An Empirical Analysis of the Aircraft Emissions by Operating from Scheduled Flights within the Domestic Market in Spain
Alberto Baldelli
Round 1
Reviewer 1 Report
The paper evaluates the CO2 emissions of flights within Spain. The idea of the study is very interesting, and I am looking forward to the other papers being planned by the author.
Major comments:
- Abstract: If this is the most specific you can be about your results, then leave the abstract as it is. However, if you can be more specific, then please do so.
- Add a figure of the methodology as without this it is sometimes a bit confusing.
- You mention the contribution of the paper however it would be appropriate to be more specific by formulating some further research questions at the beginning of the paper and then answer these towards the end of the paper.
Minor:
- Please fix the “Error! Reference source not found.”
- Can you add to table 2 the “Average Annual Passenger Traffic”.
- When I read the beginning of the paper, I would have liked to see a map with the flights at the start of the methodology. You have a map of the flights later in the paper.
- Table 5, is the row entitled as a total? However, 564 is probably not the total, is it the average of the km?
- If possible, it might be a good idea to add an estimation of all flights within Spain? Or all 'very' short flights within Spain?
Author Response
Dear Reviewer:
Manuscript ID: processes-2223824
Title: “An Empirical Analysis of the Aircraft Emissions by Operating from Scheduled Flights within the Domestic Market in Spain”
We are deeply grateful for your efforts and suggestions for our manuscript. They have been of great help in revising and improving our paper and have been an important guide to our research. The following is a point-by-point response to your comment, and the response is in red. The modified version has also been marked in red.
Faithfully,
The Authors.
Comments and Suggestions for Authors
The paper evaluates the CO2 emissions of flights within Spain. The idea of the study is very interesting, and I am looking forward to the other papers being planned by the author.
Major comments:
- Abstract: If this is the most specific you can be about your results, then leave the abstract as it is. However, if you can be more specific, then please do so.
Response: Thank you for pointing this out. However, this is the most specific we can be about our results due to the complexity of the research subject, the large scope of routes to be gathered for the emission estimations, as well as the wide variety of aircraft operated by each carrier on each flight. Nevertheless, results have been displayed in the section of Results through many maps and relevant figures, and findings have been thoroughly discussed in the section of Discussion.
- Add a figure of the methodology as without this it is sometimes a bit confusing.
Response: We agree with the reviewer’s assessment. Accordingly, we have revised the part of the Conceptual Research Framework by adding two figures to summarize the analysis methodology: the first concerns the data sources; the second concerns the research design. Please see the revised manuscript.
- You mention the contribution of the paper however it would be appropriate to be more specific by formulating some further research questions at the beginning of the paper and then answer these towards the end of the paper.
Response: The relevance of this study has been described by introducing the main research question in the section of Conceptual Research Framework, and then in the section of Conclusions. Please see the revised manuscript.
Minor:
- Please fix the “Error! Reference source not found.”
Response: A cross-reference had not been well-linked. The error has already been fixed.
- Can you add to table 2 the “Average Annual Passenger Traffic”.
Response: Thank you for the suggestion. But unfortunately, the Average Annual Passenger Traffic of each airport cannot be added to Table 1, since this does nothing for the study findings. As already explained in the manuscript, the research approach has been carried out through the simplification of the scope of the analysis by identifying the five busiest airports according to AENA’s database. Thus, the present study has focused on those domestic flights operating from such five representative air facilities instead of calculating passenger traffic of the 48 air facilities (46 airports + 2 heliports) belonging to AENA’s network. Furthermore, for those, not AENA owned, up to a total of a further five airports, there are no public traffic databases from trusted sources.
- When I read the beginning of the paper, I would have liked to see a map with the flights at the start of the methodology. You have a map of the flights later in the paper.
Response: Thanks for your comment. A map has been included for a better understanding of the routes analyzed in the study based on properly calculated magnitudes.
- Table 5, is the row entitled as a total? However, 564 is probably not the total, is it the average of the km?
Response: Thank you for pointing this out. The word “Total" has been replaced by “Average Distance Traveled (km)”.
- If possible, it might be a good idea to add an estimation of all flights within Spain? Or all 'very' short flights within Spain?
Response: Thank you for your comment on this matter. In the period under review, the research has been carried out mainly based on the primary source of domestic flights in Spain from the public airport network operator (AENA) by considering those flights among airports that have less than 10 operations. That is, this approach is not an estimation, but an overall analysis of all flights under such a criterion operating from the five busiest airports in the Spanish internal market. Thus, the study has not been carried out on the basis of distance but on the fact that they belong to Aena’s network in terms of accessibility and uniformity of the data.
