Influence of the Heating System on the Indoor Environmental Quality—Case Study
Round 1
Reviewer 1 Report
Dear Author(s),
Your article is interesting and can meet the requirements of scientific article. The overall quality of the paper however is below average, especially the figure quality and some aspects are not clear. Bellow you can find my remarks:
1. Minor English mistakes in the text, please proofread before submitting again
2. ALL figures need to be better quality, especially the ones showing the results like fig 7,8,9.
3. Explain in the introduction what IEQ means in lie 29 were it is mentioned first not line 39
a. You refer to “indoor environment” as “IEQ” (both in line 39 and then in 62) – shouldn’t it be just “IE” or change the explanation to “indoor environment quality”? It must be consistent.
b. Please explain what is the difference between IAQ and IEQ- as specialist in the field we know but it is important to explain in the introduction for others and why you use the IEQ.
4. Same comment for NZEB
5. Line 57: what do you mean by: The same was achieved 100% due to the COVID-19 pandemic [17].? That instead of 90% of out time indoors we now spend 100%? This is unclear the way you have phrased it
6. When you write a phrase like: “According to a study” please add the author e.g.: “According to a study by author et al. [1]”
7. In the introduction, please cite the importance of contaminant inleak studies as they will influence the air quality and environment, such work like:
Scislo L “ Air leakage modelling and its influence on the air quality inside a garage” E3S Web of Conferences, Volume 443 July 2018, DOI: 10.1051/e3sconf/20184400172
And: Szczepanik N. “Comparison of cfd and multizone modeling from contaminant migration from a household gas furnace” Atmosphere, Volume 12, Issue 17 January 2021, DOI: 10.3390/ATMOS12010079
8. In the methods section why did you choose the hight of the measurement at 0.75m?
9. Is there any reason why you chose the test building for this study? Was it particularly venerable to contaminants or bad environmental conditions?
10. If possible, in figure 3 – turn off the mesh behind the floor plan (it makes it unclear) and either explain what the yellow arrow is or delete it
11. In the methods section – add what uncertainty of the measuring tools you have, later in the results (line 2015) you have e.g. 5.6% difference in the measured temperatures, or the change between 22.33 °C to 23.51°C – could this be just an error of the instrumentation? It is a very small difference.
Please add the measurement uncertainties
12. Why are you discussing the construction in point 2.4? will it influence the IAQ? If it might influence the VOC then please say so.
13. In general, you describe the building in a lot of detail and less about the measurements themselves or the equipment and the ventilation system. It would be better to show the building and say that the room taken into consideration is on X floor facing the direction of (e.g. north) and next to the kitchen. If the structure of rest of the floorplan (such as the fitness room) do not influence your study, then do not mention them in the paper.
14. You have no description of the ventilation system – is it a system with 100% fresh air or is the air recuperated? What is the fresh air flow? How is this compared to the maximum occupancy you observed? Was there a control system that regulated the amount of air that flowed or was it constant? All this is important for your study as you could have had a situation were there where only 5 people in the room and the flow rate of 300 m3/h which would be double the needed about.
15. Figure 5 is unclear – either make it more visible or delete it. It cannot be this way – if the boiler room is not part of your study (not in the room you made measurements) then I would suggest deleting the picture as it is not relevant to the study. It would be better to add some information about how the system works in the monitored meeting room.
16. Line 199: what does “under similar conditions” mean? – this is important as all the measured parameters depend on the occupancy schedule. Did you know how many people where in the meeting room during each week? Could it be that one heating system was better because there was less occupants during that period? This is crucial to the study.
17. Line 212: instead of “Figure (Fig. 7)” just put “Figure 7 shows”.
18. In line 302: In conclusion, it can be stated that both systems meet the requirements set by the Decree of the Ministry of Health of the Slovak Republic, but it is not clear from the obtained results which of the systems ensures a better quality of the indoor environment. – you will not be able to see which system is better if you did not study the occupant schedules.
19. You say a lot about the IAQ and IEQ in the beginning of the article but then do not refer to them in the discussion or conclusions.
Comments for author File: 
Comments.pdf
Author Response
Response to reviewer 1
We are thankful to the reviewer for your insightful comments which helped in improving the clarity of the work. We have revised the paper thoroughly according to your comments.
Reviewers' Comments:
- Minor English mistakes in the text, please proofread before submitting again.
