Comprehensive Analysis of PM₁ Composition in the Eastern Indo-Gangetic Basin: A Three-Year Urban Study

Round 1

Reviewer 1 Report

This study aims to understand the sources of PM1 in the Eastern Indo-Gangetic Basin. The study analyzed the water-soluble ions and metals in PM1 with a large sample size. The study provides a valuable dataset to the scientific community. Before publication, the manuscript should be reorganized and the dataset should be re-analyzed. In addition, the language should be edited by a senior expert. There are some missing descriptions in the experimental section. Please add it when the revised manuscript is submitted.

 

1.      Abstract Please re-edit the abstract. In the first sentence, highlight the purpose of the study. Then, describe the method used in this study. After the method description, please present the results and findings. Please remove the last sentence of the abstract. Lots of PM1 studies have been carried out worldwide. The implications of this study could help policymakers to formulate reduction policies in India. 

 

2.Introduction Lines 43-45 reference here

         

Lines 51-53 reference here

 

3. Lines 71-73 “For source apportionment studies of PM1, those chemical... multiple linear regression (MLR), and principal component analysis” This description is not right.

The isotopic technique could also be used in the source apportionment of PM1. There are some references for the isotopic technique. One reference should be cited here. The authors could read this publication for further information.

 

Tao, M., Q. Liu & J. J. Schauer (2022a) Direct measurement of the deposition of submicron soot particles on leaves of Platanus acerifolia tree. Environmental Science: Processes & Impacts, 24, 2336-2344. https://doi.org/10.1039/D2EM00328G

 

4. Methods section. There are some missing descriptions in the experimental section. Please add it when the revised manuscript is submitted.

 

Lines 93-106 How many PM1 samples do you collect each year? The descriptions of the sample size are not clear. 

 

Do you collect field samples? How do you collect them?

 

Additionally, how do you collect meteorological parameters?

 

5.      The measurements of metals are not clear. How do you control the quality of the metal measurements? Do you measure the field samples? How do you estimate the metal levels in PM1? Do you pre-treat the PM1 before the measurements of PM1 using ICP-OES? Do you pre-treat the PM1 before the measurements of PM1 using EDX and WD-XRF? These descriptions are vital to the publication.

 

6.      How do you measure the water-soluble ions in PM 1? Do you pre-treat the PM1 before the measurements of water-soluble ions? How do you do this experiment? One reference should be included. The authors could read this publication for further information.

Tao, M., Y. Xu, J. Gong & Q. Liu (2022b) Estimation of aerosol acidity at a suburban site of Nanjing using the machine learning method. Journal of Atmospheric Chemistry, 79, 141-151. https://doi.org/10.1007/s10874-022-09433-4

 

7.      Source apportionment of PM1. This section should be divided into two sections.

One section should include the descriptions of the Enrichment Factor analysis. Please move Lines 322-332 to this section.

The other section should include a description of PCA analysis.

 

Why do you conduct a PCA analysis using metals and water-soluble ions? The current PCA analysis with the inputs of metals does not apportion PM1 mass but the mass of metals.

 

8.      Table 2 defines the ionic ratio

 

9.      Figure 5 please re-plot Figure 5. The levels of Pb EF exceed the scale of the y-axis.

 

10.  The biggest concern is the figure 6. The source profile is not clear. I recommend the authors conduct PCA analysis with the inputs of metals and water-soluble ions together. The following sources may be apportioned, which are secondary sources, dust, mobile sources, industrial sources, and biomass burning/agricultural emissions.

 

If the authors can not revise the manuscript according to the above recommendations, there are technical drawbacks in the manuscript.

This study aims to understand the sources of PM1 in the Eastern Indo-Gangetic Basin. The study analyzed the water-soluble ions and metals in PM1 with a large sample size. The study provides a valuable dataset to the scientific community. Before publication, the manuscript should be reorganized and the dataset should be re-analyzed. In addition, the language should be edited by a senior expert. There are some missing descriptions in the experimental section. Please add it when the revised manuscript is submitted.

