Atmospheric Emissions in Ports Due to Maritime Traffic in Mexico

Round 1

Reviewer 1 Report

The authors made an effort and improved their paper. The subject is timely and relevant, and there is a need for studies like this. However, I have a few comments and suggestions given below.

1. Line 53 - "particles" are mentioned; maybe it would be better to use the wording "particulate matter - PM" or "particulates".
2. Please include the aim of the research in the Introduction section; it is not mentioned explicitly.
3. Are there any limitations of the study?

I hope that my comments and suggestions will be helpful.

Author Response

Dear Reviewer 1

We appreciate your invaluable time spent reviewing our study “Atmospheric emissions in ports due to maritime traffic in Mexico”. Each comment and suggestion were considered in this review stage (R1) for our manuscript which we wish to be published in JMSE. We are convinced that your suggestions will benefit our manuscript in accordance with the requirements of JMSE which is internationally recognized.

We answer each of your questions below. 

 

Comments and Suggestions for Authors

 The authors made an effort and improved their paper. The subject is timely and relevant, and there is a need for studies like this. However, I have a few comments and suggestions given below.

Response.

Thank you for your comment. According to the availability of our database used in this study, we have identified the temporal variability of atmospheric emissions due to the movement of ships for the Pacific and Gulf of Mexico from 2005 to 2020, including the International Maritime Organization implementations regarding the change in sulfur content in marine fuel. We found three key scenarios to consider the implementations of the International Maritime Organization which this allows a very important contribution in our country.

1. Line 53 - "particles" are mentioned; maybe it would be better to use the wording "particulate matter - PM" or "particulates".

Response.

Thanks for your observation and suggestion. For this new revision we have modified “particles” by “particulates” throughout the manuscript.

2. Please include the aim of the research in the Introduction section; it is not mentioned explicitly.

Response.

Thank you for your suggestion. We have modified the Introduction section indicating our contribution and objective for the development of the study. The changes made can be seen in this new review. However, we commented you that our main objective is to identify the level of atmospheric emission of the main pollutants that are emitted due to the movement of ships on the Pacific and Gulf of Mexico, since there is no detailed study on the subject. Environmental pollution due to the movement of ships in Mexico is not a national priority like other industrial sectors, therefore, our contribution in the development of this study is to strengthen Mexico’s national inventory regarding atmospheric emissions from the maritime sector.

3. Are there any limitations of the study?

Response.

Thank you for your question. A limitation for the development of our study was regarding the use of Automatic Identification System. In Mexico this information is confidential and in order to use it is necessary to have an agreement with the port and academic sectors, otherwise, the information is restricted. The use of the emission factors to identify the atmospheric emission level was another limitation. We have based ourselves on the emission factors published by the European Union and the United States because in Mexico emission factors have not yet been developed for the port sector. However, the official information from Mexico regarding the typology of vessels for the Pacific and Gulf of Mexico zone as well as the information available at the international level to estimate atmospheric emissions from port systems are a fundamental complement to identify the level of atmospheric emission.

Finally, we know the issue “environmental pollution in port systems” is not a priority activity in Mexico. The Mexican Institutes responsible to update the National Emission Inventories indicate in general context the situation of the level of atmospheric emissions from port systems, however it is necessary carried out more studies constantly because the port system activities in Mexico will continue to increase in the next few years. This study clearly reflects the situation of the trend atmospheric emissions from ships since 2005. These results contribute significantly according to International Maritime Organization and Marine Pollution agreements respect to reduce the atmospheric emissions by sulfur dioxide considering the change of fuel content in marine fuel.

Author Response File: Author Response.docx

Reviewer 2 Report

I don't have any new suggestions for the authors at the present time.

I show that they did some changes and it was enough to me.

Author Response

Dear Reviewer 2

We appreciate your invaluable time spent reviewing our study “Atmospheric emissions in ports due to maritime traffic in Mexico”. Thank you so much for your comments and suggestions to improve our job. We know that your suggestions were very important to integrate in our study. We hope our manuscript can be published in Journal of Marine Science and Engineering (JMSE).

We answer each of your questions below.

 

Comments and Suggestions for Authors

I don’t have any new suggestions for the authors at the present time.

I show that they did some changes, and it was enough to me.

Response.

