Is There a Formaldehyde Deficit in Emissions Inventories for Southeast Michigan?

Round 1

Reviewer 1 Report

See the attached review.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

In this manuscript, the authors attempted to demonstrate that a significant amount of primary HCHO emissions are missing in a bottom-up inventory and quantify the impact of missing HCHO emissions on air quality assessment for the Southeast Michigan area.  Overall, the manuscript is easy to follow.  The topic is also appropriate for the readership of the journal. 

However, information and evidence provided in the manuscript do not seem to be sufficient to support the claims made by authors.  One of major deficiencies is a lack of solid discussions about performance evaluations for meteorological modeling and photochemical modeling.  In addition, the study design needs some improvements.  Therefore, I recommend that this manuscript be published after addressing issues/comments that are provided below.  This warrants a major revision to the manuscript. 

 

General Comments

The authors need to clarify if the findings of this study are only applicable to the study area or not because the journal is an international journal.  If the study findings are locally specific, the manuscript is recommended for publication in other journals that are more local.

The authors need to provide model performance information about meteorological modeling. 

The authors should present and discuss CAMx model performance for CO.

 

Specific Comments

Lines 51-53: The sated claim should be supported with one or more references:

Line 58: “[8[” should be “[8]”.

Lines 165-167: It is highly recommended that the SPECIATE database is also looked into for comparison.

Line 245: Why was July 12 chosen? I suggest that the authors pick a date showing high observed formaldehyde concentrations.

Line 313: “Figure 8” should be “Figure 9.”

Line 315: Why was June 18 chosen?

Lines 329-330: I recommend that the authors present MPE results first before discussing other findings because the strength of claims and findings depends on the soundness of model performance.  It is also critical to evaluate the model performance for CO since CO is used as the basis of emission adjustments for HCHO.    

Lines 335-339: To me, what authors found out indicates that the study area is NOx-limited.  If the authors do not agree with me, please provide explanations.  Additional information is important because the authors claim that HCHO control can be more effective than NOx control in the latter part of the manuscript.

Lines 342-343: What the author claimed is arguable because “significant” is somewhat subjective.  For example, 1 ppb is used as the significant impact level for air permitting purpose in US. 

Lines 345-347: The authors are highly encouraged to examine HCHO data from satellites such as TROPOMI.

Lines 385-388: The authors need to provide specific evidence for the claim beyond Figure 9 because Figure 9 is just showing differences.  Over 1 ppb differences in ozone can happen where predicted ozone concentrations are much lower than the NAAQS level. 

Lines 395-399: This is a major claim of this study. The author should provide much more specific information/evidence for this claim.  It should be noted that what the authors claim can be area specific while it can be controversial (please see my comment for Lines 335-339 above.)  Therefore, I expect that the authors clarify if the claim is for the study area or in general.

Table 3: The authors should add modeling results to the table and discuss comparison between observations and modeling results. 

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The paper is very interesting and comprehensive in its present form. It showed HCHO emissions deficit using actual measured data against the model.

I just want to comment on why there was no conclusions and recommendations derived from the study? It seemed incorporated in the discussion section. However, I would suggest having a separate conclusion and recommendation sections in this paper.

Overall, I found the paper very suitable for publication in the Atmosphere journal.

Author Response

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Author Response File: Author Response.docx

Reviewer 4 Report

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Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

I'm satisfied with the authors' response to the review comments and revised manuscript.

Reviewer 2 Report

I don't have any further comments.

Reviewer 4 Report

Good editing.