Response. The manuscript was proofread and mistakes were fixed.
- ALL figuresneed to be better quality, especially the ones showing the results like fig 7,8,9.
Response: All figures are changed by ones with better quality.
- Explain in the introduction what IEQ means in lie 29 were it is mentioned first not line 39
- You refer to “indoor environment” as “IEQ” (both in line 39 and then in 62) – shouldn’t it be just “IE” or change the explanation to “indoor environment quality”? It must be consistent.
- Please explain what is the difference between IAQ and IEQ- as specialist in the field we know but it is important to explain in the introduction for others and why you use the IEQ.
Response: Introduction is updated with respect to understand the difference between IEQ and IAQ. We tried to improve the introduction so as not to mix the terms of the indoor environment with the indoor environmental quality.
- Same comment for NZEB
Response: corrected
- Line 57: what do you mean by: The same was achieved 100% due to the COVID-19 pandemic [17].? That instead of 90% of out time indoors we now spend 100%? This is unclear the way you have phrased it
Response: Thank you very much for note. We changed the sentences to clarify the meaning of the text.
- When you write a phrase like: “According to a study” please add the author e.g.: “According to a study by author et al. [1]”
Response. Fixed according to the recommendation. Thank you.
- In the introduction, please cite the importance of contaminant inleak studies as they will influence the air quality and environment, such work like:
Szczepanik-Ścisło, N.; Ścisło, L. Air leakage modelling and its influence on the air quality inside a garage. E3S Web of Conferences, Volume 443 July 2018, DOI: 10.1051/e3sconf/20184400172
Szczepanik-Ścisło, N.; Ścisło, L. Comparison of cfd and multizone modeling from contaminant migration from a household gas furnace. Atmosphere, 12(17), 2021, 1-11, DOI: 10.3390/ATMOS12010079
Response: The references are added. Thank you for linking to interesting publications.
- In the methods section why did you choose the hight of the measurement at 0.75m?
Response: The measuring instruments were placed on the table in the meeting room. The high of the table is 0.75 m and this high represents breathing zone of the sitting person.
- Is there any reason why you chose the test building for this study? Was it particularly venerable to contaminants or bad environmental conditions?
Response: The building for monitoring was chosen due to two methods of heating, the first method is heating using a ceiling radiant system and the second with a fan-coil. The main goal was to compare the difference in IEQ using these two systems of the heating. The first measurement (first week) was performed with heating using a ceiling radiant system, the second measurement (second week) with heating with a fan-coil.
- If possible, in figure 3 – turn off the mesh behind the floor plan (it makes it unclear) and either explain what the yellow arrow is or delete it
Response: Figure 3 is removed because the monitoring was performed only on the second floor.
- In the methods section – add what uncertainty of the measuring tools you have, later in the results (line 2015) you have e.g. 5.6% difference in the measured temperatures, or the change between 22.33 °C to 23.51°C – could this be just an error of the instrumentation? It is a very small difference.
Please add the measurement uncertainties
Response: Thank you for your valuable comment. We added the Table 1 with the characteristics of the measuring instruments, with the accuracy and resolution.
- Why are you discussing the construction in point 2.4? will it influence the IAQ? If it might influence the VOC then please say so.
Response: We added sentence: “Below are described the built-in building materials and HVAC systems that can have an impact on IEQ of the investigated building.”
- In general, you describe the building in a lot of detail and less about the measurements themselves or the equipment and the ventilation system. It would be better to show the building and say that the room taken into consideration is on X floor facing the direction of (e.g. north) and next to the kitchen. If the structure of rest of the floorplan (such as the fitness room) do not influence your study, then do not mention them in the paper.
Response: We corrected the section about the floor description. Irrelevant information has been removed.
- You have no description of the ventilation system – is it a system with 100% fresh air or is the air recuperated? What is the fresh air flow? How is this compared to the maximum occupancy you observed? Was there a control system that regulated the amount of air that flowed or was it constant? All this is important for your study as you could have had a situation were there where only 5 people in the room and the flow rate of 300 m3/h which would be double the needed about.
Response: On pages 6-7 is added a detailed description of the HVAC system. Ventilation system is ensured by air handling unit with heat recovery. The recovery unit can work with both fresh and circulating air. The air supply system was centrally set to 300 m3/h regardless of the number of users present. The measurements were carried out under these set conditions.
