aspects of literature quotation, argument presentation and formula writing. I think this article can be accepted for publication.

Author Response

We appreciate your approval and the advice you provided; it was really beneficial to us. We'll keep working to make our manuscript better. And we'll keep working on it in the future.

Reviewer 3 Report

This research manuscript needs to be related to environmental science only. However, usage of the nine-dash line certainly pulls the manuscript toward political topic. Therefore, it is impossible to further consider the manuscript.

Author Response

Thank you for your suggestion. We have given serious consideration to this issue. However, we are sorry to say that we still wish to retain the nine-dash line.

Firstly, we searched for other pertinent papers in IJERPH and discovered that the nine-dashed line on the map of China was still present. The doi numbers for these publications are as follows: 10.3390/ijerph110100173, 10.3390/ijerph20032316, 10.3390/ijerph20010695, and 10.3390/ijerph192215332 and 10.3390/ijerph192215060.

On the other hand, we carefully read the editing guidelines for the maps and the author instructions on the MDPI website. None of the documents make reference to the requirement to eliminate the nine-dash line in order to prevent the book from deviating into political territory. As a result, we hope you will concur that the nine-dashed line on the map should be kept.