We are pleased to inform you that your suggestions included in our manuscript that you so kindly told us, they were to improve our study and they comply with the Journal of Marine Science and Engineering standards. Thanks to your suggestions and comments, our manuscript had a greater integration and understanding in the Introduction, Method and Results sections.

Reviewer 3 Report

This study analyses ship emissions at port areas using a bottom-up approach. However, the study has several drawbacks. First of all, I cannot see strong methodological contributions against literature. Secondly, AIS data from Mexico is not used to conduct the detailed analysis of maneuvering, etc. These aspects hinder this paper significantly. Detailed major comments to address are:

1- The contributions of this work are not well discussed in the introduction. Contributions should be better clarified. If there is not any clear academic contribution against previous studies, this study cannot be published.

2- The specific research gap addressed by this work should be clarified in the introduction. Currently research gap is vague. Introduction should be enhanced.

3- AIS data analysis is not conducted in this work (or at least it is not clarified whether it was used). Normally, you should process AIS data to understand the percentage (and times) of maneuvering, anchoring, waiting, berthing, etc. If this is not done, this paper cannot be published.  

4- Components of emissions- canal passing, anchorage, etc come from strong assumptions from EU data, not mexico data.

5- Following papers all focus on emissions at ports. I encourage authors to cite all following and discuss in detail your contribution against them. Last two papers review studies on ship emissions in ports:

Greenhouse gas emissions from ships in ports–Case studies in four continents. Transportation Research Part D: Transport and Environment, 54, pp.212-224, 2017.

Atmospheric ship emissions in ports: A review. Correlation with data of ship traffic. Atmospheric Environment: X, 4, p.100050, 2019.

The multi-port berth allocation problem with speed optimization and emission considerations. Transportation Research Part D: Transport and Environment, 54, pp.142-159, 2017.

External costs from vessel emissions at port: a review of the methodological and empirical state of the art. Transport Reviews, 37(3), pp.383-402, 2017.

A review of energy efficiency in ports: Operational strategies, technologies and energy management systems. Renewable and Sustainable Energy Reviews, 112, pp.170-182, 2019.

6- There are papers for ships emissions from shipping and straights. You can cite and discuss following papers:

Big AIS data based spatial-temporal analyses of ship traffic in Singapore port waters. Transportation Research Part E: Logistics and Transportation Review, 129, pp.287-304, 2019.

Cold chain shipping mode choice with environmental and financial perspectives. Transportation Research Part D: Transport and Environment, 87, p.102537, 2020.

Minor:

1- In introduction paragraph 1, you can also note about newer regulations inlcuding ECAs, SECAs, etc. 

 

 

 

 

Author Response

Dear Reviewer 3

We appreciate your invaluable time spent reviewing our study “Atmospheric emissions in ports due to maritime traffic in Mexico”. His comments and suggestions have strengthened our manuscript which represents a fundamental advance for Mexico where there are no detailed studies regarding the level of atmospheric emission due to the movement of ships for Pacific and Gulf of Mexico. Based on his suggestions, we are convinced that our study will meet the Journal of Marine Science and Engineering (JMSE) requirements for possible publication. We have listened to your comments and suggestions in this review phase (R1) and then we respond to each of your questions and comments.

 

Comments and Suggestions for Authors

This study analyses ship emissions at port areas using a bottom-up approach. However, the study has several drawbacks. First of all, I cannot see strong methodological contributions against literature. Secondly, AIS data from Mexico is not used to conduct the detailed analysis of maneuvering, etc. These aspects hinder this paper significantly. Detailed major comments to address are:

Response.

We would like to tell you the following: Our study is based about the application of the information that exists at the international level because in Mexico it is not easy to access the specific information of the port sector, specifically the Automatic Identification System. The Bottom-Up method was selected to identify the atmospheric emission level for the main pollutants that are emitted to the atmosphere due to the movement of ships. The method relates the operation of the main and auxiliary engine in the maneuvering and hoteling stage as well as the emission factors established at the international level since in Mexico there is no development of emission factors for the port sector. Considering the implementations of the International Maritime Organization and that Mexico has ratified its participation in this Maritime Organization, this study represents a starting point for the development of other studies considering an important 15-year trend (2005 to 2020).

1- The contributions of this work are not well discussed in the introduction. Contributions should be better clarified. If there is not any clear academic contribution against previous studies, this study cannot be published.

Response.