- Figure 5 is unclear – either make it more visible or delete it. It cannot be this way – if the boiler room is not part of your study (not in the room you made measurements) then I would suggest deleting the picture as it is not relevant to the study. It would be better to add some information about how the system works in the monitored meeting room.
Response: Figure 5, new number 4 is change with the high quality. Although some elements of the system are not important in relation to our research, they are part of the system as a whole and it would not be appropriate to leave them out of the technical scheme.
- Line 199: what does “under similar conditions” mean? – this is important as all the measured parameters depend on the occupancy schedule. Did you know how many people where in the meeting room during each week? Could it be that one heating system was better because there was less occupants during that period? This is crucial to the study.
Response: Meeting room was occupied by five people during the entire monitored week.
- Line 212: instead of “Figure (Fig. 7)” just put “Figure 7 shows”.
Response: Corrected.
- In line 302: In conclusion, it can be stated that both systems meet the requirements set by the Decree of the Ministry of Health of the Slovak Republic, but it is not clear from the obtained results which of the systems ensures a better quality of the indoor environment. – you will not be able to see which system is better if you did not study the occupant schedules.
Response: Thank you very much for the valuable comment. We will consider it in our next experimental research work.
- You say a lot about the IAQ and IEQ in the beginning of the article but then do not refer to them in the discussion or conclusions.
Response: Corrected.
Author Response File: Author Response.pdf
Reviewer 2 Report
The main remark is the lack or inability to demonstrate novelty in publications and research. After looking at the material, one gets the impression that an experiment has been performed and described, which confirms the dependencies known for years.
1.
„According to a study [24], buildings do not regularly operate at 75 an optimal level and often do not meet project forecasts. These failures affect energy effi-76 ciency, ensure adequate indoor environment quality (IEQ) and user satisfaction.”
Is this the only research on such a topic and with such results?
2.
„Operative temperature values were determined by calculation.”
Based on what equation? What temperature is it about? The description shows that the temperature was recorded and not calculated
3.
Measurements for 7 days (two series) at 30-minute intervals is a very small measurement test. Is it possible to make further series?
4.
Sections 2.1 - 2.6 are very detailed but add little to the overall experiment. The authors did not justify the advisability of presenting such precise information about the structure and features of the room and building.
5.
Figure 5 is of very poor quality and therefore cannot be assessed.
6.
„The 207 statistical evaluation given in table (Tab. 2) includes data collected during a 7-day contin-208 uous measurement for each of the monitored heating systems.”
Measurements with a time step of 30 minutes can hardly be called continuous.
7.
There is no news in chapter 3.1, no result is surprising, and the authors' comments confirm this belief.
8.
Figure 7 - It has been recognized for years that a graph with two axes is not the best solution for presenting data.
Perhaps it is worth showing and discussing temperature changes over 30-minute periods. Some of the temperature gains appear to be large and require explanation. Perhaps this will be an area where novelty will be revealed
9.
Figure 8 - It will be much more advantageous to present the results in two charts. The comment on the auxiliary axes is still valid (four graphs then, but two figures).
10.
There are numerous and detailed publications discussing the relationship between the number of people and indoor CO2 concentration. The conducted study confirms the current state of knowledge.
11.
Perhaps the authors should propose their own evaluation criteria for both systems, which will allow for their evaluation. Perhaps it will be valuable to supplement with the results of surveys collected from users of the room.
Author Response
Response to reviewer 2
We are thankful to the reviewer for your insightful comments which helped in improving the clarity of the work. We have revised the paper thoroughly according to your comments.
Reviewers' Comments:
- The main remark is the lack or inability to demonstrate novelty in publications and research. After looking at the material, one gets the impression that an experiment has been performed and described, which confirms the dependencies known for years.
Response: The results of measurements of indoor environmental quality parameters for various heating and ventilation systems are still insufficient in Slovakia, and it is necessary to carry out such monitoring and analyse the results.
- „According to a study [24], buildings do not regularly operate at 75 an optimal level and often do not meet project forecasts. These failures affect energy effi-76 ciency, ensure adequate indoor environment quality (IEQ) and user satisfaction.” Is this the only research on such a topic and with such results?
Response: The results of this study is presented in more detailed form.
- „Operative temperature values were determined by calculation.”
