Effects of Different Site Conditions on the Concentration of Negative Air Ions in Mountain Forest Based on an Orthogonal Experimental Study

Round 1

Reviewer 1 Report

Thank you, authors and editor, for the opportunity to review this paper. The manuscript entitled "Effects of Different Site Conditions on the Concentration of Negative Air Ions in Mountain Forest Based on a Orthogonal Experimental study" has identified NAI variation in the forest due to environmental factors. The results and findings of the paper are exciting and can be valuable for the broader community. However, a few things need to be addressed before it becomes publishable in the Sustainability journal. 

Comment 1: The paper used topographic factors. However, the paper missed the most important factors such as "Aspects" or "Exposure" in the analysis. The forests situated in the southern and northern aspects of the topography have different levels of moisture content and intensity of sunlight or rays, which directly affect NAI. I suggest authors include this variable. If data is not available, please try to compensate it through the study limitation or future research direction.

Comment 2: Results on page 8, line: 242, and discussion on Page 11, line 360 are completely contradicting. For instance: "Wind velocity had no significant effect" and "wind velocity strongly affects the accumulation of NAI."

Suggestion: I believe this manuscript will greatly impact the public audience, policymakers, and researchers. So I suggest authors write a couple of sentences about the policy recommendations and/or any future research direction in the CONCLUSION section.

More specific comments:

1. Page 7, line- 208; Maybe TYPO "NAs."
2. Page 9, line-260; grammatical inconsistent with all other findings

Author Response

Dear editor and reviewers:

Thanks for your letter and for reviewers’ comments concerning our manuscript entitled “Effects of Different Site Conditions on the Concentration of Negative Air Ions in Mountain Forest Based on an Orthogonal Experimental Stud” (Manuscript ID: sustainability-1390725). Those comments are all valuable and helpful for revising and improving our paper. We have studied all comments carefully and have made conscientious correction. Revised portion are marked in red in the paper. The main corrections in the paper and the responds to the reviewers’ comments are as flowing. We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. We appreciate for reviewers’ warm work sincerely, and hope that the correction will meet with approval.

Once again, thank you very much for your comments and suggestions.

All the authors

October 23, 2021

Reviewer 1：

Comments to the Author:

Comment 1: The paper used topographic factors. However, the paper missed the most important factors such as "Aspects" or "Exposure" in the analysis. The forests situated in the southern and northern aspects of the topography have different levels of moisture content and intensity of sunlight or rays, which directly affect NAI. I suggest authors include this variable. If data is not available, please try to compensate it through the study limitation or future research direction.

Response: We thank the reviewer for the very interesting comment. In fact the research site of this study (Taibai Mountain National Forest Park) is located on the Northern Slope of The Qinling Mountains, so all the monitoring sites in our study belong to the forests in the north of the terrain. Montain forests located on the south and north sides of the terrain can indirectly affect NAI by affecting water content, sunlight, or light intensity. Regarding the suggestion about the topographic factors, we further explained in section 2.2 (Orthogonal Experiment Design) of the revised manuscript. The influence of forest on NAI in the north and south of terrain has been added in the study limitation or future research direction.

Comment 2: Results on page 8, line: 242, and discussion on Page 11, line 360 are completely contradicting. For instance: "Wind velocity had no significant effect" and "wind velocity strongly affects the accumulation of NAI."

Response: Thanks for the reviewer's correction. We have corrected this mistake in the revised manuscript.

Suggestion: I believe this manuscript will greatly impact the public audience, policymakers, and researchers. So I suggest authors write a couple of sentences about the policy recommendations and/or any future research direction in the CONCLUSION section.

Response: We are grateful for the suggestion. To be more clear and in accordance with the reviewer concerns, we have added a brief description as follows: “We suggest that researchers or policy makers take into account altitude, canopy density and topographic factors that affect NAI concentration when studying or establishing sites for health promotion activities in forest parks in the future.”.

More specific comments:

1. Page 7, line- 208; Maybe TYPO "NAs"

Response: Modified throughout the text according to the comment (Line 213, page 7). "NAs" has been modified to "NAI".

2. Page 9, line-260; grammatical inconsistent with all other findings

Response: Modified throughout the text according to the comment (Line 260, page 9). 

Author Response File: Author Response.doc

Reviewer 2 Report

Comments for authors:

• There are many English style errors throughout the all manuscript, e.g., line 54-56; 92-94, etc. It must be revised thoroughly to make it clear.
• The concentration of NAI varied highly at different sites and times. You collected data from only one year data (2021), can it be repeated in the next year or not? I think the experiment replicates are necessary.
• Terrain, altitude and canopy density that you selected for investigation are correlated with each other. The PCA analysis may be useful to characterize the key factor, which is easy-to-use to help design suitable parks for people health.
• The NAI concentrations of T1A3C1 and T2A3C1 are not significantly different. The reasons for this result should be discussed in details.
• The experimental design was an L9 orthogonal array, in each array how many replicates were conducted? At least three similar sites are needed for measure NAI concentration. And the average value is more suitable for subsequent statistical analyses.