Thank you for your comment and suggestion. We have modified the Introduction section integrating our contribution and objective for the development of this study. You can see this modification in this new revision phase. However, we comment you that the contribution of our study is to promote and strengthen the national emissions inventory in Mexico because there are no detailed studies regarding the level of atmospheric emissions from port systems. One of our objectives is that the results obtained from this study will be considered for the implementation or establishment applying air quality models to identify the concentration level that the population is exposed.

2- The specific research gap addressed by this work should be clarified in the introduction. Currently research gap is vague. Introduction should be enhanced.

Response.

Thank you for your comment. We agree with you, and we have responded to your request. We have modified the Introduction section. The focus of the Introduction for this new phase of review includes our contribution and why the development of this study is important. According to the institution responsible for updating and publishing the inventory of atmospheric emissions in Mexico, they still do not indicate in detail what is the level of atmospheric emissions from the main ports of Mexico for the Pacific and Gulf of Mexico. The level of atmospheric emission by type of ship is not indicated either. Given this consideration, this study reflects a starting point to identify the level of atmospheric emission from the main ports of Mexico and for the International Maritime Organization it represents a fundamental advance in the Marine Pollution Annex VI agreement because Mexico is a participant in this agreement.

3- AIS data analysis is not conducted in this work (or at least it is not clarified whether it was used). Normally, you should process AIS data to understand the percentage (and times) of maneuvering, anchoring, waiting, berthing, etc. If this is not done, this paper cannot be published.

Response.

Thank you for your comment regarding the Automatic Identification System (AIS). According to international studies about the Ship Traffic Emissions Assessment Model (STEAM) developed by Jalkanen and Johansson, the use of AIS is required to characterize the movement of ships in the cruise, maneuvering and hoteling stage, that is, the STEAM model works with the integration of AIS in real time to identify the level of atmospheric emission from ships using the algorithms developed by those authors. However, the STEAM model and the AIS are not the only tool for estimating atmospheric emissions in port. There are traditional methods to estimate atmospheric emissions, Top-Down and Bottom-Up method. We decided to use the Bottom-Up method because the type of ships arriving in Mexico is known. The technical information such as the power of the main and auxiliary engine, gross tonne level, emission factors, maneuvering and hoteling times were compiled from the European methodology because the company Lloyd's Register and Entec Corporation have carried out a lot of research regarding the details of the technical information of ships not only in Europe but also globally. In Mexico, the captaincy of at least 4 ports indicates the technical information of the ships which has a similarity with the publications of those companies, so we decided to use the data from Entec Corporation regarding the length of stay as well as the method to determine the power of the engines of ships that are located in the Pacific and Gulf of Mexico.

However, prior to the development of this study, we requested and sought the AIS in different port sectors of Mexico. We have not received a response so far. We are convinced that through the use of AIS regarding the position and speed of ships, cruising, maneuvering and docking times, the level of atmospheric emissions would be real, and the uncertainty factor associated with the measurement would be minimal. To access the AIS without restrictions, it is necessary to have an agreement between the port and academic sectors, otherwise, it is very difficult to access these databases in Mexico which represents a limitation for this study. We decided to include the use of AIS and the STEAM model in the Background section because they are currently considered as a system for estimating atmospheric emissions in port, otherwise, our background would be incomplete with respect to the current methodologies for estimating atmospheric emissions.

4- Components of emissions- canal passing, anchorage, etc come from strong assumptions from EU data, not Mexico data.

Response.

Thank you for your comment. Our answer is based on the previous comments. According to international studies, the Bottom-Up method represents the best scenario to identify the level of atmospheric emission in ports, which are based on the Entec Corporation methodology. The European Union studies not only consider the movement of vessels locally but have also developed studies globally considering a representative sample of vessels to determine the average length of stay based on the level of gross tonne by type of vessel. Also, United Nation Conference on Trend and Development (UNCTAD) has published in its annual reports the length of stay by type of ship and cargo. In Mexico, the information is required to be available regarding the details of the movement of vessels. There are no reduction speed zones, there are no emission control areas as in other countries. Therefore, our recommendations and future work include the use of AIS, considering this study as a first stage in the identification of the atmospheric emission level for the Pacific and Gulf of Mexico.

5- Following papers all focus on emissions at ports. I encourage authors to cite all following and discuss in detail your contribution against them. Last two papers review studies on ship emissions in ports:

Greenhouse gas emissions from ships in ports–Case studies in four continents. Transportation Research Part D: Transport and Environment, 54, pp.212-224, 2017.