Based on what equation? What temperature is it about? The description shows that the temperature was recorded and not calculated
Response: WE measured the indoor air temperature, surface temperature, air velocity and the operative temperature was calculated according to equation:
θa - air temperature [°C]
θr,m - mean radiant temperature [°C]
Mean radiant temperature is determined according to measured surface temperature.
- Measurements for 7 days (two series) at 30-minute intervals is a very small measurement test. Is it possible to make further series?
Response: Parameters of IEQ were recorded in 1-minute intervals, only surface temperatures were recorded in 30-minutes intervals.
- Sections 2.1 - 2.6 are very detailed but add little to the overall experiment. The authors did not justify the advisability of presenting such precise information about the structure and features of the room and building.
Response: Description of the building and floor plans are changed. More information about HVAC system is added.
- Figure 5 is of very poor quality and therefore cannot be assessed.
Response: Figure 5 is changed.
- „The 207 statistical evaluation given in table (Tab. 2) includes data collected during a 7-day contin-208 uous measurement for each of the monitored heating systems.”
Measurements with a time step of 30 minutes can hardly be called continuous.
Response: Parameters of IEQ were recorded in 1-minute intervals, only surface temperatures were recorded in 30-minutes intervals. These recorded values of surface temperatures are sufficient for the calculation of operative temperature.
- There is no news in chapter 3.1, no result is surprising, and the authors' comments confirm this belief.
Response: Every research is a challenge and researchers expect some results. Sometimes the results can be surprising, other times just expected. Even such results are important for the further advancement of research, and it is important to present them.
- Figure 7 - It has been recognized for years that a graph with two axes is not the best solution for presenting data.
Response: All figures are improved.
- Perhaps it is worth showing and discussing temperature changes over 30-minute periods. Some of the temperature gains appear to be large and require explanation. Perhaps this will be an area where novelty will be revealed
Response:
Figure 8 - It will be much more advantageous to present the results in two charts. The comment on the auxiliary axes is still valid (four graphs then, but two figures).
Response: Corrected.
There are numerous and detailed publications discussing the relationship between the number of people and indoor CO2 concentration. The conducted study confirms the current state of knowledge.
Response: We agree with this statement.
Perhaps the authors should propose their own evaluation criteria for both systems, which will allow for their evaluation. Perhaps it will be valuable to supplement with the results of surveys collected from users of the room.
Response: At the beginning of the measurements, we assumed that dust concentrations would be higher in the case of a mechanical heating system, which causes higher air flow and creates higher vertical stratification. This assumption was not confirmed.
The company that occupies and owns the building deals with ventilation and air-conditioning, and therefore this company cares about regular maintenance and replacement of filters, and this was reflected in the low sublimit values of the monitored parameters. Here it was confirmed that the replacement of filters and regular maintenance and cleaning of the air handling system is necessary to maintain a high quality of the indoor environment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Thank you for submitting your paper to the journal 'buildings'.
My review opinion is as follow:
Abbreviations must be explained at the time of their first appearance. (e,g IEQ, NZEB..)
The list of measuring devices should be tabulated. Through this, it should be possible to determine the error range or resolution.
In Fig.3, 4 unnecessary layers (e.g. grids) of the floor plan should be removed, and dimensions and orientations should be clearly expressed.
It is necessary to further explain the method of setting the operative temperature of RH and MH and the reason for the difference.
Lines and text in Fig. 5 are blurry and unreadable.
Fig.8 is recommended to be expressed in a different way. Because the tests were not conducted simultaneously.
Since the target building is not newly constructed, the VOC result is bound to be the same. It would be a natural result.
In the results, it is necessary to present the outdoor environment data (temperature/humidity/PM). Especially in the case of PM, the external PM data at that time is important because this experiment was not conducted at the same time. This is because the indoor PM value is affected by the outdoor PM value.
Although the experiment was planned and performed and the results were presented, it is necessary to develop a method for presenting the results (Fig. table). The crucial problem is that the two results cannot be compared in absolute terms because the experiments were not conducted at the same time. Analysis of the results is also insufficient. An analysis based on the working principle of RH-MH is required.
Author Response
Response to reviewer 3
We are thankful to the reviewer for your insightful comments which helped in improving the clarity of the work. We have revised the paper thoroughly according to your comments.
Reviewers' Comments:
- Abbreviations must be explained at the time of their first appearance. (e,g IEQ, NZEB..)