 

Author Response

Dear editor and reviewers:

Thanks for your letter and for reviewers’ comments concerning our manuscript entitled “Effects of Different Site Conditions on the Concentration of Negative Air Ions in Mountain Forest Based on an Orthogonal Experimental Stud” (Manuscript ID: sustainability-1390725). Those comments are all valuable and helpful for revising and improving our paper. We have studied all comments carefully and have made conscientious correction. Revised portion are marked in red in the paper. The main corrections in the paper and the responds to the reviewers’ comments are as flowing. We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. We appreciate for reviewers’ warm work sincerely, and hope that the correction will meet with approval.

Once again, thank you very much for your comments and suggestions.

All the authors

October 23, 2021

Reviewer 2：

Comments to the Author:

Comment 1: There are many English style errors throughout the all manuscript, e.g., line 54-56; 92-94, etc. It must be revised thoroughly to make it clear.

Response: Modified throughout the text according to the comment (line 54-56; 92-94, etc.). 

Comment 2: The concentration of NAI varied highly at different sites and times. You collected data from only one year data (2021), can it be repeated in the next year or not? I think the experiment replicates are necessary.

Response: In this study, the peak number of visitors in mountain forest parks was selected to conduct a short-term study on the impact of NAI concentration. We have made a supplementary explanation in the limitation part of the article. Monitoring time also has a great influence on NAI concentration, which will be reflected in our next study.

Comment 3: Terrain, altitude and canopy density that you selected for investigation are correlated with each other. The PCA analysis may be useful to characterize the key factor, which is easy-to-use to help design suitable parks for people health.

Response: We thank the reviewer for raising this question. We tried to use principal component analysis to analyze topography, elevation and canopy density. However, as these three variables in our experiment are not quantifiable random variables, they do not meet the conditions of principal component analysis. We refer to the relevant literature, for the orthogonal experiment of three indicators and three levels, only the orthogonal analysis can get the importance of factor influence. We have carried out orthogonal analysis of the results in this paper. We will consider re-quantitative analysis of these indicators in our future research. Here are some similar literatures we found. Thank you again for your comments.

• Chen M ,  Zeng X ,  Liu Y , et al. An orthogonal design of light factors to optimize growth, photosynthetic capability and metabolite accumulation of Anoectochilus roxburghii (Wall.) Lindl[J]. Scientia Horticulturae, 2021, 288:110272.
• Xu H ,  Li J ,  Wu J , et al. Evaluation of Wood Coverage on Building Facades Towards Sustainability[J]. Sustainability, 2019, 11.

Comment 4: The NAI concentrations of T1A3C1 and T2A3C1 are not significantly different. The reasons for this result should be discussed in details.

Response: Thanks for the comment. We have modified it in the new manuscript.

Comment 5: The experimental design was an L9 orthogonal array, in each array how many replicates were conducted? At least three similar sites are needed for measure NAI concentration. And the average value is more suitable for subsequent statistical analyses.

Response: Three samples were selected for each array combination. The statistical data is the average of the three samples. We made a supplement in section 2.2 (Orthogonal Experiment Design) of the revised manuscript.

Author Response File: Author Response.doc

Reviewer 3 Report

Comments and Suggestions for Authors

Title：Effects of Different Site Conditions on the Concentration of Negative Air Ions in Mountain Forest Based on an Orthogonal Experimental Study

Interesting research, which could be a theoretical foundation for forest trips, NAI in there, waiting for someone.

1. 06h31,18h30, 16h00, et al, means what? In Lines 22,23,26.
2. in abstract, needs some data support your results or conclusion.
3. too many keywords, are you agree?
4. line 40, the references [3,4] should seated at the end of the sentence.
5. line 39, before [2], the sentence is not complete, please check it.
6. abundant reviews showed in introduction, but needs more improved for a better description, such as from line 44 to 46.
7. why chose the tourist season in 2021?
8. the data collection periods (1-5 May, 2021), long enough?
9. the sentences of the results part needs optimized.

For example, Figure 1 shows….line 162, by analyzing ……line 170, Table 2 provides……line 182, et al, not very suitable.

10. figure 1 based on the mean value of NAI in 5 days or 1 day??

 “The mean values of each group were compared using Duncan’s

194 multiple range tests” has showed in statistical analysis, deleted it, ok?