Atmospheric ship emissions in ports: A review. Correlation with data of ship traffic. Atmospheric Environment: X, 4, p.100050, 2019.

The multi-port berth allocation problem with speed optimization and emission considerations. Transportation Research Part D: Transport and Environment, 54, pp.142-159, 2017.

External costs from vessel emissions at port: a review of the methodological and empirical state of the art. Transport Reviews, 37(3), pp.383-402, 2017.

A review of energy efficiency in ports: Operational strategies, technologies and energy management systems. Renewable and Sustainable Energy Reviews, 112, pp.170-182, 2019.

Response.

Thank you so much for your suggestion and to share the documents. We have integrated a discussion for these documents thought our manuscript. We identified the idea or paragraph to integrate these studies, and you can see it in the pdf version with highlights in yellow color. We know that the State of the Art for some studies are very important to consider in this study due to essentially integrate the situation of methods, analysis, updating the techniques to reduce the atmospheric emissions of criteria and greenhouse gases according to International Maritime Organization, Agreement of Paris, and Intergovernmental Panel on Climate Change. Thank you in advance.

6- There are papers for ships emissions from shipping and straights. You can cite and discuss following papers:

Big AIS data based spatial-temporal analyses of ship traffic in Singapore port waters. Transportation Research Part E: Logistics and Transportation Review, 129, pp.287-304, 2019.

Cold chain shipping mode choice with environmental and financial perspectives. Transportation Research Part D: Transport and Environment, 87, p.102537, 2020.

Response.

Thank you so much to share these studies. We have integrated these documents in our manuscript. The description for each you can see in pdf file with highlights in yellow color. Is relevant to consider other studies where describe the AIS to identify the problems in the maritime sectors. The principal goal to use the AIS is to characterize and to prevent accidents due to the movement of ships considering the spent time in maneuvering and hoteling phases. Also, some studies related to the movement of merchandise in Container or Bulk Dry is very important to reduce the atmospheric emissions in ports due to these ships are very studied in many cases due to the gross tonne level is higher than other ships. Moreover, the new technologies to reduce the atmospheric emissions integrate complex algorithms or statistical models to evaluate the relationship between the movement of ships and type of technology. Thank you in advance.

Minor:

1- In introduction paragraph 1, you can also note about newer regulations including ECAs, SECAs, etc.

Response.

Thank you for your comment and suggestion. In this new revision we have included the International Maritime Organization implementations corresponding to ECAs and SECAs in the Introduction section.

Finally, the issue of atmospheric emissions due to the movement of ships in port is not a priority in Mexico. However, it is necessary to carry out this type of study not only to identify the level of atmospheric emission but also to identify the level of concentration to which the population is exposed using these data (atmospheric emissions) to inputs in air quality modeling.

We know the limitations of our study; however, we know what to do in the future according to the methods available currently. We know of the need that exists in Mexico respect to the confidential information in the port sectors, of course, this is a limitation, but it is not the unique method to estimate atmospheric emission levels in a develop country as Mexico.

JMSE represents the best option to publish our study due to Marine Pollution Section considers aspects related to contribution of our study.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

My comments are addressed. I do not have more comments.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The article is very interesting. The introduction needs to be supported by bibliography for the study area. It would be useful to support your interesting and why you select this area by  references for Mexico. As far as it concerns  the methodology needs to be moderated. You mention the model  "STEAM". As i am not very familiar with this model, i think that it should be added an explanation about the model in the annex or as appendix. 

Comments for author File: Comments.pdf

Author Response

Dear Reviewer 1.

Thank you for your spent time in review our study, and we're gratefully for your comments and suggestions, we know that observations have strengthened our paper respect to the structure and visualization on Introduction, Method, Figures and Results.