 

1.      Abstract Please re-edit the abstract. In the first sentence, highlight the purpose of the study. Then, describe the method used in this study. After the method description, please present the results and findings. Please remove the last sentence of the abstract. Lots of PM1 studies have been carried out worldwide. The implications of this study could help policymakers to formulate reduction policies in India. 

 

2.Introduction Lines 43-45 reference here

         

Lines 51-53 reference here

 

3. Lines 71-73 “For source apportionment studies of PM1, those chemical... multiple linear regression (MLR), and principal component analysis” This description is not right.

The isotopic technique could also be used in the source apportionment of PM1. There are some references for the isotopic technique. One reference should be cited here. The authors could read this publication for further information.

 

Tao, M., Q. Liu & J. J. Schauer (2022a) Direct measurement of the deposition of submicron soot particles on leaves of Platanus acerifolia tree. Environmental Science: Processes & Impacts, 24, 2336-2344. https://doi.org/10.1039/D2EM00328G

 

4. Methods section. There are some missing descriptions in the experimental section. Please add it when the revised manuscript is submitted.

 

Lines 93-106 How many PM1 samples do you collect each year? The descriptions of the sample size are not clear. 

 

Do you collect field samples? How do you collect them?

 

Additionally, how do you collect meteorological parameters?

 

5.      The measurements of metals are not clear. How do you control the quality of the metal measurements? Do you measure the field samples? How do you estimate the metal levels in PM1? Do you pre-treat the PM1 before the measurements of PM1 using ICP-OES? Do you pre-treat the PM1 before the measurements of PM1 using EDX and WD-XRF? These descriptions are vital to the publication.

 

6.      How do you measure the water-soluble ions in PM 1? Do you pre-treat the PM1 before the measurements of water-soluble ions? How do you do this experiment? One reference should be included. The authors could read this publication for further information.

Tao, M., Y. Xu, J. Gong & Q. Liu (2022b) Estimation of aerosol acidity at a suburban site of Nanjing using the machine learning method. Journal of Atmospheric Chemistry, 79, 141-151. https://doi.org/10.1007/s10874-022-09433-4

 

7.      Source apportionment of PM1. This section should be divided into two sections.

One section should include the descriptions of the Enrichment Factor analysis. Please move Lines 322-332 to this section.

The other section should include a description of PCA analysis.

 

Why do you conduct a PCA analysis using metals and water-soluble ions? The current PCA analysis with the inputs of metals does not apportion PM1 mass but the mass of metals.

 

8.      Table 2 defines the ionic ratio

 

9.      Figure 5 please re-plot Figure 5. The levels of Pb EF exceed the scale of the y-axis.

 

10.  The biggest concern is the figure 6. The source profile is not clear. I recommend the authors conduct PCA analysis with the inputs of metals and water-soluble ions together. The following sources may be apportioned, which are secondary sources, dust, mobile sources, industrial sources, and biomass burning/agricultural emissions.

 

If the authors can not revise the manuscript according to the above recommendations, there are technical drawbacks in the manuscript.

Author Response

1. REVIEWER-01

• Responses to the comments in Text

The following are the corrections as suggested by the respected reviewer –

1. Abstract Please re-edit the abstract. In the first sentence, highlight the purpose of the study. Then, describe the method used in this study. After the method description, please present the results and findings. Please remove the last sentence of the abstract. Lots of PM1 studies have been carried out worldwide. The implications of this study could help policymakers to formulate reduction policies in India. 

Response: We have modified the "Abstract" as per the suggestions of the reviewer (Line: 23-44).

2. Introduction Lines 43-45 reference here. Lines 51-53 reference here

Response: Thanks for pointing this out. We have now added the references in the revised manuscript (Line: 66, 75).

3. Lines 71-73 “For source apportionment studies of PM₁, those chemical... multiple linear regression (MLR), and principal component analysis” This description is not right. The isotopic technique could also be used in the source apportionment of PM₁. There are some references for the isotopic technique. One reference should be cited here. The authors could read this publication for further information.

