Unveiling PM_2.5 Transport Pathways: A Trajectory-Channel Model Framework for Spatiotemporally Quantitative Source Apportionment

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The article "Unveiling PM2.5 Transport Pathways: A Trajectory Channel Model Framework for Spatiotemporally Quantitative Source Approximation" presents a new promising method that develops CWT analysis to study the spatiotemporal dynamics of atmospheric pollution using the example of PM2.5. The method combines high-resolution atmospheric modeling using the WRF model and a 72-hour reverse trajectory analysis, which makes it possible to accurately identify sources of pollution and key transport routes. The application of the method in four cities of the Yangtze Delta has shown that the new model provides higher accuracy and resolution compared to traditional approaches. The method makes it possible to quantify the contribution of regional sources and reconstruct the processes of transport of pollutants in the atmosphere. This makes it possible to effectively manage air quality and develop pollution reduction measures. I believe that the manuscript should be published in the journal atmosphere, after clarifying some inaccuracies. 

• Line 34. I suggest the authors think about the keywords of the article. WRF-NAQPMS model -> WRF-NAQPMS; Trajectory channel transport model (TCTM) -> split into two: Trajectory channel transport model and TCTM; pollution channel -> air pollution; + CWT (although I believe that a change in keywords will help in the search for your article, this remark is entirely at your discretion the author);
• Line 46-47. The above list does not include HYSPLIT, AERMOD, which are widely used both to assess the dispersion of emissions from sources (using a dispersion unit), and to assess the movement paths of air masses and identify likely sources of atmospheric pollution, including during periods with extremely high concentrations (Shikhovtsev, M. Y., Molozhnikova, Y. V., Obolkin, V. A., Potemkin, V. L., Lutskin, E. S., & Khodzher, T. V. (2024). Features of Temporal Variability of the Concentrations of Gaseous Trace Pollutants in the Air of the Urban and Rural Areas in the Southern Baikal Region (East Siberia, Russia). Applied Sciences, 14(18), 8327.). These models are also used to calculate the trajectories of air masses, for use in receptor modeling methods (CWT, PSCF, SQBA, CFA and others). 
• Line 95. Can your proposed model apply only data derived from the WRF-NAQPMS model (or another version of the WRF model)? Do I understand correctly that this is what primarily determines the higher accuracy of the TCTM model (compared to the CWT and PSCF methods)?
• Line 100. Use lowercase to write PM2.5. 
• Line 103. Please specify which model was used to generate the reverse trajectories? WRF- NAQPMS? How much is this information needed in the "Introduction" chapter? Traditionally, such information is placed in the chapter "Materials and methods". For example, leave this information only on line 138. 
• In the chapter materials and methods, the parameterization scheme of the WRF model used should be more clearly indicated, especially describing the atmospheric boundary layer (Shikhovtsev, A. Y., Kovadlo, P. G., (2023). Simulating atmospheric characteristics and daytime astronomical seeing using Weather Research and Forecasting Model. Applied Sciences, 13(10), 6354.).
• For which final heights was the calculation of the reverse trajectories carried out? (selection and justification of the choice)
• I ask you to decide on the spelling of "Equation", since the text of the manuscript contains both uppercase (181) and lowercase (178) letters. In addition, I did not find any mention of equations 1, 2, and 7-11 in the manuscript.
• Also decide on the spelling of "Concentration Weighted Trajectory" (219). There are several variants in the manuscript: line 76. Duplicate CWT and PSCF decryptions must be removed on line 218-219. 
• The materials and methods do not indicate where the authors obtained information about the content of PM2.5. Are these observations by the authors? Or surveillance from the state monitoring network? In the first case, it is recommended to specify the device, method and measurement error. 
• Line 244. Do you have data on how often such pollution episodes are recorded in the study area? How intense are they? 
• Line 255. Fix "figure 2b-f"

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

The data presented correspond to the subject of the Journal, and the article can be recommended for publication after minor revision.

 

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors In the line 100 The word PM2.5 must be in the same format as the others, the smaller 2.5

In the line 255 the letter F must be capitalized, not lowercase.

I suggest doing another example resolution to identify a source based on the reverse trajectories. No source is mentioned in the writing, that would help a lot to reinforce the model.

Great work, congratulations first of all, it shows a lot of effort and work.

       

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I have no more comments. Thanks to the authors.