Review Reports - Measurement of Road Transport Emissions, Case Study: Centinela-La Rumorosa Road, Baja California, México

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study is processed according to the HDM-4 methodology, but I consider it necessary to draw attention to a few formal comments.

· The introduction and chapter 2 are quite extensive to the detriment of the method and assessment

· - The study uses the term "particulate matter" abbreviated PM or "particulates" Par (PAR); it would be appropriate to explain or unify the terms;

· - Similarly, "average annual daily traffic" is denoted by the abbreviation AADT and also TDPA, it would be appropriate to unify

· - Chap. 2.1 creation of pollutant emissions, in the description of emissions produced by transport, there is no description of HC and Pb, these pollutants are also produced by transport and evaluated in the study

· - Chap. 3 – the description of the methodology lists 4 SWs for calculating emissions from road transport, but then only SW HDM-4 is used in the study. It is not stated from which SW the emission factors used come from

· - Chap. 3.1 input data states that the calibrations of vehicle speed data were verified by a highway speed study according to the methodology described in [86]. However, the cited literature is in Spanish, so the methodology should be briefly described

· - Chap. 3.2 – it is stated that the calibration factors from the HDM-4 program have been redefined, but which Ke0 or Ke1?

· - The study works with level 1 calibration – theoretical data (databases, studies) and level 2 – direct measurements of local conditions, including air quality monitoring; however, these data are not presented in the thesis;

· - Chap. 3.2 - incorrect numbering of formulas, equation (3) is omitted;

· - Formulas for determining NOx are also not given; in the literature [1], (3) is the equation for NOx;

· - It would be appropriate to include fundamental citations referring to the methodology and calculations with literature in the English language;

· - Equation (9) ..."software results" which SW? For example Outputs of SW HDM-4 are also for 1000 vehicle km (vehkm)

· - For equations (8), (9) and (10) no units are given;

· - What is the difference between equation (8) and (10)?

· - What is meant by the term "emissions per vehicle"?

· - Note to equation (10): total road traffic emissions TEOC should be the sum of groups of classified vehicles; but equation (10) represents emissions from only one group of vehicles;

· - Tab. 1,3,4,5 indicate vehicle types, equation (10) indicates CLV - vehicle classification: do they mean the same thing?

· - It would be appropriate to mark the tables with the same abbreviations as the inputs to the equations;

After incorporating the comments, I recommend accepting.

Author Response

The study is processed according to the HDM-4 methodology, but I consider it necessary to draw attention to a few formal comments.

The introduction and chapter 2 are quite extensive to the detriment of the method and assessment

Response:

We appreciate your comments, in this new version of the manuscript adjustments were made in these sections to address your recommendations and those of the other reviewers.·

- The study uses the term "particulate matter" abbreviated PM or "particulates" Par (PAR); it would be appropriate to explain or unify the terms;

Response:

Based on his recommendation, the term was unified as particulate matter (PM)

- Similarly, "average annual daily traffic" is denoted by the abbreviation AADT and also TDPA, it would be appropriate to unify

Response:

the term was unified as average annual daily traffic (AADT)

- Chap. 2.1 creation of pollutant emissions, in the description of emissions produced by transport, there is no description of HC and Pb, these pollutants are also produced by transport and evaluated in the study

Response:

A description of HC and Pb emissions is added in this version of the manuscript.

- Chap. 3 – the description of the methodology lists 4 SWs for calculating emissions from road transport, but then only SW HDM-4 is used in the study. It is not stated from which SW the emission factors used come from

Response:

The software described was tested before the beginning of the research to assess its application with the case study and the available data. In this new version, this clarification is made

- Chap. 3.1 input data states that the calibrations of vehicle speed data were verified by a highway speed study according to the methodology described in [86]. However, the cited literature is in Spanish, so the methodology should be briefly described

Response

By your recommendation, a clearer description was added about the methodology for calculating the point speed

- Chap. 3.2 – it is stated that the calibration factors from the HDM-4 program have been redefined, but which Ke0 or Ke1?

Response

In all the HDM-4 emission models, there are two calibration factors, K0 and K1. K0 may be interpreted as a rotational calibration factor for a given exhaust emission. For this study k0 was the calibration calibrated for this research. K1 factor calibration It involves field studies with direct measurement of the various characteristics of the vehicles since this factor is closely linked to the IFC (Instant Fuel Consumption). for future research desirable to perform these measurements.

By your recommendation, this is clarified in chapter 3.2 of the new version of the manuscript. Also in discussion it is clarified the absence of calibration of the factor k1

- The study works with level 1 calibration – theoretical data (databases, studies) and level 2 – direct measurements of local conditions, including air quality monitoring; however, these data are not presented in the thesis;

Response:

More information was added about the data used, the databases and clearer explanations of the methods. Specific data is not included in detail in order to avoid confusion and make the method replicable. For example, the equations establish the predefined calibration factors, but it clearly explain how to perform said calibration.

- Chap. 3.2 - incorrect numbering of formulas, equation (3) is omitted;

Response

This was caused by a formatting error. Corrected, we appreciate your observation.

