Review Reports

Round 1

Reviewer 1 Report

I found this paper interesting and worthy of publication. However, it needs significant restructuring and revision prior to publication. Please read through my comments given below, hopefully, they help you to improve the paper.

Introduction

I found your introduction unnecessarily long, without having a particular focus when organising the discussions. This section, in its current form, fails to substantiate the necessity of doing this research which is one of the very first purposes of having an introduction section. When reading this section, I felt that discussions are done without having any clear link in-between.

Having said all these, I would advise you to restructure the introduction section; first, talk about CO2 and its concomitant impacts on the built environment. Then, shift the discussion toward Saudi Arabia (SA) where your case study. In there, you need to illustrate the CO2 impacts connected to buildings’ operation/and construction. Upon that elaboration, briefly review some studies similar to yours, and demonstrate the contributions of your study to the current body of knowledge.

Please, be advised that the introduction section is expected not to be long, it needs to be short and precise. In the last paragraph, you need to portrait the contribution of your study for both SA and preferably for other nations/countries.

Research Methodology

First, you need to indicate that your research consists of how any phases, then you may start counting them. Also, I noticed so many grammatical and spellings errors throughout the entire text. Please, consider doing extensive proofreading prior to resubmission.

Please elaborate further on Data Collection and Data Processing. For instance, how exactly did the data cleansing carry out? What filters did you use? Did you use data clustering?

It was mentioned that the data collection was carried out for an entire month. Which month was it? Why that specific moth? How did you take into account the impact of climate on your data collection?

Also, I do not understand this sentence “The data was collected using two modes (a) Smart sensors that were 170 deployed in a single person and a joint office”. Did you install the sensors on only one person? What was his/her domain activity? Did he/she have the access to the entire building so that provides you with good coverage of data? Please elaborate in detail.

In addition, the locations are also unknown! Please, explain in detail why these locations are chosen! What the reasons behind selecting these locations. Please elaborate.

Results and Discussion
I can see that you have worked so hard for this research; however, the presentation could be better. For instance, Figure 8 is rather confusing for showing data collected in the morning and afternoon. This could be done separately, in two graphs via a comparative approach, comparing data collected in different locations. Plus, please add the unit for this pic as well.

It was endeavored to justify the high level of co2 concentrations. However, I do not see the discussion on the functions of these places. For instance, the praying area functions quite differently in terms of the operational hours compared to the office. Indeed, it has almost the same amount of co2 concentration as an office. Please, try to have some discussion on the impacts that the function of each location may have on co2.

I would like to also see what the SA’s standards say about the maximum acceptable level of CO2 in these spaces. Are there any standards in SA about this?

“In the final stage, a vulnerability map is generated based on carbon dioxide concentrations observed in the study as shown in Figure 14.” Why did you not give any explanation for this figure? What is the importance of this figure?

Author Response

Dear sir

Thanks for your constructive comments to make this paper better. We tried our best to address all of your comments in the best possible way we can. I hope that you will find it too in the paper. 

Thanks 

Shabir Hussain 

Author Response File: Author Response.pdf

Reviewer 2 Report

Title: Carbon Dioxide Footprint and Its Impacts: A Case of Academic Buildings Journal: Sustainability This study measures the level of CO2 at an academic building. The researchers have used a sensor-based automated system to find out the concentration of CO2 at different locations. This is an interesting study that is related to the scope of the journal. I suggest the following comments: 1- First and foremost, the introduction section is too lengthy. It is more like a project summary rather than a research article. Please summarize the introduction and keep the sections that are totally related to the subject. 2- Page 5, you said that the “later phase would review the works in the field of CO2 in the academic buildings”. However, you did not do that. I could not find a literature review section. Although you have mentioned some papers throughout the paper, you need to provide a cohort literature review and show the research gaps. 3- Talk a little more about the devices, equipment, and any machines you have used to collect data. 4- This observation is designed according to some assumptions. It would be best if you discussed the assumptions in detail. What type of assumptions (or conditions) did you apply? What would happen if you changed them? What are controllable? What are uncontrollable? … 5- I could not find any in-depth analysis or insights extracting from the results. The authors mostly reported the numbers and data from the sensors. This is not practical for decision-makers. You need to justify and discuss the results. Are there any specific reasons behind the results? 6- I am concerned about the generality of this study. Can we extend the result to other academic buildings? For example, building in other cities or other countries? As an instance, many academic buildings do not have prayer rooms? What would be the results? The factors such as air-conditioning systems, energy type, building age, number of employees, city population, surrounding areas, etc., will change the results. How do you use this study for other places? Provide a separate section and discuss this comment. 7- Discuss the limitations and challenges of the study in conclusion.

Author Response

Dear sir

Thanks for your constructive comments to make this paper better. We tried our best to address all of your comments in the best possible way we can. I hope that you will find it too in the paper. 

Thanks 

Shabir Hussain 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Greetings

The overall structure of the paper has improved now, though I still feel that there is much you can do to further enhance the quality of your paper. First, the quality of written English is low; thus, I ask for a major revision in this regard. Also, some comments are left unaddressed! for instance, in the research methodology section, you should start with an initial sentence, e.g., "the methodology of this research consists of X stages", then you can start counting your stages. Plus, I want you to further expand on your Recommendations and Suggestions section by discussing the limitations (e.g., assumptions) of your study (I see that you deleted this section). In this section, you may also have a discussion on the importance of embodied energy that has not been considered in your study (i.e., you can use this paper: Application of Life Cycle Energy Assessment in Residential Buildings: A Critical Review of Recent Trends - to develop your discussion). In this section, you may draw on the future direction of your study by highlighting the limitations of your research. 

Author Response

Dear Sir

Thanks for your kind, constructive comments to improve the paper. We tried our best to address our comments. I hope the current manuscript will meet your expectations. 

thanks 

Shabir

Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

I have no further comments for the authors.