Integrating the Living Wall with Mechanical Ventilation to Improve Indoor Thermal Environment in the Transition Season

Reviewer 1: Passive cooling and purification of living walls is important for energy saving, carbon reduction and comfort in the built environment. The authors further investigate the performance of this system in the transition season based on previous summer studies. This provides a more complete basis for the application of this system.

Response: Thank you for your positive evaluation and all your comments on my manuscript, which are extremely helpful in improving the paper quality. According to your comments, we tried our best to make the appropriate revision and all changes were highlighted in the green color for the easy reference in the revised manuscript.

Comment 1: However, I have a question about the control group: why was Room A not equipped with a natural or mechanical ventilation device? This may have contributed to the difference in ventilation rates and indoor environments.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

In the design of the experiment, the selection of the control group was critical, and room A was not installed with natural or mechanical ventilation to simulate a common real-world scenario that many buildings may not actively activate ventilation during the transition season. This design can better reflect the actual environment, so as to improve the reliability and applicability of the research results.

Comment 2: In addition, window airtightness is suggested to be stated.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

Addition<<

Before the experiment, the Windows and other parts of the laboratory are sealed with rubber seals to prevent the penetration of air or water vapor and affect the results of the experiment.

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Reviewer 2: The article titled “Integrating the Living Wall with Mechanical Ventilation to Improve Indoor Thermal Environment in The Transition Season” studies the effect of the LW-V system on the indoor environment and thermal comfort during the transition season. There are guiding significance for the improvement of human thermal comfort in the transitional season.  However, the format of the manuscript is confusing, and there is a lot of information that needs to be corrected.  Some specific comments are as follows：

Response: Thank you for your positive evaluation and all your comments on my manuscript, which are extremely helpful in improving the paper quality. According to your comments, we tried our best to make the appropriate revision and all changes were highlighted in the blue color for the easy reference in the revised manuscript.

Comment 1: The manuscript contains a large number of journal requirements, explanatory texts, and non-journal body text, such as the first paragraph of the introduction (Lines 24-32), and the headings of Figure 1, Table 1, and 2.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

the first paragraph of the introduction (Lines 24-32) has been revised.

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Figure 1. This is a figure. Schemes follow the same formatting.

Table 1. This is a table. Tables should be placed in the main text near to the first time they are cited.

Table 2. This is a table. Tables should be placed in the main text near to the first time they are cited.

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Figure 1. (a) Schematic diagram of LW-V system, (b) the figure of experimental set up.

Table 1. Testing range and accuracy of experimental instruments.

Table 2. The scales of questionnaire physiological indicators parameters.

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Comment 2: Lines 118-124 are less relevant to the subject matter of this article and are recommended to be modified.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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In addition, indoor plants may have adverse effects on indoor environment. When introduced indoors, plants, especially those with scented leaves or flowers, may release biogenic volatile organic compounds (VOCs) and contribute to indoor environmental pollution [34]. Irga et al. [35] suggested that potted plants could potentially introduce indoor pathogenic bacteria, but the presence of pathogenic microorganisms in potted mixtures does not necessarily result in an increased concentration of spores from these taxonomic units within indoor plants. Research indicates that active green walls may create a conducive environment for the growth of pathogenic fungal or bacterial species. While potted soil is known to be a source of human pathogens, studies on the aerosolized dispersal of fungal pathogens from contaminated indoor soil remain limited [36].

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In addition, indoor plants may have adverse effects on indoor environment. When introduced indoors, plants, especially those with scented leaves or flowers, may release biogenic volatile organic compounds (VOCs) and contribute to indoor environmental pollution [34]. The emission of these VOCs can result in a deterioration of indoor air quality, thereby exerting detrimental effects on human health. Consequently, when incorporating indoor plants, meticulous selection of plant species is imperative to mitigate the impact of VOCs.