Your comments and suggestions were considered into the paper. After to review your comments in the "peer-review-13967860v2.pdf", we comment you the tasks that we made,

1. We've modified the Figures including the titles on axis, units, and uncertainty in our results.
2. We integrated some references in the Introduction Section to enforce the area of study according to National Institutions in Mexico corresponding to Atmospheric Emission Inventory. Likewise, we included one paragraph to describe the area of study considering the movement of merchandise in Mexico for 2020.
3. We've explained those sentences that you consider insufficient in the Background Section.
4. Respect to the calculations or how we determine the atmospheric emissions by port in Pacific and Gulf-Caribbean, we prepared a supplementary file called "method" indicating our broadcast, database, emission factors, information by type of vessel. This supplementary file is an example on how to determine the atmospheric emissions by NO_x in maneuver and hoteling positions for Pacific and Gulf-Caribbean. The format of the supplementary file is on *.xls to identify the algorithm in the calculation sheet.
5. According to the English language and style into the paper, our co-worker is native of the United States from Wisconsin-Milwaukee. We comment you that the paper was corrected considering the style and spelling again. In the supplementary file called "english style" are the corrections made.

Point 1. You mention the model "STEAM". As i am not very familiar with this model, i think that it should be added an explanation about the model in the annex or as appendix.

Response 1. Respect to the Ship Traffic Emission Assessment Model (STEAM). We are convinced that this STEAM model is very important to use according to Automatic Identification System (AIS) to estimate the atmospheric emissions. There are three version of STEAM (STEAM, STEAM2 and STEAM3) and the characteristics are different, but the configuration is similar. These models have been developed by Jalkanen et al. (2009, 2012 and 2014) and Johansson et al. (2016) and they have compared the three version of STEAM. If we consider how STEAM works it's necessary to select the version of STEAM, what type of AIS is needed to evaluate, and other parameters. At this consideration, we believe it's necessary to spend more time for this task.

Finally, in the pdf file called "corrections to reviewer 1" you can see the corrections by us according to your suggestion and comments.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comment 1: In Section RESULTS AND DISCUSSION, The image quality of Fig. 5, 6, and 7 need to be increased.

Comment 2: In Equation 1, the given bottom-up method for estimating atmospheric emissions, does this method original? Please add the corresponding reference.

Comment 3: The contribution of this paper should be emphasized.

Author Response

Dear Reviewer 2.

Thank you for your spent time to review our paper. We understand that your comments have benefit the structure of our paper in the Method, Results, Figures and Contribution according to your comments. After having read your comments, we respond to each of your specific comments,

Point 1. In Section RESULTS AND DISCUSSION, The image quality of Fig. 5, 6, and 7 need to be increased.

Response 1. Thank you for your comment and suggestion. In fact, we modified the Figures according to the Guidelines for Authors respect to the resolution and quality to better visualization. Likewise, we include titles in the axis, and units to better interpretation.

Point 2. In Equation 1, the given bottom-up method for estimating atmospheric emissions, does this method original? Please add the corresponding reference.

Response 2. Thank you for your question and suggestion. The Equation 1 to determine the atmospheric emissions in ports from ships in maneuver and hoteling positions is considered as a traditional method. Trozzi and Vaccaro (2010), EMEP/EEA (2019), ENTEC (2019) they indicate in detail of this method. At this consideration, we based in that references to determine the level of atmospheric emission by port in Mexico. We've included the references in the Method Section.

Point 3. The contribution of this paper should be emphasized.

Response 3. Thank you for your comment. We're according with you. In the Introduction Section we have included some paragraphs and sentences related to the contribution of this study as well as we explained why develop this study for Mexico.

Respect to the English language and style. The paper was corrected again by our co-worker native in United States at Wisconsin Milwaukee. You can see the corrections of the English language and spelling in the file called "english style".

In the file called "manuscript corrected to reviewer 2" are located our corrections according to your comments, and in the supplementary file called "method" you can see our procedure to estimate atmospheric emissions in Mexican ports.

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper aims to estimate atmosphere pollution due to maritime traffic in Mexican ports. Atmosphere pollution due to shipping is an important topic, and there is a great need for papers like this. The authors made a great effort to collect and analyse emissions data, but the structure of the paper is not as it should be for publishing in JMSE. Only the Introduction section has a number; all other sections and subsections are without numbers. Some are typed with small and some with capital letters; please follow Instructions for Authors (https://www.mdpi.com/journal/jmse/instructions). Also, please pay attention to references; JMSE instructions are not followed. Please find extracts from Instructions to Authors regarding references: "References must be numbered in order of appearance in the text (including table captions and figure legends) and listed individually at the end of the manuscript." "In the text, reference numbers should be placed in square brackets [ ], and placed before the punctuation; for example [1], [1–3] or [1,3]. For embedded citations in the text with pagination, use both parentheses and brackets to indicate the reference number and page numbers; for example, [5] (p. 10). or [6] (pp. 101–105)." My other comments and suggestions are given below.