Tao, M., Q. Liu & J. J. Schauer (2022a) Direct measurement of the deposition of submicron soot particles on leaves of Platanus acerifolia tree. Environmental Science: Processes & Impacts, 24, 2336-2344. https://doi.org/10.1039/D2EM00328G

Response: Thank you for pointing this out. We have now revised the section and added the missing reference according to the reviewer’s suggestions (Line: 94-100).

4. Methods section. There are some missing descriptions in the experimental section. Please add it when the revised manuscript is submitted.

Response: We agree, we should have been more exhaustive in experimental section, and have modified the entire ‘materials and methods’ section as mentioned by the reviewer.

Lines 93-106 How many PM₁ samples do you collect each year? The descriptions of the sample size are not clear. Do you collect field samples? How do you collect them?

 Response: Thank you for pointing this out. We have revised this section accordingly (Line: 133-157).

Additionally, how do you collect meteorological parameters?

Response: We have also revised experimental section containing meteorological parameters and updated it, as suggested by reviewers (Line: 172-175).

5. The measurements of metals are not clear. How do you control the quality of the metal measurements? Do you measure the field samples? How do you estimate the metal levels in PM₁? Do you pre-treat the PM₁ before the measurements of PM₁ using ICP-OES? Do you pre-treat the PM₁ before the measurements of PM₁ using EDX and WD-XRF? These descriptions are vital to the publication.

Response: We agree, metal measurements section needs further elaboration. As per the reviewer's suggestion, we have revised the section (Line: 203-237). In addition, we have made some modifications to address the concern raised by one of the learned reviewers regarding the confusion caused by presenting both WD-XRF and ICP-OES results for the same sample. In order to avoid any confusion, we have removed the WD-XRF result from our dataset. As the ICP-OES technique has better sensitivity and lower detection limits compared to the XRF method. Moreover, it also has a lower error rate to detect lower-concentration elements present in PM1. Therefore, we opted for ICP-OES over XRF for PCA analysis.

6. How do you measure the water-soluble ions in PM₁? Do you pre-treat the PM₁ before the measurements of water-soluble ions? How do you do this experiment? One reference should be included. The authors could read this publication for further information.

Tao, M., Y. Xu, J. Gong & Q. Liu (2022b) Estimation of aerosol acidity at a suburban site of Nanjing using the machine learning method. Journal of Atmospheric Chemistry, 79, 141-151. https://doi.org/10.1007/s10874-022-09433-4

Response: We have revised this section, added a detailed procedure for measuring water-soluble ions, and included the mentioned reference (Line: 238-255).

7. Source apportionment of PM₁. This section should be divided into two sections. One section should include the descriptions of the Enrichment Factor analysis. Please move Lines 322-332 to this section. The other section should include a description of PCA analysis.

Response: We have divided ‘Source apportionment of PM₁’ into following two sections- i) Enrichment Factor analysis ii) PCA analysis and included the description in the methodology section, as suggested by the reviewer (Line: 261-283).

Why do you conduct a PCA analysis using metals and water-soluble ions? The current PCA analysis with the inputs of metals does not apportion PM1 mass but the mass of metals.

Response: In order to identify the main sources affecting the aerosol composition at the site the PCA analysis was conducted using only the metal data. The PCA analysis helped to identify/locate the probable sources of metals which contributing in PM₁ mass concentration. As per the literature, the metal data can be used for the source apportionment of particulate matter over a region. Both the results of ICP-OES and ion chromatograph were taken for PCA analysis (Line: 275-283).

8. Table 2 defines the ionic ratio

Response: We have defined the ionic ratio in table 2 (Line: 565).

9. Figure 5 please re-plot Figure 5. The levels of Pb EF exceed the scale of the y-axis.

Response: Thank you for the comment. The graph has been re-plotted and updated in the revised manuscript (Line: 620).

10. The biggest concern is the figure 6. The source profile is not clear. I recommend the authors conduct PCA analysis with the inputs of metals and water-soluble ions together. The following sources may be apportioned, which are secondary sources, dust, mobile sources, industrial sources, and biomass burning/agricultural emissions.