Comment 3: The innovation of this manuscript is the LW-V system or the application effect of the system in the transition season? If it is the former, it is recommended to revise the last paragraph of the introduction, otherwise, it is recommended to emphasize the characteristics of the transition season and discuss and compare as much as possible.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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In summary, plants can contribute to the enhancement of indoor thermal conditions. In the aforementioned studies, many focus on either winter or summer seasons, with limited research on transitional seasons. The transitional season refers to the period between spring and autumn when temperatures gradually become warmer or colder, marking the transition from winter to summer or vice versa. During this season, significant changes in temperature, humidity, and other climatic factors may affect indoor thermal comfort. In this study, a living wall was integrated with a ventilation system (LW-V system) to investigate its specific impact on the indoor thermal environment during the transition season from summer to winter, as well as its potential for improving indoor CO₂ concentration. Additionally, the subjective perception and expectations of indoor environments were assessed by conducting a questionnaire survey in conjunction with measuring skin temperatures at eight locations for 60 subjects.

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In summary, plants can contribute to the enhancement of indoor thermal conditions. In this study, a living wall was integrated with a ventilation system (LW-V system) to investigate its specific impact on the indoor thermal environment during the transition season from summer to winter, as well as its potential for improving indoor CO₂ concentration. Additionally, the subjective perception and expectations of indoor environments were assessed by conducting a questionnaire survey in conjunction with measuring skin temperatures at eight locations for 60 subjects.

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Comment 4: Line 140, it is recommended to describe the detailed parameters of the wind turbine system, because the wind speed and related feelings in the results are caused by the fan system.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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Figure 1 gives a diagram of the experimental system, the experimental system mainly consists of three parts: a fan system (200D-19DP), a wooden box and green plants (Epipremnum aureum) with the size of 1000mm (Length), 300mm (Width) and 2000mm (Height).

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Figure 1 gives a diagram of the experimental system, the experimental system mainly consists of three parts: a fan system (ST-200D-19DP), a wooden box and green plants (Epipremnum aureum) with the size of 1000mm (Length), 300mm (Width) and 2000mm (Height). The ST-200D-19DP is a low-noise air supply fan system featuring dimensions of 650mm in length, 470mm in width, and 360 mm in height. It offers dual power settings of 155/120W, air volume of 690/560 m³/h, pressure outputs of 200/190 Pa, and operates at a low noise level of 33/29 dB(A) while requiring 220V voltage.

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Comment 5: More detailed information about the epipremnum aureum should be given, such as the number of plants, size, etc.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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The study by Ding et al. [37] showed that Epipremnum aureum were the most suitable plants to be grown indoors, either under sufficient or insufficient light conditions. In addition, the fan system passed through the aluminum foil tube, the airtight box, and the surface of plants, and then sent the air out. Because of the repair and transpiration of plants, it can play a role in filtering and improving the indoor thermal environment.

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The study by Ding et al. [37] showed that Epipremnum aureum were the most suitable plants to be grown indoors, either under sufficient or insufficient light conditions. In this study, a total of 104 pots of Epipremnum aureum with an average height of about 25cm were used to ensure their proper distribution and layout on vertical walls. In addition, the fan system passed through the aluminum foil tube, the airtight box, and the surface of plants, and then sent the air out. Because of the repair and transpiration of plants, it can play a role in filtering and improving the indoor thermal environment.

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Comment 6: Here are some questions about experimental design:

  1) The title of the article includes the transition season, and the last paragraph of the introduction emphasizes that there are few studies on the transition season, why is the study on environmental monitoring and human subjective thermal comfort both 1-2 weeks, and this time range is sufficient?

2) Why is environmental monitoring carried out separately from the subjective questionnaire? Environmental parameters are usually monitored at the same time as thermal comfort studies. This can be discussed with Sections 283-286.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

First, based on the experience of previous studies, a study period of 1-2 weeks has been shown to yield reliable results. Second, a study period of 1-2 weeks can cover the changing trends of the transition season, and also avoid the time and cost pressure of long-term data collection.

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In order to investigate the effect of the LW-V system on the indoor thermal environment and comfort during the transition season, objective measurements and subjective questionnaires from the subjects were used in the experiment. The indoor environmental parameters of both rooms were monitored during the comparison experiment, including four parameters: indoor temperature, relative humidity, air speed, and CO₂ concentration. The instruments were all placed on a round table in the center of the room, and the data were recorded through the instruments with the time interval set to 5 min/time.