1. Lines 33-34 -  It is stated that the MARPOL Convention is adopted in 1973 to reduce atmosphere pollution; is this the only aim and goal of MARPOL?
2. Lines 54-55 - It is stated: "In 2018, ships spent an average of 23.5 hours in port (specifically, 2.05 days for bulk carriers and 0.7 days for container ships)."; there is no source for this statement; please include it.
3. Lines 61-63 - It is stated: "According to UNCTAD (2019), 64% of container port traffic occurs in Asia, followed by Europe (16%), North America (8%), Latin America and the Caribbean (7%), Africa (4%), and Oceania (2%)."; total percentage amounts 101%; please rectify.
4. Line 76 - Abbreviations PM, CO, NMVOC not written in full.
5. Line 77 - Abbreviation OMI used but not written in full.
6. Lines 107 - 109 - Please restructure the sentence: "Most of the vessels served in Pacific ports were of type Container and Bulk Dry, while types General and Tank were most frequent in Gulf-Caribbean ports."; types of ships included here are container ship, bulk carrier, general cargo ship and tanker. Please check throughout the paper.
7. In Table 1, "Roro cargo" is mentioned; I suggest using the abbreviation Ro-Ro or Ro/Ro (Roll on - Roll off).
8. Line 132 - Abbreviation "GT" is used but not written in full; please include.
9. Lines 145-147 - It is stated: "The model relies on information generated by in real time by the Automatic Identification System (AIS) (ship port). Message are sent every 5 minutes with updates on fuel consumption, changes in ship speed, changes in the power and load factor of the ME and AE, among other details."; is it true that fuel consumption, changes in power and a load factor of the ME and AE are transmitted over the AIS?
10. Line 275 - When writing equations, please follow Instructions for Authors.
11. Lines 325 - 339 - You were supposed to remove this part; please check the paper thoroughly before submitting it to the journal. It shows that you haven't read it completely before submitting it.
12. How were the emissions in Figure 4 obtained (estimated)?
13. Figures 4 and 5 - units are not given; please include. Below Figure 4, it is stated, "Units for CO2 are Gg/year."; what about others? Also, they should be included in the Figure.
14. Lines 445-446 - Same as under 11, please remove.
15. Lines 450-452 - It is stated as a recommendation: "Integrate the Automatic Identification System (AIS) for national ports in Mexico and
    use the bottom-up method to determine the atmospheric emission in the three phases of navigation (cruise, maneuver, and hoteling)."; could you please elaborate on this?
16. Recommendations and Future work subsections are composed of single sentences. Please expand each sentence and develop small paragraphs where each recommendation and proposal for future work will be elaborated on and explained.

I hope that my comments and suggestions will help to improve your paper.

 

Author Response

Dear reviewer 3.

Thank you very much for your spent time to review our manuscript. We're gratefully respect to suggestions and comments. Your observations have improved/strengthened our study throughout the manuscript. All your suggestions were considered into the manuscript to enforce the Introduction, Background, Method and Results.

Regarding the English language and style that you have suggested us, our native American co-worker from the University of Wisconsin Milwaukee has again reviewed the English language and style. The corrections of this new edition can be found in the attached file called "english style".

Likewise, we inform you that the supplementary file called "corrections to reviewer 3" shows our corrections made according to your suggestions and comments, and the supplementary file called "method" you can see our procedure to estimate the level of atmospheric emissions due to movement of ships in Mexico.

Below, we respond to each of your comments, questions, and suggestions that have strengthened our study.

Point 1. The paper aims to estimate atmosphere pollution due to maritime traffic in Mexican ports. Atmosphere pollution due to shipping is an important topic, and there is a great need for papers like this. The authors made a great effort to collect and analyze emissions data, but the structure of the paper is not as it should be for publishing in JMSE. Only the Introduction section has a number; all other sections and subsections are without numbers. Some are typed with small and some with capital letters; please follow Instructions for Authors (https://www.mdpi.com/journal/jmse/instructions). Also, please pay attention to references; JMSE instructions are not followed. Please find extracts from Instructions to Authors regarding references: "References must be numbered in order of appearance in the text (including table captions and figure legends) and listed individually at the end of the manuscript." "In the text, reference numbers should be placed in square brackets [ ], and placed before the punctuation; for example [1], [1–3] or [1,3]. For embedded citations in the text with pagination, use both parentheses and brackets to indicate the reference number and page numbers; for example, [5] (p. 10). or [6] (pp. 101–105)." My other comments and suggestions are given below.