Response: Thank you for the suggestion. The PCA analysis was conducted again using the metal and ions data of PM₁ and updated in revised manuscript (Line: 664).

Author Response File: Author Response.pdf

Reviewer 2 Report

This study encompasses the monitoring and elemental characterization of PM1 over a consecutive three-year period within an urban sprawl situated in the eastern Indo-Gangetic Basin. In the present study, the authors tried to understand the physico-chemical characteristics and emission source apportionment of PM1 over an urban sprawl in the Indo-Gangetic Basin. The authors applied the principal component analysis technique to identify the emission sources of PM1. The three monitoring sites were selected for PM1 collection. The methods used in this study are, in general, adequate and acceptable.

This manuscript is an interesting attempt to analyze PM1 composition in the Eastern Indo-Gangetic Basin and relate it to emission source apportionment of PM1 over an urban sprawl in the basin. Therefore, this issue merits publication in Sustainability. However, there are some minor points that the authors should address before this manuscript is suitable for publication.

1. The location of the meteorological station should be indicated in Fig. 1.
2. Subsections 2.2 and 2.3 contain similar topics. Therefore, both subsections can be combined.
3. It is also necessary to give a detailed explanation of the topography of the region.

Comments for author File: Comments.docx

Author Response

I wanted to express my sincere gratitude for the insightful and constructive feedback you provided on the manuscript. Your comments and suggestions were incredibly valuable in refining and enhancing the content.

I am pleased to inform you that all the feedback has been carefully considered and incorporated into the revised manuscript. Your expertise has significantly contributed to the improvement of the overall quality and coherence of the work. Your detailed observations were particularly instrumental in addressing specific areas that needed attention.

Thank you once again for your time, effort, and dedication in reviewing the manuscript. Your contribution has been invaluable, and I truly appreciate your commitment to ensuring the quality of this work.

Best regards,

Author Response File: Author Response.pdf

Reviewer 3 Report

Review report

 

-Page3, Lines 115-116:The main focus is to understand the characterization of small-size PM, hence in this study, large fractions were not eliminated.

This sentence is not clear, we can't understand how keeping the large fractions can help to understand the characterization of the small size of PM???

More explanations are needed.

 

-  Page3, Lines 152-158:

Ø You have used two different techniques WDXRF and ICP-OES, to quantify the same elements for example As was measured by WDXRF and ICP-OES, idem for Fe, Mg, Zn, etc...

What exactly was the goal of using two techniques to quantify the same elements!!!!

Ø Can you give more details about the sample preparation used to analyze the PM1 filter by WDXRF and ICP-OES:

For WDXRF, the filters were analyzed directly without sample preparation?

For ICP-OES, for this technique the samples should be liquid, so which procedure have you adopted for filter digestion?

These details are essential to include in the Materials and Methods Section.

Ø Have you use any Standard Reference Materials (SRM) for quality control of the obtained results? If yes, please precise.

 

-  Table 1:

Ø What represent the letters (a, b and c) added as suffix in front of each number?

 

-  Figures 3D, 4A and 4B:

Ø What represent the letters (a, b and c) added in the top of histograms??

 

-  If we compare the WD-XRF values reported in Figure 4A, with the ICP-OES values reported in Figure 4B, there are signficant differences between the techniques, for the almost analyzed elements, the WD-XRF concentrations are higher than those ICP-OES concentrations.

Ø How do you explain this difference,

Ø And what is the objective of analyzing the same elements with the two techniques and presenting the results of these 2 techniques in the 2 differents Figures?

Ø In the text, you have discussed separtely the results obtained with each technique, and the problem is that there are some contradictions between the results obtained with the techniques for the same list of elements.

Ø The authors should give more explanations ???

 

-   Section 3.5 (Enrichment factor analysis):

Ø The authors have gived for each list of elements, a list of potential emission sources, for example for Fe, the authors says: “Mn and Ni 336 appeared to be intermediately enriched because their EF values ranged from 10 to 100 and they may 337 have originated from fuel combustion, metal smelting, coal combustion, and other industrial 338 processes”.