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In order to investigate the effect of the LW-V system on the indoor thermal environment and comfort during the transition season, objective measurements and subjective questionnaires from the subjects were used in the experiment. The indoor environmental parameters of both rooms were monitored during the comparison experiment, including four parameters: indoor temperature, relative humidity, air speed, and CO₂ concentration. While subjective questionnaires collected participants’ personal feelings and evaluations. In this study, the environment and subjective questionnaire are studied separately for mainly the following reasons: (1) Environmental monitoring and subjective questionnaires are two different methods of data acquisition. They are conducted separately to ensure the independence of objective and subjective data and to avoid interference between them. (2) The separation of environmental monitoring and subjective questionnaires simplifies the research design and implementation process, making each stage more independent and controllable in operation. This helps ensure the accuracy and reliability of data while enhancing the scientific rigor of the study. The instruments were all placed on a round table in the center of the room, and the data were recorded through the instruments with the time interval set to 5 min/time.

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Comment 7: There are a lot of complete repetitions of the same content in the manuscript, such as:

  1) The title of Figure 3 is a copy of the name of Figure 2;

2) The title of Table 2 is copies of the names in Table 1;

3) Figure 9 is an exact repetition of Figure 8;

4) lines 292-299 are the same as lines 243-250;

5) The title of Figure 15 is missing, and the name of Figure 14 is repeated twice.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

1) From<<

Figure 3. (a) Schematic layout of the laboratory, (b) the actual view of the experimental system.

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Figure 3. Schematic distribution of human skin temperature measurement points.

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2) From<<

Table 1. This is a table. Tables should be placed in the main text near to the first time they are cited.

Table 2. This is a table. Tables should be placed in the main text near to the first time they are cited.

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Table 1. Testing range and accuracy of experimental instruments.

Table 2. The scales of questionnaire physiological indicators parameters.

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3) From<<

Figure 8. Meteorological station data during the experimental period

Figure 9. Meteorological station data during the experimental period

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Figure 8. Comparison of indoor air speeds in Room A and Room B during the transition season

Figure 9. Comparison of indoor CO₂ concentrations in Room A and Room B during the transition season

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Indoor temperature and relative humidity are both important indicators of the thermal environment in the evaluation room and important factors affecting indoor thermal comfort. Figure 7 shows the comparison of temperature and relative humidity in Room A and Room B during the transition season. From the temperature perspective, the indoor temperature in Room A ranged from 22℃ to 37℃ with an average value of 30.69℃. The indoor temperature in Room B ranged from 21℃ to 34℃ with an average value of 29.24℃. It showed the LW-V system lowered indoor air temperature by 1.45℃, which is due to the removal of heat from the air by plant transpiration.

Human thermal sensation was related to human skin temperature, and it was an important physiological indicator to characterize the thermal physiological response of the human body. Therefore, the skin temperature of the subjects was monitored in this experiment. Considering the operability of the experiment, the 8-point test method was adopted [38], and the measurement sites were forehead, chest, back, upper arm, forearm, hand, thigh, and shank in that order. Then the mean skin temperature was obtained by weighted average of the skin temperature of each part, and the weighted calculation formula was as follows:

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Human thermal sensation was related to human skin temperature, and it was an important physiological indicator to characterize the thermal physiological response of the human body. Therefore, the skin temperature of the subjects was monitored in this experiment. Considering the operability of the experiment, the 8-point test method was adopted [38], and the measurement sites were forehead, chest, back, upper arm, forearm, hand, thigh, and shank in that order. Then the mean skin temperature was obtained by weighted average of the skin temperature of each part, and the weighted calculation formula was as follows:

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Figure 14. Comparison of indoor air freshness sensation voting in Room A and Room B during transitional season.

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Figure 15. Comparison of indoor thermal comfort level voting in Room A and Room B during transitional season.

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Comment 8: It is suggested that the references of subjective evaluation indicators should be added.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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In the questionnaire survey, three main aspects were included: the basic information of the subjects, the indoor environment assessment and the acceptability of the LW-V system. The indoor environment assessment mainly covered the aspects of thermal sensation, humid sensation, air speed sensation, air freshness and thermal comfort in the room. As shown in Table 2, the thermal sensation, humid sensation and thermal comfort level were based on the 7-point scale. The indoor air freshness and acceptance level was based on the 5-point scale. The air speed sensation was based on the 4-point scale.

