Scientific Knowledge Mapping and Thematic Evolution for Tire Wear Particles
Round 1
Reviewer 1 Report
Object: review of the manuscript "Scientific knowledge mapping and thematic evolution for tire wear particles", which has been submitted to the “sustainability” journal
Overall comment
This paper explores the current literature devoted to tire wear particles (TWP) in the vehicular emissions and the environment. The article draws a picture of the current knowledge on the subject and the stakes to come, which is globally of good quality. However, it has several redundant parts. It is also too focused on publications from a small number of countries (particularly China) and has some problems with the processing of the acquired data. These problems include but are not limited to: i) the lack of consideration of the grey literature, ii) the absence of analysis of the robustness of the data (only one major database considered), and iii) the use of assumptions that are not always verified at the outset of the data treatments performed.
Overall, I recommend that this manuscript to undergo major revisions
SPECIFIC REMARKS
TITLE
The title is fine.
ABSTRACT AND KEYWORDS
The summary is well written and easy to read. However, it is difficult to see what the article proposes that is new or that the community does not already know. From this perspective, it seems that the article is aimed more at a reader who is not familiar with the TWP issue.
Also, mention that the emergence of the TWP issue is also due to the gradual decrease in exhaust emissions.
Keywords are also fine.
1. Introduction
L37: Authors should define what "plastic" means here? Is there a chemical composition or physical properties of reference?
L41: Give the source of the “60% to 70%” data.
L45: Replace "considered" with "currently considered".
L54: It would have been interesting to first evoke the nature and the behavior of primary pollutant of the MP.
L68-70: It would have been interesting to look at the stage of development of TWP research: is it still in full expansion or close to maturity? For this, a comparison with the research on unregulated exhaust emissions or electric vehicles would have been a plus.
2. DATA AND METHODS
L79: Would the results have been significantly different if another scientific research database (e.g. SCOPUS or Google Scolar) had been used? How robust are the results obtained?
L81: Is it possible to identify the bibliographic elements that initiated and brought out this research?
Figure 1: Do you mean "5. Key word analysis"? Also, did you distinguish between studies devoted to TWP and TRWP? If not, why?
L106-110: Why do you favor these countries as starting points and not other regions of the world like North America, Continental Europe, Japan, Australia, etc.? In addition, the countries considered here are hardly comparable: e.g. Macau vs. CPR or England. How does this initial choice affect the knowledge mapping?
3. RESULTS AND discussion
L129-130: Redundant sentence to be removed.
Figure 2: What would this evolution look like if another scientific database had been used?
L174: “USA” instead of “US”.
L150-152: What about the EU (especially Germany, which also seems to play a significant role)?
L174-177: I feel that the authors are overstating the case for China's role in this research. It would also be useful if the authors could mention why these countries/regions are the most active/historically involved in this research (e.g. use of studded tires, more funds available...) and what challenges concern the developing world.
Figure 4: Is it possible to mark collaborations between different numbers of countries with different colors?
Table 1: Replaced "Numbe" by "Number". Also add the year of first publication of a TWP-related article by each journal. In order to judge the accessibility of the literature, it is also important to indicate the share of open access articles related to TWP for each of these journals.
In addition, use only the significant amount of digits in Table 1 figures.
Figure 5: It would also have been interesting to know the contribution/weight of grey literature (e.g. found on platforms such as Google Scolar or Researchgate but not published in these few major journals).
Figure 6: Could you also show in this same figure the ratio between the annual increases associated with each domain and the total publications by domain for year n-1. This would make it possible to assess which aspects of the TWP are the most expanding.
Table 2: Define what does “Total Link Strength” mean and how it was derived.
L314: What is the threshold used to asses keyword termination? How do you ensure the keyword termination?
L315: How is the keyword strength determined?
5. CONCLUSION AND OUTLOOK
The first paragraph of the conclusion is merely a shorter version of the "Results and Discussion" Section. Since it provides no new information, it can be removed from the manuscript.
L355-363: All these elements are also given in the introduction and, therefore, this part can be deleted.
