Recent Research Progress on Nitropolycyclic Aromatic Hydrocarbons in Outdoor and Indoor Environments
Round 1
Reviewer 1 Report
The manuscript is a review on recent research progress on NAHs in the environment.
In summary it is not clear what the aim of this paper is. It states to contain new information to a previous review paper, but it is not clear what the new information really is. Surely, the tables list lot of information, but it is unclear to me what the additional value of these lists is. The paper needs to be structured better and especially chapter 2 needs more scientific depth. The wording should be improved. The paper in the present form should not be published because is not scientifically sound.
Throughout the manuscript important references missing to underline the facts, i.e. line 31, 34, 79, 294, 312, 314, 316, 352, 357. In reference no. 6 I noticed that the title of the reference is missing in the bibliography at the end.
The introduction to the topic and the conclusion and the abstract do not fit together, there are different. In my opinion the first paragraph of the conclusion would be better included within the introduction.
The fact that NPAHs are mutagenic is not referenced within the document. Some paragraphs need to be structured better and sometimes the scientific writing needs to be improved, i.e. line 50-56.
The statement of line 48-49 is contrary to the lines before.
Chapter 2 needs to be enriched with more detailed information, some of the information is not clear. A chart would be helpful, some chemical structures as well. What is meant with segments in line 67? In line 65 it would be good to know which metal ions are meant. The statements in this para should be discussed here – whould be expected from a review.
What was the result of studies 16-18 referenced in lien 66? The wording in line 68 needs to be improved.
Line 69-72: logic of the sentence is unclear
Line 81: what are QPAHs (should be explained)
Line 83-84: explanation mission what post-emission stability indicators are.
Chapter 3:
- Wording in line 90 should be improved. Cleanup and concentration are not the specific wording for what is meant.
- The whole chapter describes basic chemistry which could be found in a textbook. What is the new scientific information for this review?
Chapter 4:
Line 188: source analysis method (not clear what this is, wording should be improved)
Line 189, 218: the wording needs to be improved.
Chapter 5:
- Overall question: what is the new information?
- Line 301: what is extremely small?
- Para 302-309: some numbers would be good to get a better understanding regarding the concentrations.
- Line 358-362: iteration
- Line 363-369: what was the result from the studies 108,110?
- Line 377-381: a bit too short for a single chapter.
Author Response
To Reviewer #1
Thank you very much for your careful reviewing.
In summary it is not clear what the aim of this paper is. It states to contain new information to a previous review paper, but it is not clear what the new information really is. Surely, the tables list lot of information, but it is unclear to me what the additional value of these lists is. The paper needs to be structured better and especially chapter 2 needs more scientific depth. The wording should be improved. The paper in the present form should not be published because is not scientifically sound.
← According to your kind and useful comment, I have revised the manuscript as follows.
- Throughout the manuscript important references missing to underline the facts, i.e. line 31, 34, 79, 294, 312, 314, 316, 352, 357. In reference no. 6 I noticed that the title of the reference is missing in the bibliography at the end.
← According to your suggestion, I have cited references to the all. The title of the reference 6 has been added (lines 445-446).
- The introduction to the topic and the conclusion and the abstract do not fit together, there are different. In my opinion the first paragraph of the conclusion would be better included within the introduction.
← Thank you very much for your comment. I have moved the first sentence from 6. Conclusion to 1. Introduction with adding several sentences (lines 44-49, 56-57, 61-63). Also Abstract, 1. Introduction and 6. Conclusion have been revised to fit to each other by adding several sentences as described below.
- The fact that NPAHs are mutagenic is not referenced within the document. Some paragraphs need to be structured better and sometimes the scientific writing needs to be improved, i.e. line 50-56.
← Thank you very much for your useful comment. I have revised several parts of 1. Introduction by adding important information as described in 2).
- The statement of line 48-49 is contrary to the lines before.
← The sentence has been deleted to avoid confusion.
- Chapter 2 needs to be enriched with more detailed information, some of the information is not clear. A chart would be helpful, some chemical structures as well. What is meant with segments in line 67? In line 65 it would be good to know which metal ions are meant. The statements in this para should be discussed here – whould be expected from a review.
← According to your useful comment, I have added several sentences to increase scientific depth (lines73-75, 76-79). Nitration of several PAHs by Asian dust has been added (lines 81-82) with reference [19].
- What was the result of studies 16-18 referenced in lien 66? The wording in line 68 needs to be improved.
← Yes. According to your comment, the sentence has been revised to make clear (lines 84-86).
- Line 69-72: logic of the sentence is unclear
← The sentence has been revised to make clear (lines 85-86).
- Line 81: what are QPAHs (should be explained)
← “QPAHs” is defined in 1. Introduction (line 50).
- Line 83-84: explanation mission what post-emission stability indicators are.
← According to your comment, several words have been added (line 99).
- Chapter 3:　Wording in line 90 should be improved. Cleanup and concentration are not the specific wording for what is meant.
← According to your comment,　the sentence has been revised (line 106).
- The whole chapter describes basic chemistry which could be found in a textbook. What is the new scientific information for this review?
← According to your important comment,　important points have been emphasized in chapters 3.1. (lines 108-109) and 3.2. (lines 173-174).
- Chapter 4: Line 188: source analysis method (not clear what this is, wording should be improved); Line 189, 218: the wording needs to be improved.
← According to your suggestion,　titles of 4., 4.1. and 4.2. have been modified by adding several words.
- Chapter 5: Overall question: what is the new information?