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In the questionnaire survey, three main aspects were included: the basic information of the subjects, the indoor environment assessment and the acceptability of the LW-V system. The indoor environment assessment mainly covered the aspects of thermal sensation, humid sensation, air speed sensation, air freshness and thermal comfort in the room. As shown in Table 2, according to ASHRAE standards [36], the thermal sensation, humid sensation and thermal comfort level were based on the 7-point scale. The indoor air freshness and acceptance level was based on the 5-point scale. The air speed sensation was based on the 4-point scale. This method allows for direct understanding of the subjects' thermal sensation and comfort level at that time.

[36] Song J.W.; Study on the Influence of Architectural Space Scale on Human Thermal Comfort [D]. Tianjin University, 2017.

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Comment 9: Explain the calculation process or reference of the neutral skin temperature of 33.2 °C.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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Calculated by the formula, the MST of subjects in Room A was 33.31℃, that of subjects in Room B was 33.13℃. and that of subjects in Room B was 0.18℃ lower than that in Room A, as shown in Figure 10. The experimental results showed that the MST of the subjects in Room B was closer to the neutral MST of 33.2℃, which indicated that the LW-V system play a role in regulating the thermal comfort of the room during the transition season.

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Calculated by the formula, the MST of subjects in Room A was 33.31℃, that of subjects in Room B was 33.13℃. and that of subjects in Room B was 0.18℃ lower than that in Room A, as shown in Figure 10. The experimental results showed that the MST of the subjects in Room B was closer to the neutral MST of 33.2℃. A clear linear correlation exists between skin temperature and thermal sensation, with the term 'neutral skin temperature' referring to the specific skin temperature at which thermal sensation is perceived as neutral [38]. The experimental results demonstrate that the LW-V system effectively regulates the thermal comfort of the room during the transitional season.

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Comment 10: The description is inaccurate, and "(b)" is missing in Figure 7.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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From the relative humidity, the LW-V system obviously increased the indoor relative hu-midity. The indoor relative humidity of Room A maintained in the range of 35%-77%, the average relative humidity of Room A was 51.32%. The relative humidity of Room B main-tained in the range of 56%-84%, and the average relative humidity was 70.42%, the relative humidity of Room B was 19.1% higher than Room A. Through transpiration, water is transported from the roots to the leaves of plants, where it undergoes a phase change into water vapor and is subsequently released into the atmosphere. In summary, the LW-V system demonstrated a significant humidity regulation effect in the experiment. The nota-ble increase in humidity can be primarily attributed to the transpiration and water evap-oration processes of the plants. These natural mechanisms contribute to the augmentation of airborne moisture content, consequently elevating the indoor relative humidity.

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As shown in Figure 7 (b), the LW-V system obviously in-creased the indoor relative humidity. In Room A, the indoor relative humidity was maintained within the range of 35% to 77%, with an average of 51.32%. Similarly, in Room B, the relative humidity ranged from 56% to 84%, with an average of 70.42%. The average relative humidity in Room B is approximately 19.1% higher than that in Room A, mainly due to the transpiration of plants and water evaporation processes. These natural mechanisms effectively augment air moisture content and consequently elevate relative humidity levels. In summary, the LW-V system has exhibited a notable capacity for regulating humidity in the experiment.

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Comment 11: Punctuation, font, capitalization, e.g. line 312.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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Calculated by the formula, the MST of subjects in Room A was 33.31℃, that of sub-jects in Room B was 33.13℃. and that of subjects in Room B was 0.18℃ lower than that in Room A, as shown in Figure 10. The experimental results showed that the MST of the subjects in Room B was closer to the neutral MST of 33.2℃, which indicated that the LW-V system play a role in regulating the thermal comfort of the room during the transition season.

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Calculated by the formula, the MST of subjects in Room A was 33.31℃, that of subjects in Room B was 33.13℃. And that of subjects in Room B was 0.18℃ lower than that in Room A, as shown in Figure 10. The experimental results showed that the MST of the subjects in Room B was closer to the neutral MST of 33.2℃, which indicated that the LW-V system play a role in regulating the thermal comfort of the room during the transition season.