Author Response
Reviewer: 1
OVERALL COMMENT: This paper explores the current literature devoted to tire wear particles (TWP) in the vehicular emissions and the environment. The article draws a picture of the current knowledge on the subject and the stakes to come, which is globally of good quality. However, it has several redundant parts. It is also too focused on publications from a small number of countries (particularly China) and has some problems with the processing of the acquired data. These problems include but are not limited to: i) the lack of consideration of the grey literature, ii) the absence of analysis of the robustness of the data (only one major database considered), and iii) the use of assumptions that are not always verified at the outset of the data treatments performed. Overall, I recommend that this manuscript to undergo major revisions
Response: We appreciate your constructive comments. We have adopted all of the comments to improve the quality of the manuscript. We rechecked the entire manuscript, removed the redundant parts and corrected the corresponding language errors. We have increased the discussion and analysis of more literature contents, and adopted your opinions to add some new viewpoints.
Comment 1: The summary is well written and easy to read. However, it is difficult to see what the article proposes that is new or that the community does not already know. From this perspective, it seems that the article is aimed more at a reader who is not familiar with the TWP issue.Also, mention that the emergence of the TWP issue is also due to the gradual decrease in exhaust emissions.
Response: Thank you for your suggestion. This paper is bibliometrics about TWP, which may focus more on data analysis and statistics. We have revised the article according to your suggestions, adding new views on the TWP field in the keyword analysis part (Lines 283-293) and the conclusion.
Comment 2: L37: Authors should define what "plastic" means here? Is there a chemical composition or physical properties of reference?
Response: Thanks for the suggestion. We added the meaning of "plastic" based on the chemical composition (Lines 35-38).
Comment 3: L41: Give the source of the “60% to 70%” data.
Response: Thanks for the suggestion. We have added the data source (Lines 48).
Comment 4: L45: Replace "considered" with "currently considered".
Response: Thanks for the suggestion. We have corrected at line 48.
Comment 5: L54: It would have been interesting to first evoke the nature and the behavior of primary pollutant of the MP.
Response: Thanks for the suggestion. We have evoked the nature and the behavior of primary pollutant of the TMP (Lines 52-54).
Comment 6: L68-70: It would have been interesting to look at the stage of development of TWP research: is it still in full expansion or close to maturity? For this, a comparison with the research on unregulated exhaust emissions or electric vehicles would have been a plus.
Response: Thanks for your valuable comments. According to the results of literature statistical analysis, the research on TWP is still in the stage of comprehensive development (Line 72). We have adopted your advice and included the development research of new energy vehicles in the analysis and summary.
Comment 7: L79: Would the results have been significantly different if another scientific research database (e.g. SCOPUS or Google Scolar) had been used? How robust are the results obtained?
Response: Thanks for the suggestion. Web of science Core Collection database is a comprehensive and authoritative database at present, and many bibliometrics journals also use WOSCC database (e.g. Xiang S, Mao S, Chen F, et al. A bibliometric analysis of graphene in acetaminophen detection: Current status, development, and future directions[J]. Chemosphere, 2022, 306: 135517. or Mao G, Huang N, Chen L, et al. Research on biomass energy and environment from the past to the future: A bibliometric analysis[J]. Science of The Total Environment, 2018, 635: 1081-1090.). We have also tried to use the academic search you recommended, and the search results are not significantly different from the WOSCC database.
Comment 8: L81: Is it possible to identify the bibliographic elements that initiated and brought out this research?
Response: Thanks for your advice. We have added a summary of the literature that first initiated the TWP research in the introduction section (Lines 44-46). The time range of article retrieval was set to 2000-2021. After screening and analysis, a list of all literatures was derived, which contained the bibliographic elements that initiated and led to this study, and then visual analysis was carried out.
Comment 9: Figure 1: Do you mean "5. Key word analysis"? Also, did you distinguish between studies devoted to TWP and TRWP? If not, why?