- Formulas for determining NOx are also not given; in the literature [1], (3) is the equation for NOx;

Response:

This was caused by a formatting error. Corrected

- It would be appropriate to include fundamental citations referring to the methodology and calculations with literature in the English language;

Response:

Chapter 3 was modified for a better understanding of the methods used as well as the sources of information so that the procedure can be replicated.

- Equation (9) ..."software results" which SW? For example Outputs of SW HDM-4 are also for 1000 vehicle km (vehkm)

Response: It was clarified that the results obtained by HMD-4 were used

- For equations (8), (9) and (10) no units are given;

Corrected

- What is the difference between equation (8) and (10)?

Response: Equation 10 was used to define the emissions in each section of the road

- What is meant by the term "emissions per vehicle"?

Response:

It consists of a general estimate of the emissions generated by each vehicle considered in the AADT. This allows us to understand the behavior of the different variables and their effect on the reduction or increase of emissions.

- Note to equation (10): total road traffic emissions TEOC should be the sum of groups of classified vehicles; but equation (10) represents emissions from only one group of vehicles;

Response:

This equation informs the calculation for each vehicle. The results of these are added to obtain the total emissions of each section considering all the vehicles.

- Tab. 1,3,4,5 indicate vehicle types, equation (10) indicates CLV - vehicle classification: do they mean the same thing?

Response: Corrected , is the new term VCL

- It would be appropriate to mark the tables with the same abbreviations as the inputs to the equations;

Corrected.

After incorporating the comments, I recommend accepting.

Reviewer 2 Report

Comments and Suggestions for Authors

The paper uses the HDM-4 calculation tool to quantitatively estimate the emissions generated from road operations.

In recent years, research topics related to environmental justice have timely been desired to improve air pollution in developing countries and areas of poverty, as well as air pollution in developed countries. This study presents the need to implement strategies to reduce emissions and environmental impacts generated by vehicle operations on roads in developing countries.

The sentence structure is clear.

However, some sentences and words are not clear to the reader. We recommend that the manuscript be accepted for publication in Applied Sciences with all the points raised by the reviewers corrected or a rational explanation added to the paper.

Specific Comments

P1 Abstract:

A single paragraph of about 200 words maximum.

Papers that do not strictly adhere to the rules outlined in the Instructions for Authors will not be accepted for publication.

Words such as "Par" and "PB" may be used to describe model commands, but are not appropriate in a paper.

All "2 "s in CO2 and SO2 should be subscripted.

In equation (6) on p. 17, the word "Particulate Matter (PM)" is listed as "Par" in the text instead of "Particulate Matter (PM)," which is inconsistent.

A paper that contains sentences and words that are not carefully written is not worth the reader's time, or leads to the misconception that the data presented by the authors are not as carefully written as the sentences and words, which is an act that lacks the credibility and dignity of all the authors.

The reviewer specializes in environmental chemistry but is not an expert in emissions estimation models, and therefore cannot address the credibility of the data.

P2 L77:

carbon dioxide (CO2)

The first time the word CO2 appears, it should be abbreviated to "carbon dioxide (CO2)" in P2 L54.

When it appears for the second and subsequent times, it is generally abbreviated as CO2.

The phrase "carbon dioxide (CO2)" appears 12 times, hydrocarbons (HC) 7 times, carbon monoxide (CO) 8 times, nitrogen oxides (NOx) 4 times, sulfur oxides (SO2) 3 times.

At this point, normal reviewers think that the manner in which the text is read by others is inappropriate.

We are about to reject the journal and urge resubmission after careful revision.

P3L100:

Despite the fact that the word "carbon dioxide (CO2)" appears 12 times, there is no explanation for the first appearance of PM10.

An explanation such as PM10 (particulate matter 10 micrometers or less in diameter) should be added.

P3 L131-L145

This text is inappropriate to be included in "1. Introduction" because it describes the experimental method.

P3 L131-L145 should be deleted because a similar description is provided on P14-15.

Author Response

The paper uses the HDM-4 calculation tool to quantitatively estimate the emissions generated from road operations.

The sentence structure is clear.

Response: An extensive review of the phrases and words of the manuscript was carried out, additionally the errors framed by the reviewers were addressed.

Specific Comments

P1 Abstract:

A single paragraph of about 200 words maximum.

Corrected

Papers that do not strictly adhere to the rules outlined in the Instructions for Authors will not be accepted for publication.

Words such as "Par" and "PB" may be used to describe model commands, but are not appropriate in a paper.

Response:

Based on your recommendation, the term was unified as particulate matter (PM)

All "2 "s in CO2 and SO2 should be subscripted.

Corrected

In equation (6) on p. 17, the word "Particulate Matter (PM)" is listed as "Par" in the text instead of "Particulate Matter (PM)," which is inconsistent.

Response:

Based on your recommendation, the term was unified as particulate matter (PM)

Response

We appreciate your comments. An extensive review of the phrases and words of the manuscript was carried out, additionally the errors framed by the reviewers were addressed.

