Influence of Transboundary Pollution on the Variability of Surface Ozone Concentrations in the Desert Southwest of the U.S.: Case Study for Arizona

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Title: Influence of transboundary pollution on the variability of surface ozone concentrations in the Desert Southwest of the U.S.: Case Study for Arizona

 

In the manuscript, the authors have reported the influence of transboundary pollution on the variability of surface ozone concentrations at six monitoring sites in Arizona from 2017 to 2021 using hourly back-trajectories and O₃  concentration data. There are little study results on the influence of transboundary O₃  pollution on the variability of surface ozone concentrations at sites in Arizona. and, thus, this study result is an important one. Also, the data and analysis procedure sound reasonable. However, data interpretation on local profile of O₃ is weak, just reporting the levels of n the influence of transboundary O₃  pollution and comparing them with the existing study results along with a concentration-weighted trajectory (CWT) analysis. Thus, I suggest the authors add more discussions, for example, the levels of VOCs and NOx derived from prior studies at studying sites in Arizona and compared with those with those areas including the sites in California. Also, it might be interesting to discuss on the impacts of meteorological major factors including rainfall, and humidity on the variability of surface ozone concentrations at sites in Arizona. At present form, the manuscript is not suitable for publication in the Journal and I recommend the authors revised the manuscript and resubmit it.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Authors took data from various sources and conducted series of Hysplit hourly back trajectories in order to determine from where the O3 might me arriving in Arizona. Results are divided into five seasons. They found that O3 concentrations are influenced by long-range transport in spring and dry summer. The topic is interesting; however I miss here depicting the novelty. It should be depicted in Introduction and in discussion too. Moreover, Introduction part should be rewritten.

 

lines 33-35: write more clearly. Sunlight is only needed for photostationary reduction of NO2 with release of O3

line 50: write more clearly "owing to concerns over visibility and public health" - does not sound good

line 56, 69: write better English

line 70: transport of what? NOx?

line 79-82: Is this what you will do here, or why do you mention that?

Introduction: should be carefully rewritten. English is not really good at many parts. In addition, you jump from one topic to another without any explanation and interconnection. You should write here more about the effect of O3 on vegetation. Stating at line 32, that is has only "adverse effect" is too simplified. You should go into more detail, that it decreases the yield of crops, timber, reduced carbon uptake etc. See paper 10.3390/atmos12010082 reviewing the effects on vegetation. You can add that here.

line 322: low temperature has not effect on ozone formation. It can be formed even on a snow, when lot of NO2 and VOCs are present.

Conclusion: missing, write short conclusion

Comments on the Quality of English Language

Introduction should be checked.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The authors conducted a concentration-weighted trajectory (CWT) analysis using five years (2017-2021) of hourly back trajectory and ozone concentration data to identify ozone transport pathways and potential source regions at six monitoring sites in Arizona.

1.The novelty of the paper should be described in the introduction. 

2.In the introduction, it is clear that the authors do not have enough information on the existing studies and suggest that the authors should look into more studies on evolutionary algorithms and models done by others.See for example "Multi-objective optimal dispatch strategy for power systems with Spatio-temporal distribution of air pollutants"

3.The authors used the CWT model,why not combine it with PSCF for potential source analysis.

4.Recommending that the authors of 3.2.1-3.2.5 add a monthly view.

5.The authors need to add a discussion section to explain their new ideas and findings.

6.The conclusion section is missing. This is the main problem.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

accept

Reviewer 3 Report

Comments and Suggestions for Authors

Recommendation for direct acceptance.