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Comment 12: Modify the upper arm format in Figure 10.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

Comment 13: This article is similar to the author's article published in Building and Environment in 2022 (Xi Meng, Lianyu Yan, Fudan Liu. A new method to improve indoor environment: Combining the living wall with air-conditioning. Building and Environment, 2022, 216:108981). In the current manuscript, a fan system is used, while the latter uses an air conditioning system. However, the results of the study are quite different, such as the changed trend in relative humidity and average skin temperature, and if relevant comparisons and discussions can be made, the quality of the article will be improved.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

Addition<<

  Contrary to the findings of this study, Meng et al. found that in their research combining a living wall with air-conditioning. The average relative humidity in Room A was 86%, which is 2.6% higher than Room B's 84.3%. This difference can be attributed to the higher atmospheric humidity levels during summer in Qingdao. By utilizing the strong vitality of plants and reducing watering frequency, indoor air can naturally absorb moisture and alleviate indoor humidity.

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Reviewer 3:

Response: Thank you for your positive evaluation and all your comments on my manuscript, which are extremely helpful in improving the paper quality. According to your comments, we tried our best to make the appropriate revision and all changes were highlighted in the orange color for the easy reference in the revised manuscript.

Comment 1: The text in the introduction formulates several correct statements; however, references [1-3] cannot be the basis for drawing such conclusions. Commented references contain similar statements based on the literature. Sources [1-3] should be better selected.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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Zou J.L.; Meng X. Investigating the effect of distribution form of copper foam fins on the thermal performance improvement of latent thermal energy storage units. Int. Commun. Heat Mass Transfer. 2023, 140, 106571

Gao Y.; Meng X. A comprehensive review of integrated phase change materials in building bricks: methods, performance and applications. J. Energy storage, 2023, 62, 106913

Paull N.J.; Irga P.J.; Torpy F.R. Active green wall plant health tolerance to diesel smoke exposure, Environ. Pollut., 2018, 240, 448-456.

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Zhao P.J.; Zhang M.Z. The impact of urbanisation on energy consumption: A 30-year review in China, Urban Climate, 24, 2018, 940-953, 2212-0955.

Feng Y.D.; Yuan H.X. Liu Y.B., The energy-saving effect in the new transformation of urbanization, Economic Analysis and Policy, 78, 2023, 41-59.

Rentschler J.; Leonov, N. Global air pollution exposure and poverty. Nat Commun 14, 2023, 4432.

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Comment 2: The experiment itself is described in insufficient detail. The intensity of ventilation is unknown. The illumination intensity during the experiments is unknown. Based on Figure 1, the lighting intensity can be estimated (with a significant error) at ~ 200 lux (which could correspond to ~5µmol/(m2s) of PAR (photosynthetic active radiation). At such low light, ornamental plants (including Epipremnum aureum) are on the border of photosynthesis and photorespiration.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

Addition<<

The photosynthetic light source of the living wall is derived from natural sunlight entering through the south-facing windows. The light intensity in both rooms ranges from 500 to 1500 lx, which satisfied the requisite level for plant photosynthesis.

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Comment 3: The presented CO₂ concentration results are unclear. In typical offices or similar rooms, CO₂ concentrations of approximately 1000 ppm are observed during use. The presented value of ~ 500 ppm indicates that ventilation must be approximately 5-6 times more intense than in commonly encountered conditions. Unfortunately, the lack of data on outdoor CO₂ concentration prevents a more precise estimate.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

The monitoring of CO₂ concentration is indeed one of the important indicators for assessing indoor air quality. In our study, the measured CO₂ concentration was indeed lower than the typical levels found in office environments.  As you pointed out, the lack of data on outdoor CO₂ concentrations limits the accurate estimation of indoor ventilation requirements. Future research can strengthen the monitoring of outdoor CO₂ concentrations to determine ventilation needs more accurately and further optimize management and control measures for indoor air quality.

Comment 4: Turning on mechanical ventilation probably changes the type of air exchange in the room from the typically assumed mixed ventilation to local supply (or personal ventilation).

Response: Thank you for your comment, which is valuable and needed to be illustrated.

 Changing natural ventilation to mechanical ventilation during the transition season can provide a more comfortable environment for people

Comment 5: The discussion of the results should include comments on which observed effects are the result of using green wall and which are rather the result of mechanical ventilation (separately for temperature, humidity, movement speed, CO₂ concentration, etc. ).