Response: Sorry for the confusion, Figure 1 is the analysis flow chart, which is the five analysis directions of the literature. TWP are defined as particles generated mechanically by the rolling shear of tread against a surface (Rogge W F, Hildemann L M, Mazurek M A, et al. Sources of fine organic aerosol. 3. Road dust, tire debris, and organometallic brake lining dust: roads as sources and sinks[J]. Environmental Science & Technology, 1993, 27(9): 1892-1904). As a consequence of the process of formation, TWP are composed of tire tread and particulate matter from road dust. In the environment, pure tire wear particles are rarely found. Instead, particles with a mixed composition consisting of tire and other road related wear particles are present. However, in scientific literature the term ‘tire wear particles (TWP)’ is often used to refer to the heteroaggregates of ‘tire and road wear particles (TRWP)’.
Comment 10: L106-110: Why do you favor these countries as starting points and not other regions of the world like North America, Continental Europe, Japan, Australia, etc.? In addition, the countries considered here are hardly comparable: e.g. Macau vs. CPR or England. How does this initial choice affect the knowledge mapping?
Response: I'm very sorry for the misunderstanding. First of all, the international cooperation model is based on national units, and the international cooperation network map also includes North America, continental Europe, Japan, Australia and other parts of the world. Because some countries or regions have fewer research results, we set a threshold of 3 publications. In this way, the contribution and cooperation of various countries can be seen more cleanly in the knowledge graph.
Comment 11: L129-130: Redundant sentence to be removed.
Response: We accept the suggestion and have removed the redundant sentence at line 133.
Comment 12: Figure 2: What would this evolution look like if another scientific database had been used?
Response: Sorry for the confusion, the Web of science Core Collection database already contains the academic achievements of research value in recent years. We also tried using other databases, and the results were not much different from the core database.
Comment 13: L174: “USA” instead of “US”.
Response: Thanks for the suggestion. We have corrected at line 137.
Comment 14: L150-152: What about the EU (especially Germany, which also seems to play a significant role)?
Response: We agree with you and we have revised this sentence and added a detailed description at lines 139-141.
Comment 15: L174-177: I feel that the authors are overstating the case for China's role in this research. It would also be useful if the authors could mention why these countries/regions are the most active/historically involved in this research (e.g. use of studded tires, more funds available...) and what challenges concern the developing world.
Response: Thanks for the suggestion. We have reduced the narrative of the content about China, while taking your advice, increasing the contribution of some regions or countries to the TWP research field, while supplementing the challenges faced by developing countries (Lines 159-170).
Comment 16: Figure 4: Is it possible to mark collaborations between different numbers of countries with different colors?
Response: Thanks for the suggestion. We have revised the colors of the figures at line 171.
Comment 17: Table 1: Replaced "Numbe" by "Number". Also add the year of first publication of a TWP-related article by each journal. In order to judge the accessibility of the literature, it is also important to indicate the share of open access articles related to TWP for each of these journals.
Response: Thanks for the suggestion. We have corrected in Table 1. We accept the suggestion and add the year of first publication of a TWP-related article by each journal (Lines 180-181). The share of TWP-related open access articles in these journals is also indicated.
Comment 18: Figure 5: It would also have been interesting to know the contribution/weight of grey literature (e.g. found on platforms such as Google Scolar or Researchgate but not published in these few major journals).
Response: Thank you for your comments and we have added the contribution/weight of grey literature to carry out the study (Lines 198-202).
Comment 19: Figure 6: Could you also show in this same figure the ratio between the annual increases associated with each domain and the total publications by domain for year n-1. This would make it possible to assess which aspects of the TWP are the most expanding.
Response: Thank you for your suggestion. Since the number of published papers is mainly concentrated in the field of environmental science, and the number of published papers in other fields is small, it is not obvious to represent the growth rate in picture form. For this reason, we have added the trend of growth of related fields in the paper (Lines 210-211).
Comment 20: Table 2: Define what does “Total Link Strength” mean and how it was derived.
Response: Sorry for the confusion, total link strength refers to the total number of co-occurrences of keywords and other keywords (including the number of repeated co-occurrences). Total link strength is obtained by analyzing the aggregated literature data with VOSviewer software.
Comment 21: L314: What is the threshold used to asses keyword termination? How do you ensure the keyword termination?