Response 1. Thank you for your comments. We believe this study will be important in Mexico due to the structure and analysis of the data base to enforce the Atmospheric Emissions Inventories because, at the moment, there is no studies based in detail on information respect to determine the atmospheric emissions in ports. According to the format of the manuscript and considering the Guidelines for Authors in the first review the references can be "free format" (Chicago, APA, etc), however if the paper is accepted the references should be in JMSE format. Considering your suggestion, we've modified our references in JMSE format. Also, we've included the section numbers according to the JMSE format. When we submitted the manuscript to review some characters were modified (subscripts), we think it happened when the file was converted to PDF format, we sorry about that.

Point 2. Lines 33-34 - It is stated that the MARPOL Convention is adopted in 1973 to reduce atmosphere pollution; is this the only aim and goal of MARPOL?

Response 2. Thank you for your comment and question. The MARPOL does not consider only the atmospheric emissions into the environment (Annex VI). But it is the goal and focus of our study: Contribute to estimate the level of atmospheric emissions by ports in Mexico considering the movement of ships in Pacific and Gulf of Mexico. The main objective of MARPOL are prevent and minimize the effect into the marine environment considering to VI Annexes to it. These effects are related to accidental situations in the process of routine from ships.

Point 3. Lines 54-55 - It is stated: "In 2018, ships spent an average of 23.5 hours in port (specifically, 2.05 days for bulk carriers and 0.7 days for container ships)."; there is no source for this statement; please include it.

Response 3. Thank you for your comment. We've included the reference about it. In this case the reference corresponding to UNCTAD, 2019 or [2]

Point 4. Lines 61-63 - It is stated: "According to UNCTAD (2019), 64% of container port traffic occurs in Asia, followed by Europe (16%), North America (8%), Latin America and the Caribbean (7%), Africa (4%), and Oceania (2%)."; total percentage amounts 101%; please rectify.

Response 4. Thank you for your comment. It is an important observation. We've reviewed the UNCTAD,2019 reference, and we found these values (%). We don't know which % is incorrect. Maybe, the rounding to the next figure causes this error.

Point 5. Line 76 - Abbreviations PM, CO, NMVOC not written in full.

Response 5. Thank you for your suggestion. In this case in the Abstract Section are located those abbreviations in full.

Point 6. Line 77 - Abbreviation OMI used but not written in full.

Response 6. Thank you for this observation. Abbreviation OMI was deleted throughout the document, the correct abbreviation is IMO.

Point 7. Lines 107 - 109 - Please restructure the sentence: "Most of the vessels served in Pacific ports were of type Container and Bulk Dry, while types General and Tank were most frequent in Gulf-Caribbean ports."; types of ships included here are container ship, bulk carrier, general cargo ship and tanker. Please check throughout the paper.

Response 7. Thank you for your observation. We've modified this error throughout the document. We've characterized four types of ships: RoRo, Container, Bulk Dry and Tank.

Point 8. In Table 1, "Roro cargo" is mentioned; I suggest using the abbreviation Ro-Ro or Ro/Ro (Roll on - Roll off).

Response 8. Thank you for your suggestion. We're according with you. We've changed RoRo Cargo by RoRo.

Point 9. Line 132 - Abbreviation "GT" is used but not written in full; please include.

Response 9. Thank you for your suggestion. The abbreviation GT correspond to Gross Tonne, we've modified this abbreviation throughout the paper.

Point 10. Lines 145-147 - It is stated: "The model relies on information generated by in real time by the Automatic Identification System (AIS) (ship port). Message are sent every 5 minutes with updates on fuel consumption, changes in ship speed, changes in the power and load factor of the ME and AE, among other details."; is it true that fuel consumption, changes in power and a load factor of the ME and AE are transmitted over the AIS?