Response: Thank you for your comment, which is valuable and needed to be illustrated.

indoor temperature:

From the temperature perspective, the indoor temperature in Room A ranged from 22℃ to 37℃ with an average value of 30.69℃. The indoor temperature in Room B ranged from 21℃ to 34℃ with an average value of 29.24℃. It showed the LW-V system lowered indoor air temperature by 1.45℃, which is due to the removal of heat from the air by plant transpiration. In addition, the use of mechanical ventilation not only enhances air circulation, but also facilitates convective heat transfer and promotes evaporation, thereby effectively reducing indoor temperature and enhancing overall comfort.

indoor relative humidity:

As shown in Figure 7 (b), the LW-V system obviously in-creased the indoor relative humidity. In Room A, the indoor relative humidity was maintained within the range of 35% to 77%, with an average of 51.32%. Similarly, in Room B, the relative humidity ranged from 56% to 84%, with an average of 70.42%. The average relative humidity in Room B is approximately 19.1% higher than that in Room A, mainly due to the transpiration of plants in the living wall and water evaporation processes. These natural mechanisms effectively augment air moisture content and consequently elevate relative humidity levels. In summary, the LW-V system has exhibited a notable capacity for regulating humidity in the experiment. Contrary to the findings of this study, Meng et al. found that in their research combining a living wall with air-conditioning. The average relative humidity in Room A was 86%, which is 2.6% higher than Room B's 84.3%. This difference can be attributed to the higher atmospheric humidity levels during summer in Qingdao. By utilizing the strong vitality of plants and reducing watering frequency, indoor air can naturally absorb moisture and alleviate indoor humidity.

indoor air speed:

In addition to indoor temperature and relative humidity, indoor air speed was also one of the factors affecting indoor thermal comfort. Figure 8 compares the indoor air speed of Room A and Room B during the experiment, it can be seen from the figure that there was no fresh air volume in Room A, while the air speed in Room B was maintained at 0.2m/s-0.65m/s. And the average air speed in Room B was 0.37m/s. This is due to mechanical ventilation, which speeds up the indoor air flow. The proper airflow can play a role in accelerating the indoor air circulation and updating the indoor air, thus creating a more comfortable indoor environment.

CO₂ concentration:

It showed which was 13.83ppm lower than the average CO₂ concentration in Room A. This is because the plants in Room A photosynthesize and absorb CO₂ from the room. The photosynthetic efficiency of plants was related to the indoor CO₂ concentration. In a real indoor space, human respiration leads to an increase in CO₂ levels. Therefore, it can be inferred that the CO₂ absorption rate of LW-V system will be elevated, which showed that Room B had the potential to effectively enhance and improve indoor air quality through plant-mediated photosynthetic processes.

Comment 6: It should also be noted that the observed effect of reducing CO2 concentration is minimal, lower than the device's measurement accuracy (when measuring CO2 concentrations of approximately 500 ppm, the measurement error is 25 ppm—5% of the measured value). Formulating the conclusion (1) .... and "significantly mitigated CO2 concentration levels" is unjustified. More generally, there is no point in presenting data measured with an accuracy of 25 ppm with two decimal digits (it suggests false precision of measurements).

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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(1) During the transitional season, LW-V system played a pivotal role in enhancing the indoor thermal environment. It effectively reduced the average room temperature by 1.45℃, increased relative humidity by 19.1%, regulated indoor air speed within the range of 0.2m/s-0.65m/s, and significantly mitigated CO₂ concentration levels.

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(1) During the transitional season, LW-V system played a pivotal role in enhancing the indoor thermal environment. It effectively reduced the average room temperature by 1.45℃, increased relative humidity by 19.1%, regulated indoor air speed within the range of 0.2m/s-0.65m/s, and CO₂ concentration levels were slightly lower.

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Comment 7: Unfortunately, the submitted text has not been subjected to a proper editorial check. Below are some examples of gross inattention.

The summary's beginning is just information from the template and should under no circumstances appear in the text submitted for checking.

Tables 1 and 2 do not have original titles. Information from the document formatting pattern was left in place of the titles.