Response: Corrected
- The list of measuring devices should be tabulated. Through this, it should be possible to determine the error range or resolution.
Response: Table with characteristics of measuring instruments are added to the manuscript.
- In Fig.3, 4 unnecessary layers (e.g. grids) of the floor plan should be removed, and dimensions and orientations should be clearly expressed.
Response: There is added new figure for the ground plan of the second floor (Figure 3).
- It is necessary to further explain the method of setting the operative temperature of RH and MH and the reason for the difference.
Response: WE measured the indoor air temperature, surface temperature, air velocity and the operative temperature was calculated according to equation:
θa - air temperature [°C]
θr,m - mean radiant temperature [°C]
Mean radiant temperature is determined according to measured surface temperature.
- Lines and text in Fig. 5 are blurry and unreadable.
Response: Figure 5 (actual number of Figure is 4) is improved and the text about the system function is added.
- 8 is recommended to be expressed in a different way. Because the tests were not conducted simultaneously.
Response: All the figures are changed. Results of the parameters are presented separately for radiant heating system and mechanical heating system for better visualization and understanding.
- Since the target building is not newly constructed, the VOC result is bound to be the same. It would be a natural result.
Response: We confirm that the building is not newly constructed. If only natural ventilation is ensured, the values could be higher and different. But in the case of mechanical ventilation, these values are in many cases below the quantification limits. This was also confirmed in our study.
- In the results, it is necessary to present the outdoor environment data (temperature/humidity/PM). Especially in the case of PM, the external PM data at that time is important because this experiment was not conducted at the same time. This is because the indoor PM value is affected by the outdoor PM value.
Response: The room was ventilated by a central air handling unit with filter technology with high efficiency (more than 99%), therefore outdoor PM concentrations do not affect the level of PM occurrence in the indoor environment.
- Although the experiment was planned and performed and the results were presented, it is necessary to develop a method for presenting the results (Fig. table). The crucial problem is that the two results cannot be compared in absolute terms because the experiments were not conducted at the same time. Analysis of the results is also insufficient. An analysis based on the working principle of RH-MH is required.
Response: All the figures are changed. Results of the parameters are presented separately for radiant heating system and mechanical heating system for better visualization and understanding.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Dear authors,
The article was improved according to the points from the 1st review
Although the quality of the paper still can be improved, if no additional requests are asked by the other reviewer/s, the paper can be accepted for publication after minor improvements to some of the figures.
This includes:
Fig. 1 it is not visible where the object is really located or situated. In its present form, this figure gives zero information to the reader.
Fig.4 is also not readable in its current form. Try to enlarge or rethink moving it to the appendix with a changed page orientation
Fig.5 please mark the sensors
Fig. 6 and 7 for a professional paper it is required to be clear and precise. Please unify the scales for those two figures for both temperature and humidity. Same for fig 8 and 9.
Author Response
Response to reviewer 1
We are thankful to the reviewer for your insightful comments which helped in improving the clarity of the work. We have revised the paper thoroughly according to your comments.
Round 2
Reviewers' Comments:
Dear authors,
The article was improved according to the points from the 1st review
Although the quality of the paper still can be improved, if no additional requests are asked by the other reviewer/s, the paper can be accepted for publication after minor improvements to some of the figures.
This includes:
- Fig. 1 it is not visible where the object is really located or situated. In its present form, this figure gives zero information to the reader.
Response: Thank you very much for note. The Figure 1 was changed.
- Fig. 4 is also not readable in its current form. Try to enlarge or rethink moving it to the appendix with a changed page orientation
Response: Thank you very much for note. The Figure 1 was changed and enlarged.
- Fig. 5 please mark the sensors
Response: Thank you very much for note. The Figure 5 was changed. Sensor was marked.
- Fig. 6 and 7 for a professional paper it is required to be clear and precise. Please unify the scales for those two figures for both temperature and humidity. Same for fig 8 and 9.
Response: Thank you very much for note. Figures was changed. Scales was unified.
Author Response File: 
Author Response.docx
Reviewer 2 Report
1. The authors did not explain the novelty or significance of the results obtained
2. There are formal errors in the diagram (Figure 4): the place of installation of the safety valves, connection of the heat source (no pipe is attached to the internal part)
Author Response
Response to reviewer 2
We are thankful to the reviewer for your insightful comments which helped in improving the clarity of the work. We have revised the paper thoroughly according to your comments.