That is, very short flights have been considered as part of short-haul routes as being shorter than 600–800 nmi (1,100–1,500 km). In any case, only flights from the Spanish mainland to the Canary Islands can be considered as medium-haul flights. Please see the part of Conclusions.
I hope all the efforts to improve the manuscript from your comments can meet the high expectations of the journal.
The Authors,
Best Regards.
Reviewer 2 Report
The article is interesting but there are several lacks:
- Very extensive sections and poor English. You need to be more concise, much more. There are several repetitions throughout the manuscript and sentences are very long.
- Lack in standard deviations in some plots. Besides, the number of tables or figures is quite high. Is it possible to reduce it and move something to the SI?
- Several important topics and references are missing:
Baldelli, A., 2021. Evaluation of a low-cost multi-channel monitor for indoor air quality through a novel, low-cost, and reproducible platform. Measurement: Sensors, 17, p.100059.
Clements, A.L., Griswold, W.G., Rs, A., Johnston, J.E., Herting, M.M., Thorson, J., Collier-Oxandale, A. and Hannigan, M., 2017. Low-cost air quality monitoring tools: from research to practice (a workshop summary). Sensors, 17(11), p.2478.
Karagulian, F., Barbiere, M., Kotsev, A., Spinelle, L., Gerboles, M., Lagler, F., Redon, N., Crunaire, S. and Borowiak, A., 2019. Review of the performance of low-cost sensors for air quality monitoring. Atmosphere, 10(9), p.506.
Saini, J., Dutta, M. and Marques, G., 2020. A comprehensive review on indoor air quality monitoring systems for enhanced public health. Sustainable environment research, 30(1), pp.1-12.
Author Response
Dear Reviewer:
Manuscript ID: processes-2223824
Title: “An Empirical Analysis of the Aircraft Emissions by Operating from Scheduled Flights within the Domestic Market in Spain”
Thank you for your useful comments and suggestions on the language and certain parts of our manuscript. We have revised the manuscript to correspond to the reviewer's comments, and the revised manuscript has been submitted to the manuscript submission system of MDPI.
The authors really appreciate you for the constructive comments and suggestions to improve this paper.
Below are given our responses marked in red depending on each comment from your review.
We look forward to your positive response.
Very sincerely yours,
The Authors.
The article is interesting but there are several lacks:
- Very extensive sections and poor English. You need to be more concise, much more. There are several repetitions throughout the manuscript and sentences are very long.
Response: In reply to the comment above, the style of the manuscript has been revised following your comments. However, some parts have been extended a bit by adding a couple of paragraphs, as well as further plots and figures, according to suggestions given by other reviewers.
- Lack in standard deviations in some plots. Besides, the number of tables or figures is quite high. Is it possible to reduce it and move something to the SI?
Response: Thank you for pointing this out. Arithmetic averages and standard deviation have been added to maps showing partial emission per passenger and route in each case. Please see Figures 7-11 from version 3 of the manuscript.
- Several important topics and references are missing:
Baldelli, A., 2021. Evaluation of a low-cost multi-channel monitor for indoor air quality through a novel, low-cost, and reproducible platform. Measurement: Sensors, 17, p.100059.
Clements, A.L., Griswold, W.G., Rs, A., Johnston, J.E., Herting, M.M., Thorson, J., Collier-Oxandale, A. and Hannigan, M., 2017. Low-cost air quality monitoring tools: from research to practice (a workshop summary). Sensors, 17(11), p.2478.
Karagulian, F., Barbiere, M., Kotsev, A., Spinelle, L., Gerboles, M., Lagler, F., Redon, N., Crunaire, S. and Borowiak, A., 2019. Review of the performance of low-cost sensors for air quality monitoring. Atmosphere, 10(9), p.506.
Saini, J., Dutta, M. and Marques, G., 2020. A comprehensive review on indoor air quality monitoring systems for enhanced public health. Sustainable environment research, 30(1), pp.1-12.
Response: Thank you for such a valuable suggestion. In reply to the comment above, the four references have been added to the manuscript. Please see the part about future directions.
I hope all the efforts for the improvement of the manuscript according to your suggestion can meet the high expectations of the journal.
The Authors,
Best Regards.
Round 2
Reviewer 1 Report
The authors have improved the manuscript sufficiently. Well done.
Reviewer 2 Report
Great improvements! Your article can be published as it is.
