Dear Authors,

Please respond to review's comments. It is critical that the manuscript become less descriptive and include a more developed scientific discussion. The referee has provided some suggestions.

Best,
Sally Pusede

Dear authors,

The manuscript is improved, but please address the concerns below prior to publication.

The Introduction does not properly frame the analysis. As I understand it, the manuscript describes an application of CCM to regional-scale relationships between PM2.5 and meteorological variables and discusses these results in the context of previous statistical approaches. There is no need for elementary detail on PM2.5 health effects or on trends in pollutants other than PM2.5 (e.g., ozone), especially outside of China. Focus the introductory content on material relevant to the manuscript, especially research on PM2.5-meteorology relationships in China. The CCM method should be introduced, since application of CCM is the heart of the work. The paragraph summarizing past work on PM2.5-meteorology correlations needs to be edited (begins line 104). The first two sentences are unnecessary, replace them with a sentence summarizing what has been observed so the reader is not presented with a listing of past results without context. I encourage you to add a concluding paragraph to the Introduction that describes the analysis that follows.

I am not familiar with meteorological measurement evaporation. Please clarify. The footnote is not helpful and is not encouraged in ACP.

The meteorological variables should not be italicized.

Line 157: Write out the word “minimum.”

Variable abbreviations like meanTEM and maxPRS reduce readability, rather than improve it. I recommend they are all removed.

Page 6: Footnotes should be avoided. Place the information in the main text.

Line 175: Remove etc., instead begin the list with “e.g.”

Line 234: Say where.

Avoid use of the word “prove.”

Remove all uses of the word “haze.” Be specific, if you mean PM2.5, say that.

The first sentence of many paragraphs in the paper is superfluous and should be deleted to improve readability.

Fig. 1: Use full titles and full axis labels so the figure is more easily read.

Fig. 1: Explain why these four panels were selected.

Line 300: This entire paragraph can be deleted.

Figs 2 will not reproduce well. It is difficult to distinguish the gray scale. The gray scale limits should be rounded to integers. I recommend the wind roses be made larger and the legends labeled with words rather than abbreviations.

Figs 2 and 3: Remove the map inset and the yellow dashed boundary. These do not contribute the display of the data.

Line 323: This paragraph is too vague. You are reporting on your quantitative analysis here. This text is too general and could be known without your CCM results.

Line 331: Same comment. This paragraph is too vague. You are reporting on your quantitative analysis here. This text is too general and could be known without your CCM results.

Line 340: Same comment. This paragraph is too vague. You are reporting on your quantitative analysis here. This text is too general and could be known without your CCM results.

Line 352: This entire paragraph can be deleted.

Line 366: Likewise, points a–c are quite general. Can you talk about these results in specific quantitative terms?

Fig. 3: Same comments as on Fig 2. Can you make these figures more readable? Is the size of the symbol important? They appear to vary.

Line 458: Do you mean “across different regions?”

Lines 486–488: What is the evidence for this?

Line 532: Much of the content of this paragraph appears to be irrelevant to the manuscript.

The Discussion should be refocused. The purpose of this analysis was to apply CCM to a wide region. The Discussion should then consider the difference between the author’s CCM results and past analyses on more local areas and to compare CCM to other statistical approaches. First, it is well known that PM2.5 correlates with meteorological variables. Second, ACP is not an appropriate journal to expound upon government policies and public response unrelated to analysis perform. These are not the discussion point, instead the authors must answer:

What new do we learn about PM2.5-meteological relationships by using CCM over a large spatial region?

Best,
Sally Pusede

Dear authors,

Thank you for your careful revisions. I have the following minor comments prior to publication.

Line 286: write out meanRHU and maxWIN. Write out other instances as well.

The organization with letter labeling (a., b., c.) should be changed to better adhere to ACP style conventions.

I appreciate the quantitative results added to the Results section. The section is now quite long, I recommend either removing rho values inessential to the main points, or adding a table to display the values to improve readability.

Is Fig. 4 necessary? it appears to provide the same in formation as Table 1.

The manuscript would benefit from a thorough proofreading.

Line 539: PM2.5

I recommend the Discussion section be edited to be made slightly more concise, if possible.

Best,
Sally Pusede