Round 2
Reviewers' Comments:
- The authors did not explain the novelty or significance of the results obtained
Response: Thank you very much for note. This aim of this paper is to explore the specific IEQ factors under different heating conditions in meeting room of administrate building located in Kosice. In Slovakia, there is not enough measurement of IEQ to assess the extent to which building users are exposed to high concentrations. The second aim of the study is to shown that the central air handling unit with filter technology with high-efficiency (more than 99%) has low I/O ratios therefore outdoor PM concentrations do not affect the level of PM occurrence in the indoor environment. The novelty and significance of the results obtained is in their uniqueness.
- There are formal errors in the diagram (Figure 4): the place of installation of the safety valves, connection of the heat source (no pipe is attached to the internal part)
Response: Thank you very much for note. Figure 4 was changed.
Author Response File: Author Response.docx
Reviewer 3 Report
- In the results, it is necessary to present the outdoor environment data (temperature/humidity/PM). Especially in the case of PM, the external PM data at that time is important because this experiment was not conducted at the same time. This is because the indoor PM value is affected by the outdoor PM value. "Response: The room was ventilated by a central air handling unit with filter technology with high efficiency (more than 99%), therefore outdoor PM concentrations do not affect the level of PM occurrence in the indoor environment." >> The target room has a window facing the outside. If this window is not 100% airtight, outside air will affect the interior. In this measurement, the outside air necessarily affects the indoor environment.
- Analysis of the results is also insufficient. An analysis based on the working principle of RH-MH is still required.
Author Response
Response to reviewer 3
We are thankful to the reviewer for your insightful comments which helped in improving the clarity of the work. We have revised the paper thoroughly according to your comments.
Round 2
Reviewers' Comments:
- In the results, it is necessary to present the outdoor environment data (temperature/humidity/PM). Especially in the case of PM, the external PM data at that time is important because this experiment was not conducted at the same time. This is because the indoor PM value is affected by the outdoor PM value. "Response: The room was ventilated by a central air handling unit with filter technology with high efficiency (more than 99%), therefore outdoor PM concentrations do not affect the level of PM occurrence in the indoor environment." >> The target room has a window facing the outside. If this window is not 100% airtight, outside air will affect the interior. In this measurement, the outside air necessarily affects the indoor environment.
Response: Thank you very much for note. The outdoor environment data and analysis (temperature/humidity/PM) was added.
- Analysis of the results is also insufficient. An analysis based on the working principle of RH-MH is still required.
Response: Thank you very much for note. The analysis was added on page 17.
Author Response File: Author Response.docx
Round 3
Reviewer 3 Report
1. Figures 6, 7, 10, 11, 12, and 13 show two similar graphs. The two graphs in Figures 6, 11, 12, and 13 display the same data, and the two graphs in Figures 7 and 10 are similar but display different data. I don't understand why two similar or different graphs are displayed.
2. The title of Table 5 should be more specific, and the unit is omitted in Figure 15.
3. It is necessary to specify the measuring device and method of outdoor air data (temperature, humidity, PM). If the data from the Korea Meteorological Agency is surveyed, there is a lack of connection with indoor data. In particular, PM needs to be directly measured at the target site as it is related to microclimate.
4. Analysis of results based on MH/RH system characteristics is still insufficient. And there are only graphs on page 17.
5. It is difficult to understand the contents of the paper due to the lack of consistency between the method of expressing the measurement data on the graph and the graph expression (title, axis expression, etc.)
Author Response
Response to reviewer 3
We are thankful to the reviewer for the insightful comments which helped in improving the clarity of the work. We have revised the paper thoroughly according to the comments.
Round 3
Reviewers' Comments:
- Figures 6, 7, 10, 11, 12, and 13 show two similar graphs. The two graphs in Figures 6, 11, 12, and 13 display the same data, and the two graphs in Figures 7 and 10 are similar but display different data. I don't understand why two similar or different graphs are displayed.
Response: Thank you very much for note. Manuscript was previously submitted with tracking changes in form of Word (docx). This displayed both the original Figures and the Figures that were (removed) replaced with modified ones in the document. That's why the Figures were listed twice in the manuscript. The top Figure is the old one and the bottom is the new one. We apologize for the insufficient explanation of the updated version. Now we submit pdf document without tracking changes.