← Considering to your important comment, I have modified this chapter by adding several sentences to emphasize the new information (lines 325-329, 364-365).
- Line 301: what is extremely small?
← Several words have been changed to “very few submissions from Africa” to male clear (lines 319-320).
(15) Para 302-309: some numbers would be good to get a better understanding regarding the concentrations.
← According to your suggestion, sentences have been added to explain the difference between Chinese and Japanese cities with concentrations (line 325-329).
(16) Line 358-362: iteration
← The sentence has been delated to avoid confusion.
(17) Line 363-369: what was the result from the studies 108,110?
← The paragraph has been revised to show the result clear (lines 391-392).
(18) Line 377-381: a bit too short for a single chapter.
← According to your comment, the paragraph has been moved into chapter 5.1.
Reviewer 2 Report
The article reviews the current literature about PAHs and NPAHs by focusing on their formation process, sampling, chemical analysis, and sources. Given the importance of PAHs in terms of adverse effects on human health, it’s crucial to investigate their characteristics and sources. This becomes even more important for NPAHs as they’re more carcinogenic and mutagenic. The paper is well written and comprehensively discusses the chemical properties of PAHs as well as their source apportionment techniques. In my view, it merits publication after including some further details following the comments below:
1) The Introduction is focused on the health effects of PAHs and NPAHs (which is the most important topic when it comes to PAHs). However, it’s worth adding the importance of PAHs in aerosol light absorption. Studies have shown that high molecular weight PAHs are important contributors to brown carbon light absorption and NPAHs are even more efficient UV absorbers.
- doi.org/10.1080/02786826.2020.1726867
- doi.org/10.1021/acs.est.8b02386
- doi.org/10.1016/j.scitotenv.2019.135902
2) Line 191: For better clarification, the PCA and PMF methods are known as factor analysis tools, which don’t necessarily belong to chemical mass balance category. The pure CMB method is conducted by MM-CMB. On the other hand, although PMF solves the CMB equation, the target variable is not necessarily re-constructed based on the mass of individual components (used as the input to the model), rather the relative association between normalized levels of species matters.
3) Lines 337-342: There have been studies conducted in Europe observing high levels of PAHs due to biomass burning in winter (that was higher than typical PAHs levels in east Asia, middle East, and USA).
- doi.org/10.1016/j.atmosenv.2006.12.053
- doi.org/10.1016/j.scitotenv.2020.143582
- doi.org/10.1016/j.scitotenv.2011.11.026
4) Lines 352-357: Similar to comment #3, biomass burning is also an important source of PAHs and should be added here.
Author Response
To Reviewer #2
Thank you very much for your kind comment.
The article reviews the current literature about PAHs and NPAHs by focusing on their formation process, sampling, chemical analysis, and sources. Given the importance of PAHs in terms of adverse effects on human health, it’s crucial to investigate their characteristics and sources. This becomes even more important for NPAHs as they’re more carcinogenic and mutagenic. The paper is well written and comprehensively discusses the chemical properties of PAHs as well as their source apportionment techniques. In my view, it merits publication after including some further details following the comments below:
← According to your suggestion, I have revised the manuscript as follows.
1) The Introduction is focused on the health effects of PAHs and NPAHs (which is the most important topic when it comes to PAHs). However, it’s worth adding the importance of PAHs in aerosol light absorption. Studies have shown that high molecular weight PAHs are important contributors to brown carbon light absorption and NPAHs are even more efficient UV absorbers.
- doi.org/10.1080/02786826.2020.1726867
- doi.org/10.1021/acs.est.8b02386
- doi.org/10.1016/j.scitotenv.2019.135902
← Thank you very much for your kind comment. The sentence concerning the contribution of PAHs to brown carbon light absorption has been added in 1. Introduction (lines 56-57) with the latest reference [9].
2) Line 191: For better clarification, the PCA and PMF methods are known as factor analysis tools, which don’t necessarily belong to chemical mass balance category. The pure CMB method is conducted by MM-CMB. On the other hand, although PMF solves the CMB equation, the target variable is not necessarily re-constructed based on the mass of individual components (used as the input to the model), rather the relative association between normalized levels of species matters.
← According to your important comment, one sentence has been added (lines 210-211).
3) Lines 337-342: There have been studies conducted in Europe observing high levels of PAHs due to biomass burning in winter (that was higher than typical PAHs levels in east Asia, middle East, and USA).
- doi.org/10.1016/j.atmosenv.2006.12.053
- doi.org/10.1016/j.scitotenv.2020.143582
- doi.org/10.1016/j.scitotenv.2011.11.026
← According to your important comment, one sentence has been added (lines 364-365) with two references suggested [99, 100].
4) Lines 352-357: Similar to comment #3, biomass burning is also an important source of PAHs and should be added here.
← According to your important comment, the paragraph has been revised by adding one sentence (lines 391-392).
Round 2
Reviewer 1 Report
The author has revised the manuscript. However, it is still lacking scientific depth wich would be expected from a review paper.
Author Response
Thank you very much for your very kind comments. According to them, I have revised the manuscript as follows.
- Title: “outdoor and indoor” have been added.
- Introduction: Sentences concerning outdoor and indoor have been added (lines 64-66).
- Global and Local Pollution: Several sentence concerning outdoor and indoor have been added (lines 367-369, 383-387, 393-397).
- Conclusion: A sentence concerning indoor sources to PAHs and NPAHs has been added (lines 419-421).
I hope they are enough for the reviewer’s request.