This is a general list of potential emission sources of Mn and Ni, the authors have to precise the potential emission sources of Mn and Ni that are really present or that exist in their study site.

 

-  Section 3.6 (Principle Component Analysis):

Ø On what basis, you have choise to use the ICP-OES results to carry-out the PCA, and not the WDXRF results?

 

- Discussion Section:

 

Ø To summarize, I recommend that the authors not discuss the results separately, as it was done in the ‘Results Section’, the better is to combine all the results obtained from the different techniques and statistical analysis and discuss them all together.

Please refer to the attached PDF file for More comments.

Comments for author File: Comments.pdf

Author Response

Responses to the comments in Text

The following are the corrections as suggested by the respected reviewer –

 

1. Page3, Lines 115-116: The main focus is to understand the characterization of small-size PM, hence in this study, large fractions were not eliminated. This sentence is not clear, we can't understand how keeping the large fractions can help to understand the characterization of the small size of PM??? More explanations are needed.

Response: Apologies, this was a mistake. We have deleted it in revised manuscript.

2. Page3, Lines 152-158:

Ø You have used two different techniques WDXRF and ICP-OES, to quantify the same elements for example As was measured by WDXRF and ICP-OES, idem for Fe, Mg, Zn, etc... What exactly was the goal of using two techniques to quantify the same elements!!!!

Response:  After comparing the results of WD-XRF and ICP-OES techniques for the same sample, we have decided to present the data of ICP-OES only to avoid confusion. As the ICP-OES technique has better sensitivity and lower detection limits compared to the XRF method. Moreover, it also has a lower error rate to detect lower-concentration elements present in PM1. Therefore, we opted for ICP-OES over XRF for PCA analysis.

 

Ø Can you give more details about the sample preparation used to analyze the PM1 filter by WDXRF and ICP-OES: For WDXRF, the filters were analyzed directly without sample preparation? For ICP-OES, for this technique the samples should be liquid, so which procedure have you adopted for filter digestion? These details are essential to include in the Materials and Methods Section.

Response: We have revised and updated the material and method section, as mentioned by the reviewer. We have updated the detailed procedure of ICP-OES (as we have deleted the WD-XRF result in the revised manuscript) (Line: 230-237).

 

Ø Have you use any Standard Reference Materials (SRM) for quality control of the obtained results? If yes, please precise.

Response: Multi-element standard solution (Cat No. 111355 & 109487) was used for QA/QC. We have updated this in revised text (Line: 237).

 

3. Table 1:

Ø What represent the letters (a, b and c) added as suffix in front of each number?

 Response: In Table 1, different letters indicate seasonal variation (significant or non-significant) among all studied meteorological parameters in each study year according to Duncan’s test at p < 0.05.

 

4. Figures 3D, 4A and 4B:

Ø What represent the letters (a, b and c) added in the top of histograms??

 Response: In figure 3D, different letters indicate variation (significant or non-significant) among all elements according to Duncan’s test at p < 0.05.

In figure 4A & 4B, different letters indicate seasonal variation (significant or non-significant) among all elements according to Duncan’s test at p < 0.05.

 

5. If we compare the WD-XRF values reported in Figure 4A, with the ICP-OES values reported in Figure 4B, there are significant differences between the techniques, for the almost analysed elements, the WD-XRF concentrations are higher than those ICP-OES concentrations.

Ø How do you explain this difference

Ø And what is the objective of analyzing the same elements with the two techniques and presenting the results of these 2 techniques in the 2 different Figures?

Ø In the text, you have discussed separately the results obtained with each technique, and the problem is that there are some contradictions between the results obtained with the techniques for the same list of elements.

Ø The authors should give more explanations???

Response: We acknowledge that the results of both WD-XRF and ICP-OES analyses of the same sample may have caused confusion. With all due respect to the suggestion made by the respected reviewer, we have finally decided to present the data of ICP-OES only. As, the ICP-OES technique has better sensitivity and lower detection limits compared to the XRF method. Moreover, it also has a lower error rate, detecting lower concentration elements present in PM1. Therefore, we opted for ICP-OES over XRF for PCA analysis.e XRF method. And it has also lower error rate, to detect lower concentration elements present in PM1. Therefore, we opted for ICP-OES over XRF for PCA analysis.