Response: Sorry for the confusion. Using the VOSviewer software, we set the minimum number of keyword occurrences to 20, and the total strength of co-occurrence with other keywords is computed for the initial selected keywords. The keywords with the highest total link strength will be chosen. Finally, selected keywords are checked and keywords unrelated to the TWP search are removed.
Comment 22: L315: How is the keyword strength determined?
Response: Sorry for the confusion, both VOSviewer and CiteSpace software can first summarize the key word matrix from the literature information, and then generate the co-word matrix based on the key matrix. Visualization technology allows the co-word matrix to be visualized as a network to display the strength of keywords.
Comment 23: The first paragraph of the conclusion is merely a shorter version of the "Results and Discussion" Section. Since it provides no new information, it can be removed from the manuscript.
Response: Thanks for the suggestion. We have cut out the first paragraph.
Comment 24: L355-363: All these elements are also given in the introduction and, therefore, this part can be deleted.
Response: Thank you very much for your advice. We have cut this paragraph and added new ideas (Lines 304-316).
Reviewer 2 Report
All the 499 valid documents are obtained from the WOSCC, and the research process is analyzed using the VOSviewer. Why do you enlarge the documents from the EI database?
In fact, this paper is only a statistical analysis, and the conclusion is not rich enough. It is advised that more documents is should be analyzed to point out the research hotspots, and provide some valuable research interests.
Author Response
Reviewer: 2
General comment: All the 499 valid documents are obtained from the WOSCC, and the research process is analyzed using the VOSviewer. Why do you enlarge the documents from the EI database? In fact, this paper is only a statistical analysis, and the conclusion is not rich enough. It is advised that more documents is should be analyzed to point out the research hotspots, and provide some valuable research interests.
Response: Thanks for the suggestion. Web of science Core Collection database is a comprehensive and authoritative database at present, and many bibliometrics journals also use WOSCC database (e.g. Xiang S, Mao S, Chen F, et al. A bibliometric analysis of graphene in acetaminophen detection: Current status, development, and future directions[J]. Chemosphere, 2022, 306: 135517. or Mao G, Huang N, Chen L, et al. Research on biomass energy and environment from the past to the future: A bibliometric analysis[J]. Science of The Total Environment, 2018, 635: 1081-1090.). We have also tried to use the academic search you recommended, and the search results are not significantly different from the WOSCC database.
Thank you very much for your good advice. Given that current TWP research is still in a state of comprehensive development and that the total number of papers is small, a total of 499 papers with research value were selected. Based on your views, we have amended the full paper, added more literature reviews and research hotspots, and highlighted the current state of research and future research direction in the results and discussion section.
Round 2
Reviewer 1 Report
Object: 2nd review of the manuscript "Scientific knowledge mapping and thematic evolution for tire wear particles", which has been submitted to the “Sustainability” journal
Overall comment
The authors have partially responded to my comments on the funding of TWP research and the need for future research that includes developing countries. They also now offer a less subjective view of the role of countries like China. Unfortunately, many of the responses and improvements made to the article are mostly about form with less change in substance. For instance, the article could be further enriched with the elements provided in the discussion of with authors on: assessing the robustness of the results with additional databases, or on further study of the grey literature (at the same level as the literature proposed by the high-ranking journals). Typing or editing errors persist, as in the text of the tables in Figure 1.
Overall, I recommend that this manuscript to undergo minor revisions
SPECIFIC REMARKS
I am surprised that the authors point out the absence of any research on the presence and fate of TWPs in environmental compartments when to my knowledge there are several (e.g. https://doi.org/10.1016/j.scitotenv.2020.144785). An update of the article figures may be necessary.
Again, several answers to my comments are interesting and deserve to be better highlighted in the revised document: e.g. on the distinction between TWP and TRWP, or on the similarity of results between commercial or high-rank publication databases and those dedicated to grey literature, on how were the keyword strength and other variables determined…
Finally, I think the article should be carefully reviewed by the authors and/or the editor to get rid of minor English and, more importantly, editing errors.
Author Response
please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Nothing. The revised paper can be published.