The reviewer specializes in environmental chemistry but is not an expert in emissions estimation models, and therefore cannot address the credibility of the data.

P2 L77:

carbon dioxide (CO2)

Corrected

The first time the word CO2 appears, it should be abbreviated to "carbon dioxide (CO2)" in P2 L54.

When it appears for the second and subsequent times, it is generally abbreviated as CO2.

Corrected throughout the text

The phrase "carbon dioxide (CO2)" appears 12 times, hydrocarbons (HC) 7 times, carbon monoxide (CO) 8 times, nitrogen oxides (NOx) 4 times, sulfur oxides (SO2) 3 times.

Corrected throughout the text

At this point, normal reviewers think that the manner in which the text is read by others is inappropriate.

An extensive review was carried out to resolve this issue

We are about to reject the journal and urge resubmission after careful revision.

P3L100:

Despite the fact that the word "carbon dioxide (CO2)" appears 12 times, there is no explanation for the first appearance of PM10.

Corrected

An explanation such as PM10 (particulate matter 10 micrometers or less in diameter) should be added.

Added

P3 L131-L145

This text is inappropriate to be included in "1. Introduction" because it describes the experimental method.

P3 L131-L145 should be deleted because a similar description is provided on P14-15.

Response:

The cited text mentions the objective of the article, it does not describe the research methodology as such.

We appreciate your comments on this new version of the manuscript, an extensive review of the phrases and words of the manuscript was carried out, additionally, the errors framed by the reviewers were addressed. Also, a clearer description was added about the methodology for calculating the point speed, and some descriptions missing of emissions were added. Finally, more information was added about the data used, the databases, and clearer explanations of the methods.

Reviewer 3 Report

Comments and Suggestions for Authors

Summary

The authors of the manuscript present a current topic in the field of research on anthropogenic emissions in connection with road transport, using the example of a case study from a selected part of the transport infrastructure in Mexico.

I see the main goal of the manuscript as an effort for further, scientifically justified, expansion of knowledge and support for the creation of data databases on the issue.

The main contribution and strength of the manuscript is the research contribution that provides a presented approach to the quantification of pollutant emissions specifically along road sections in Baja California, Mexico. The study has its limitations, expressed in Section 4.

General concept comments

The submitted manuscript is presented in a well-structured manner. The content of the case study is clear and relevant to the issue of investigating emissions due to the operation of cars in road transport.

99 cited references are also relevant to the research issue.

The manuscript is scientifically based with an experimentally validated fieldwork design suitable for data collection, identification, analysis, and evaluation.

The methodological approach for the quantification of pollutants from road traffic, presented in section 3, and the results of the case study are reproducible based on the details provided in the manuscript for other users, respectively. researchers.

This manuscript is based on the study of extensive literature at home and abroad, which made it possible to assimilate and apply knowledge within the fieldwork of the authors. In addition, the authors used primary data from before the Covid-19 pandemic. Data are interpreted throughout the manuscript in a reasonable and comprehensible manner. The authors used the emission models of the SW tool HDM-4. The experimental results in the manuscript show that there will be 372.5 tons of pollutant emissions generated by road traffic in the investigated highway section. The case study could have included a broader description of the use of the acquired knowledge for public policymakers and further scientific work to strengthen the scientific databases on the topic.

The results are supported by 5 figures and 8 tables that are practical and present relevant data.

The authors also used knowledge from a rich reference base and the current state of the art in solving the problem.

In my opinion, the partial conclusions of the solution to the problem follow the presented evidence and arguments. I found no ethical misconduct.

Specific comments

Minor revisions:

To improve the manuscript for the reader, I recommend:

In the Introduction section, formulate the research questions of the case study to which researchers are looking for answers, or hypotheses that will be verified.

In the Conclusions section, the authors evaluate the fulfillment of the main objective of the manuscript and the answers to the research questions.

Remove duplication in table markup:

In line 584:

Table 6. Point speed study results.

In line 740:

Table 6. Pollutant emissions generated by the operation in the case study.

Author Response

99 cited references are also relevant to the research issue.

The manuscript is scientifically based with an experimentally validated fieldwork design suitable for data collection, identification, analysis, and evaluation.

The results are supported by 5 figures and 8 tables that are practical and present relevant data.

The authors also used knowledge from a rich reference base and the current state of the art in solving the problem.

In my opinion, the partial conclusions of the solution to the problem follow the presented evidence and arguments. I found no ethical misconduct.

Specific comments

Minor revisions:

To improve the manuscript for the reader, I recommend:

In the Introduction section, formulate the research questions of the case study to which researchers are looking for answers, or hypotheses that will be verified.

Response:

We appreciate your comments, in this new version of the manuscript adjustments were made in these section to address your recommendations and those of the other reviewers.·

In the Conclusions section, the authors evaluate the fulfillment of the main objective of the manuscript and the answers to the research questions.

Remove duplication in table markup:

Corrected

In line 584:

Table 6. Point speed study results.

This was caused by a formatting error. Corrected

In line 740:

Table 6. Pollutant emissions generated by the operation in the case study.

This was caused by a formatting error. Corrected