6. Section 3.5 (Enrichment factor analysis): The authors have gived for each list of elements, a list of potential emission sources, for example for Fe, the authors says: “Mn and Ni 336 appeared to be intermediately enriched because their EF values ranged from 10 to 100 and they may 337 have originated from fuel combustion, metal smelting, coal combustion, and other industrial 338 processes”. This is a general list of potential emission sources of Mn and Ni, the authors have to precise the potential emission sources of Mn and Ni that are really present or that exist in their study site.

Response: We agree with the reviewer. This section has been modified and specified, as per reviewer’s suggestion (Line: 578-579).

 

7. Section 3.6 (Principle Component Analysis): On what basis, you have choice to use the ICP-OES results to carry-out the PCA, and not the WDXRF results?

Response: Thank you for the comment, The ICP-OES technique has better sensitivity and lower detection limits compared to the XRF method. And it has also lower error rate, to detect lower concentration elements present in PM1. Therefore, we opted for ICP-OES over XRF for PCA analysis.

 

8. Discussion Section: To summarize, I recommend that the authors not discuss the results separately, as it was done in the ‘Results Section’, the better is to combine all the results obtained from the different techniques and statistical analysis and discuss them all together.

Response: We have combined result and discussion in revised manuscript, as suggested by the respected reviewer (Line: 296-724).

 

 

ADDITIONAL REVISIONS

Please refer to the attached PDF file for More comments.

Response: We have also revised the manuscript as per the corrections mentioned in the pdf.

1. ‘Smaller-size’ replaced with ‘small’ (Line: 66).
2. Additional citations have been added in the sentence ‘causes the most deleterious health impacts [2]’ (Line: 72).
3. ‘came to the conclusion’ replaced with ‘concluded’ (Line: 89).
4. The sentence ‘PM₁₀, PM₅ and PM₁’ has been modified (Line: 91).
5. ‘vehicle exhausts and agriculture’ replaced with ‘vehicle exhausts, and agriculture’ (Line: 92).
6. We have revised the sentence ‘data has frequently’ and modified it (Line: 94-97).
7. ‘fulfil’ replaced with ‘fulfill’ (Line: 113).
8. ‘The finding’ replaced with ‘The findings’ (Line: 114).
9. ‘in accordance with’ replaced with ‘according to’(Line: 120).
10. ‘At’ has been removed (Line: 131).
11. ‘distance’ replaced with ‘distances’ (Line: 132).
12. ‘away’ replaced with ‘away from’ (Line: 132).
13. ‘polytetrafluroethylene’ replaced with ‘polytetrafluoroethylene’ (Line: 140).
14. The section ‘1m’ has modified (Line: 141).
15. The section ‘Filter’ has modified (Line: 143).
16. ‘prior to’ replaced with ‘before’ (Line: 143).
17. ‘the filters’ replaced with ‘filters’ (Line: 144).
18. The section ‘using Harvard’ has removed.
19. ‘prior to’ replaced with ‘before’ (Line: 145, 149).
20. The sentence " The main focus is to understand the..." has been removed.
21. ‘filter based’ replaced with ‘filter-based’ (Line: 175).
22. The sentence "Wavelength dispersive X-Ray..." has been removed.
23. ‘component’ replaced with ‘components’(Line: 238).
24. ‘in order to’ replaced with ‘to’ (Line: 275).
25. ‘condition18’ replaced with ‘condition [22]’ due to change in reference number (Line: 277).
26. The section ‘the data’ has removed.
27. The section ‘PM1 sample’ has removed.
28. ‘minimum and maximum’ replaced with ‘minimum, and maximum’ (Line: 290).
29. ‘on the basis’ replaced with ‘based on’ (Line: 292).
30. ‘with average wind speeds’ replaced with ‘with an average wind speed’ (Line: 307).
31. ‘Overview of PM1 concentration’ replaced with ‘Overview of PM1 concentrations’ (Line: 325).
32. The sentence with ‘Despite the fact that’ has removed.
33. The sentence with ‘clearly’ has removed.
34. The sentence with ‘with the exception of’ has removed.
35. The section ‘analysis of PM1 that include…’ has been removed.
36. ‘to measure that how’ replaced with ‘to measure how’ (Line: 265).
37. ‘to the targeting element and’ replaced with ‘to the targeting element, and’ (Line: 269).
38. ‘indicate’ replaced with ‘indicates’ (Line: 269).
39. The sentence ‘EF values were found to less’ has modified (Line: 580).
40. ‘that natural source’ replaced with ‘that a natural source’ (Line: 581).
41. ‘component’ replaced with ‘components’ (Line: 632).
42. ‘data..’ replaced with ‘data.’ (Line: 633).
43. ‘interrelation’ replaced with ‘the interrelation’ (Line: 671).
44. This sentence ‘the 24h’ has removed because of repetition.
45. ‘lowering of mixing height over the region’- The authors should confirm that the mixing height over the region is really low by calculating it and checking if there is a significant correction between the mixing height and the PM1 concentrations during the post-monsoon.