11. figure 3, the X, Y axis should change each other, NAI is the dependent variable.
12. the description of paragraph from line0197-217, not very good, the compare style is unscientific (as: K1>K2>K3 with C1>C2>C3), (K3>K2>K1 with A3<A2<A1).
13. line 376 to 381, why here? Should put in 5. Conclusions, do you think so?
14. “The results showed the optimal site conditions for producing the highest concentration of NAI in the selected forest, as determined by orthogonal design and by investigating the correlation of meteorological factors on NAI concentrations” I was confused. Site conditions for highest concentration of NAI, determined by orthogonal design and by investigating of ……, which was the main reason for the highest NAI. Line 384-386
15. the part of introduction should be improved words by words, make every paragraph connected closely and logically.
16. the whole research paper could be better than current one, please improve it under some helps.

Author Response

Dear editor and reviewers:

Thanks for your letter and for reviewers’ comments concerning our manuscript entitled “Effects of Different Site Conditions on the Concentration of Negative Air Ions in Mountain Forest Based on an Orthogonal Experimental Stud” (Manuscript ID: sustainability-1390725). Those comments are all valuable and helpful for revising and improving our paper. We have studied all comments carefully and have made conscientious correction. Revised portion are marked in red in the paper. The main corrections in the paper and the responds to the reviewers’ comments are as flowing. We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. We appreciate for reviewers’ warm work sincerely, and hope that the correction will meet with approval.

Once again, thank you very much for your comments and suggestions.

All the authors

October 23, 2021

Reviewer 3：

Comments to the Author :

1. 06h31,18h30, 16h00, et al, means what? In Lines 22,23,26.

Response: 06h31,18h30, 16h00 and so on represent the time, “6:31am”, “18:30pm”and “16:30pm”, which have been changed in the revised manuscript.

2. in abstract, needs some data support your results or conclusion.

Response: Some data have been added to the ABSTRACT as suggested of reviewer.

3. too many keywords, are you agree?

Response: After much deliberation, we removed the key word "Orthogonal Experimental."

4. line 40, the references [3,4] should seated at the end of the sentence.

Response: Thanks for the comment. We have modified it in the new manuscript.

5. line 39, before [2], the sentence is not complete, please check it.

Response: Thanks for the comment. We have modified it in the new manuscript.

6. abundant reviews showed in introduction, but needs more improved for a better description, such as from line 44 to 46.

Response: Thanks for the comment. We have modified it in the new manuscript.

7. why chose the tourist season in 2021?

Response: The reason for choosing the peak tourist season is that people have more demand and willingness to contact the forest during the peak tourist season. The aim of our study was to find the mountain forest site with the highest NAI concentration and the factors influencing NAI concentration. These are based on the desire and need of visitors to access mountain forests for health promotion activities. Therefore, the tourist season is typical and representative.

8. the data collection periods (1-5 May, 2021), long enough?

Response: In this study, the peak number of visitors in mountain forest parks was selected to conduct a short-term study on the impact of NAI concentration. We have made a supplementary explanation in the limitation part of the article. Monitoring time also has a great influence on NAI concentration, which will be reflected in our next study.

9.the sentences of the results part needs optimized.

For example, Figure 1 shows….line 162, by analyzing ……line 170, Table 2 provides……line 182, et al, not very suitable.

Response: Thanks for the comment. We have modified it in the new manuscript.

10.figure 1 based on the mean value of NAI in 5 days or 1 day??

“The mean values of each group were compared using Duncan’s

194 multiple range tests” has showed in statistical analysis, deleted it, ok?

Response: Figure 1 based on the mean value of NAI in 5 days, and "The mean values of each group were compared using Duncan's Multiple Range Tests "have been removed from the new manuscript.

11. figure 3, the X, Y axis should change each other, NAI is the dependent variable.

Response: Thanks for the comment. We have modified it in the new manuscript.

12. the description of paragraph from line0197-217, not very good, the compare style is unscientific (as: K1>K2>K3 with C1>C2>C3), (K3>K2>K1 with A3<A2<A1).

Response: Thanks for the comment. We have modified it in the new manuscript.

13. line 376 to 381, why here? Should put in 5. Conclusions, do you think so?

Response: Thanks for the comment. We have modified it in the new manuscript.

14. “The results showed the optimal site conditions for producing the highest concentration of NAI in the selected forest, as determined by orthogonal design and by investigating the correlation of meteorological factors on NAI concentrations” I was confused. Site conditions for highest concentration of NAI, determined by orthogonal design and by investigating of ……, which was the main reason for the highest NAI. Line 384-386

Response: Yes, Site conditions for highest concentration of NAI, determined by orthogonal design and by investigating of ……, which was the main reason for the highest NAI. We have modified it in the new manuscript.

15. the part of introduction should be improved words by words, make every paragraph connected closely and logically.

Response: Thanks for the comment. We have modified it in the new manuscript.

16. the whole research paper could be better than current one, please improve it under some helps.

Response: Thanks for the comment. We have modified it in the new manuscript.

Author Response File: Author Response.doc

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.