- The title of Table 5 should be more specific, and the unit is omitted in Figure 15.
Response: Thank you very much for the note. The title of Table 5 was changed and the unit in Figure 15 was added.
- It is necessary to specify the measuring device and method of outdoor air data (temperature, humidity, PM). If the data from the Korea Meteorological Agency is surveyed, there is a lack of connection with indoor data. In particular, PM needs to be directly measured at the target site as it is related to microclimate.
Response: Thank you very much for note. Data is not from the Korea Meteorological Agency, but from Slovak hydrometeorological institute (Slovenský hydrometeorologický ústav) (https://aqicn.org/city/slovakia/kosice/amurska/).
The Slovak Hydrometeorological Institute (SHMU) is a specialized organization performing hydrological and meteorological services at the national and international level. The activity of SHMU is mainly governed by Act 201/2009 Coll. on the state hydrological service and the state meteorological service. The Slovak Hydrometeorological Institute was established on January 1, 1969 by the Ministry of Forestry and Water Management. SHMU had been continued the meteorological and hydrological service, which had been operating on the territory of Slovakia since approximately the middle of the 19th century. Currently, SHMU is an organization within the scope of the Ministry of the Environment of the Slovak Republic. The method of financing SHMU determines its inclusion among contributory organizations. SHMU monitors the quantitative and qualitative parameters of the state of air and water in the territory of the Slovak Republic, collects, verifies, evaluates, archives and interprets data and information about the state and regime of air and water, describes incidents in the atmosphere and hydrosphere, creates and issues meteorological and hydrological forecasts, alerts and information. It provides data, information and study results to professionals and the public. The basic facilities for obtaining data on quantitative and qualitative parameters of air and /or water are the observation objects of the state hydrological and state meteorological network in a total number of 3,884.
The investigated ABC office building is only 1.26 km away from the SHMU measuring station, therefore we did not make outdoor air quality measurements with our intruments.
- Analysis of results based on MH/RH system characteristics is still insufficient. And there are only graphs on page 17.
Response: Thank you very much for note. Manuscript was previously submitted with tracking changes in form of Word (docx). The analysis of result based on MR/RH system characteristic was on page 17 in doc but in page 19 in pdf. We apologize for the misunderstanding.
We were adding text:
Table 5 presents I/O ratio for PM2.5 and PM10 concentrations during radiant and mechanical heating. Ratio values between Indoor and Outdoor (I/O) concentrations have been widely used to study the relationship between indoor and outdoor concentrations of pollutants [37]. The I/O ratio was less than 1 during all measurement days, which means that the amount of PM2.5 and PM10 concentration in the outdoor environment was higher, so they can be a source of PM in the indoor environment of buildings. The I/O ratio for PM2.5 ranges from 0.02-0.2 and for PM10 ranges from 0.2-0.44 for RHS. The I/O ratio of PM2.5 and PM10 ranges from 0.03 to 0.16 and from 0.01 to 0.46 for MHS, respectively. The results show that room ventilated by a central air handling unit with filter technology with high-efficiency (more than 99%) achieved low I/O ratios therefore outdoor PM concentrations should not have affected the level of PM occurrence in the indoor environment. In the study of Kridlova Burdova et al. [38], aimed on monitoring of air-conditioned university library also in Kosice, Slovakia showed that I/O ratio of PM10 was within range of 7.1-31.43 which is higher by 97.2%-98.6% for RHS and 98.5%-99.8% for MHS compared to the results of PM10 in this study and the authors proposed to design high efficiency HEPA filters with an efficiency of up to 99.97%. This present study also confirms the need of using filters with the highest level of separation. It should also be noted that regular care and replacement of filters must be taken care of, so that the filters do not become the source of pollutants. This study also points to the necessity of using fresh air units with a stream of fresh air. Combining this measure with a suitable heating system can significantly contribute to reducing PM concentrations. Radiant heating is the method with the lowest level of air and dust swirling. Mechanical heating can be characterized as a heating with a higher risk of air swirling and dust spreading, nevertheless often used due to the possibility of bringing fresh air into a ventilated room with occupants.
- It is difficult to understand the contents of the paper due to the lack of consistency between the method of expressing the measurement data on the graph and the graph expression (title, axis expression, etc.)
Response: Thank you very much for note. We improved the graphs.
Author Response File: Author Response.docx