Thank you for the comments. There are several reasons why mixing height changes like local meteorological, geographic factors, etc. However, there are some general observations of mixing height with respect to the different seasons. In general, Due to decreased solar heating, drier air, cooler nights, and changes in weather patterns, mixing height is often low in the post-monsoon season. These variables provide stable atmospheric conditions that can have an impact on air quality and pollution dispersion by reducing vertical mixing and resulting in narrower mixing layers. Lower mixing heights limit the vertical dispersion and dilution of pollutants, including PM, near the surface. As a result, PM particles emitted from various sources are more likely to become trapped within the restricted mixing layer. This can lead to the accumulation of PM near the ground, resulting in higher PM concentrations.

There are several methods that may be used to calculate and estimate mixing height like Lidar, Sodar, remote sensing, etc., however, in the present manuscript, it is mentioned only to support the results of why the PM seems too high in the post-monsoon season.

We have also mentioned this in text (Line: 335-339).

46. ‘high in’ replaced with ‘high on’ (Line: 347).
47. ‘spherical, has’ replaced with ‘spherical and has’ (Line: 399).
48. ‘emits’ replaced with ‘is emitted’ (Line: 401).
49. ‘sulphur’ replaced with ‘sulfur’ (Line: 535).
50. The section ‘In order to confirm plausible local sources’ has modified and removed.
51. ‘Tyre’ replaced with ‘tire’ (Line: 453).
52. ‘Fe, Mn, Ni, Zn’ replaced with ‘Fe, Mn, Ni, and Zn’ (Line: 456).
53. ‘origin of metals’ replaced with ‘origins of metals’ (Line: 457, 458).
54. ‘(i.e. 1.4 vs 0.3)’ replaced with ‘(i.e. 1.4 vs. 0.3)’ (Line: 543).
55. ‘is approx’ replaced with ‘approximately’ (Line: 553-554).
56. ‘Zn/Pb ratio’ replaced with ‘the Zn/Pb ratio’ (Line: 554).
57. ‘Zn/Al ratio’ replaced with ‘the Zn/Al ratio’ (Line: 557).
58. ‘state highway’ replaced with ‘State Highway’(Line: 702).
59. ‘could be a significant source’ replaced with ‘could be significant sources’(Line: 717-718).
60. The sentence ‘Al and Fe’ has been modified and removed.
61. ‘In order to’ replaced with ‘to’ (Line: 857).
62. ‘concentration’ replaced with ‘concentrations’ (Line: 860).
63. ‘with K having’ replaced with ‘with K, having’(Line: 867).
64. The sentence ‘higher the surface’ has been removed.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Accept

Author Response

Thank you very much for your kind consideration.

Reviewer 3 Report

The authors have answered all the questions and all the recommendations were taken into consideration.

I have no more comments.

Author Response

Thank you very much for your kind appreciation.