Response 10. Thank you for your comment and question. According to studies an international level using the AIS (by IMO), more in specific Jalkanen et al. (2009, 2012, 2014), and Johansson et al. (2016), AIS can provide a database corresponding with the information of type of ship in specific the speed and location, however, the authors have developed algorithms to estimate the fuel consumption, load factor for the main engine and auxiliary engine, emission factors, power of main and auxiliar engines considering the AIS by minute or five minutes. Also, they indicate that the estimation of atmospheric emissions using the AIS the uncertainty is minimal, and the results are more realistic.

Point 11. Line 275 - When writing equations, please follow Instructions for Authors.

Response 11. Thank you for your comment. We've taken it into account.

Point 12. Lines 325 - 339 - You were supposed to remove this part; please check the paper thoroughly before submitting it to the journal. It shows that you haven't read it completely before submitting it.

Response 12. Thank you for your notification. In this case the Reviewer 1 made those comments in these lines because we reviewed his file to us, and we found those comments by him. We don't know what happened. We sorry about it.

Point 13. How were the emissions in Figure 4 obtained (estimated)?

Response 13. Thank you for your question. Our broadcast was based to estimate the atmospheric emissions in port during the maneuver and hoteling positions due to movement of ships, according to Equation 1. Then, it let us separate the atmospheric emissions from maneuvering and hoteling positions considering topology of ships. We create a supplementary file called "method" where anyone can see our algorithm to estimate atmospheric emissions on annual base.

Point 14. Figures 4 and 5 - units are not given; please include. Below Figure 4, it is stated, "Units for CO2 are Gg/year."; what about others? Also, they should be included in the Figure.

Response 14. Thank you for your suggestion. We've modified all Figures to better interpretation. We've included the titles on axis and units. The reviewer 1 considered too the same adjustment in the Figures.

Point 15. Lines 445-446 - Same as under 11, please remove.

Response 15. Thank you for your observation. Same as under 12. We sorry about it.

Point 16. Lines 450-452 - It is stated as a recommendation: "Integrate the Automatic Identification System (AIS) for national ports in Mexico and
use the bottom-up method to determine the atmospheric emission in the three phases of navigation (cruise, maneuver, and hoteling)."; could you please elaborate on this?

Response 16. Thank you for your comment and question. In fact, we use the bottom-up method in this study to estimate the atmospheric emission in Mexico. However, it's necessary to integrate the Automatic Identification System (AIS) a national level in Mexico due to the movement of ships and estimate the atmospheric emissions from AIS and compare the results of this study in the maneuver and hoteling position because cruising phase doesn't estimate in this study due to the information AIS is confidential as well as the anchoring phase.

Point 17. Recommendations and Future work subsections are composed of single sentences. Please expand each sentence and develop small paragraphs where each recommendation and proposal for future work will be elaborated on and explained.

Response 17. Thank you for your comments and suggestions and we're according with you. We've modified the sentences explaining its importance considering the results of this study.

All corrections you can see in the file called "manuscript corrected to reviewer 3".

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comment1:

In this approach, the aggregation of the emissions produced by all the ships estimates the total emissions. 
The emissions are then geographically defined based on assumptions, for example, ship activities or single geographic cells. 

• How did the information about the maritime traffic in the port section obtain?  
• Does the author use Automatic Identification System (AIS) data to refine the dataset?
• Will the data resource influence the conclusion of the paper?

Reviewer 3 Report

The authors made a great effort to improve the paper. However, I still have few points that need to be changed before considering the paper for publishing.

1. Please replace the wording "tank ship" with "tanker ship" or only "tanker" throughout the paper.
2. Instead of the wording "bulk dry", use "dry bulk" if you are referring to cargo; if you are referring to ship type, please use the wording "bulk carrier" throughout the paper.
3. In the revised version of the paper, lines 289-290, it is stated: "Message are sent every 5 minutes with updates on fuel consumption, changes in ship speed, changes in the power and load factor  of the ME and AE, among other details." I have read the papers that you have referenced for this statement. I have not found a statement that AIS is transmitting data regarding ME and AE consumption and others; it is used only for "identification and the determination of the location and instantaneous speeds of the vessels". Then, based on the obtained data, emissions are estimated. Please, be aware that AIS is connected to the GPS from where it obtains the ship's speed and positions, which are then transmitted to other ships. Also, the AIS status (moored, anchored, underway) is being updated manually by the officers, so that part might be inaccurate. However, data regarding engine consumption, load and others are not being transmitted to my best knowledge. Please change this sentence.

I hope that my comments and suggestions will be helpful.