Overlooked Impacts of Urban Environments on the Air Quality in Naturally Ventilated Schools Amid the COVID-19 Pandemic

Round 1

Reviewer 1 Report

This study reported the impact of window open regimes on the indoor air quality of two school buildings with naturally ventilated condition located in Ljubljana, Slovenia. There were beneficial findings from the study for the communities especially who focus on urban climate and healthy buildings. The methodology was well designed and executed. However, there are several modifications required before final acceptance of this manuscript. Therefore. I recommend this manuscript for minor revisions.

The comments/suggestions that should be addressed are as follow:

1.      It is suggested to include a statement in section 5 with the findings briefly point by point and on how the present study may be useful in the future.

2.   I think Figures 6 and 7 should include the y-axis titles. The current figures seemed a little confusing for the readers to distinguish the plots.

 

3.      It is interesting to note in line 348 regarding the outdoor and relative humidity which were -4 to 2 degree C and around 85% respectively. On the other hand, figures 7 revealed that indoor temperature more than 17 degree C for both observed naturally ventilated classrooms. In this context, the wall insulation seems very good to reject the cold temperature as well as high relative humidity from the outdoor. The author should include the explanation of this condition in section 3. 

Author Response

Dear Editor,                                                                                             23 January 2023

 

I am pleased to submit our response to the comments on the original manuscript by Kristijan Lavtižar, Alenka Fikfak, Rok Fink, entitled Overlooked impacts of Urban Environments on the Air Quality in Naturally Ventilated Schools amid COVID-19 Pandemic, to be considered for publication in Sustainability (ISSN 2071-1050), special issue "Sustainability and Indoor Environmental Quality ".

The article has been modified regarding all 3 reviewers comments.

 

Please see the attachment and Kind Regards,

Kristijan Lavtižar

Corresponding Author

 

Author Response File: Author Response.pdf

Reviewer 2 Report

A brief summary

The research presented showed an exciting study on two primary schools and the ventilation of their classrooms, evaluating how each adapted to COVID-19 pandemic conditions and restrictions.

 

General concept comments

When you want to analyze the impact of the urban environment, it has to be set up the same ventilation regime for all classrooms. I'm not sure it was. Please comment.

I did not find the strict position of the sensor, which was cited in reference [5,35]. You wrote: "The gauges were placed at a minimum of 3 m away from the window and at least 1 m away from the nearest pupil [5,35]."

Measuring the distribution of pollutants and solid particles throughout the class at various points would be interesting.

Please explain the results in Tables 3 and 4. UC class had a higher ventilation rate (CO2 was lower), but the concentration of the PM2.5 and 10 was higher than for the UB class. You mentioned it in a discussion. Therefore, installing the outside measuring station in front of the evaluating classroom will be better.

 

Specific comments

In the introduction, you write about three urban environments: Urban Background, Urban Canyons and Urban Space. But only the two types are investigated. Is it explained somewhere in your work?

Citing literature is not numbered in ascending order.

Did occupants use the masks/respirators?

Please provide the information about the type of floor covering and walls.

Cited figures are numbered in the text incorrectly.

The formatting of Table 1 has to be improved.

In Figure 6 a and b, there are various ventilation regimes, but the label on the upper part of the graph is the same.

In Figures 6 and 7, you declare that it is a three-day measurement, but the x-axis starts at 7:50 and ends at 13:40.

Please specify better the frames/labels a- f in graphs. You used them in the text. It is not clear.

I do not recommend using the term data points. In my opinion, it is data sets. You did not measure at 34 data points/positions.

 

I recommend including references with Digital object identifiers (DOI).

Author Response

Dear Editor,                                                                                             23 January 2023

 

I am pleased to submit our response to the comments on the original manuscript by Kristijan Lavtižar, Alenka Fikfak, Rok Fink, entitled Overlooked impacts of Urban Environments on the Air Quality in Naturally Ventilated Schools amid COVID-19 Pandemic, to be considered for publication in Sustainability (ISSN 2071-1050), special issue "Sustainability and Indoor Environmental Quality ".

The article has been modified regarding all 3 reviewers comments.

 

Please see the attachment and Kind Regards,

Kristijan Lavtižar

Corresponding Author

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Minor revision is suggested.

 

Line 52: “The effectiveness these measures in schools were proven to be …” This sentence seems incorrect in grammar.

 

Line 182 and 183: I believe it should be “7:00 and 9:00” instead of “7.00 and 9.00”

 

Table 1: It’s suggested to rotate this table for readability.

 

Line 288: “The door was only opened during breaks, but most of the time the children stayed in their classroom, leaving only during sports education and following the last lesson.” What about the half-hourly occupancy during testing days? If there are situations that most children left the classroom for sport lesson, it should be noted. It’s suggested to add a plot to the Result Section to illustrate the occupancy rate throughout testing days.

 

 

Line 331: “The classroom has 6 groups of desks with space for 21 pupils, each sitting 1 m from another (Figure 4).” I believe it should be (Figure 5)

 

Line 340: “The average data for the three consecutive days at the two school locations UC and UB is shown in figure 5.” I think it should be “Figure 6”. There are some other mistakes like this one, please check.

 

Figure 6a: The textual description does not match the figure. For instance, “it can be seen that the PM2.5 show a rise in concentration, up to the point of the start of class, as the windows and doors are closed (b). The CO2 concentration increases by 1000 ppm during the same interval.” But in the figure, the marker “b” is at 10:00.

Also, “falling to just 35 μgm-3 at the 11:00 mark (e).” But marker “e” is at 12:50 in the figure.

I assume the markers like “a, b, c, d, e, f”, are misplaced. Please carefully check Figure 6a and 6b.

 

Line 388: ”The UV school”, I assume it should be “UC”.

 

Line 432-437: The authors claim that PM2.5 is a contributing factor to IAQ while outdoor temperature and humidity are not. But Table 2 shows all their p-value are less than 0,0001*.

 

Section 4.1: In the future work, I suggest to add some more experiments of control variables to find out the performance difference between variable ventilation manners, since current two cases differ in both school location and ventilation manner.

 

Line 513: “to two case t” ?

Author Response

Dear Editor,                                                                                             23 January 2023

 

I am pleased to submit our response to the comments on the original manuscript by Kristijan Lavtižar, Alenka Fikfak, Rok Fink, entitled Overlooked impacts of Urban Environments on the Air Quality in Naturally Ventilated Schools amid COVID-19 Pandemic, to be considered for publication in Sustainability (ISSN 2071-1050), special issue "Sustainability and Indoor Environmental Quality ".

The article has been modified regarding all 3 reviewers comments.

 

Please see the attachment and Kind Regards,

Kristijan Lavtižar

Corresponding Author

 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

I accept the article in its present form.