The captions of figures 6, 7, and 8, which sound identical, should be detailed. Note: the use of the term "meteorological" may incorrectly imply that measurements are taken outside the building)

Response: Thank you for your comment, which is valuable and needed to be illustrated.

The text has been checked and modified.

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Table 1. This is a table. Tables should be placed in the main text near to the first time they are cited.

Table 2. This is a table. Tables should be placed in the main text near to the first time they are cited.

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Table 1. Testing range and accuracy of experimental instruments.

Table 2. The scales of questionnaire physiological indicators parameters.

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Figure 8. Meteorological station data during the experimental period

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Figure 8. Comparison of indoor air speeds in Room A and Room B during the transition season.

Figure 6 illustrates the parameters of the meteorological station, serving as a reference for comparison. Furthermore, cross-referencing indoor monitoring data with outdoor meteorological parameters can substantiate the precision and dependability of experimental findings.

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Comment 8: It also has no title. Subsection 2.1 "Subsection" is a phrase from the document template that should be corrected.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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2.1. Subsection

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2.1. Description of the LW-V system

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Comment 9: The authors freely use the designation of carbon dioxide as CO₂ or CO₂ (correctly).

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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Plants can reduce the concentration of CO2 indoors through photosynthesis, and in a study by Tudiwer et al. [17], the CO2 concentration in classrooms with green plants decreased faster, plants were the only cause of the difference in CO2 concentration, and when the initial concentration of CO2 indoors was the same, the concentration of CO2 in classrooms with living wall system decreased by 3.5% faster than that in classrooms without plants. Torpy et al. [18] investigated the CO2 removal potential of eight common indoor plants and showed that the photosynthetic capacity of different plants varied at indoor light levels, that there were significant differences in the CO2 removal rates of different plants, that higher increases in CO2 removal rates were detected only at higher than indoor light levels, and that appropriate light could optimise CO2 uptake by plants. Vegetables are grown vertically to increase the net photosynthetic rate in a study by Shao et al [19]. And in an office with 1-3 staff and an area of 30m2, 100 plants grown vertically reduced indoor CO2 concentrations by 25.7-34.3% compared with no planting. As confirmed by Ding et al. [15], living wall system can reduce CO2 concentrations by 49 ppm in air-conditioned offices. Meng et al. [13] combined a living wall system with an air-conditioning system, and achieved a CO2 reduction of about 10% in an unoccupied environment compared to the room referred to, suggesting that in a real-space the potential of living walls to reduce indoor CO2 concentration would be improved.

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Plants can reduce the concentration of CO₂ indoors through photosynthesis, and in a study by Tudiwer et al. [17], the CO₂ concentration in classrooms with green plants decreased faster, plants were the only cause of the difference in CO₂ concentration, and when the initial concentration of CO₂ indoors was the same, the concentration of CO₂ in classrooms with living wall system decreased by 3.5% faster than that in classrooms without plants. Torpy et al. [18] investigated the CO₂ removal potential of eight common indoor plants and showed that the photosynthetic capacity of different plants varied at indoor light levels, that there were significant differences in the CO₂ removal rates of different plants, that higher increases in CO₂ removal rates were detected only at higher than indoor light levels, and that appropriate light could optimise CO₂ uptake by plants. Vegetables are grown vertically to increase the net photosynthetic rate in a study by Shao et al [19]. And in an office with 1-3 staff and an area of 30m², 100 plants grown vertically reduced indoor CO₂ concentrations by 25.7-34.3% compared with no planting. As confirmed by Ding et al. [15], living wall system can reduce CO₂ concentrations by 49 ppm in air-conditioned offices. Meng et al. [13] combined a living wall system with an air-conditioning system, and achieved a CO₂ reduction of about 10% in an unoccupied environment compared to the room referred to, suggesting that in a real-space the potential of living walls to reduce indoor CO₂ concentration would be improved.

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In order to investigate the effect of the LW-V system on the indoor thermal environment and comfort during the transition season, objective measurements and subjective questionnaires from the subjects were used in the experiment. The indoor environmental parameters of both rooms were monitored during the comparison experiment, including four parameters: indoor temperature, relative humidity, air speed, and CO2 concentration. The instruments were all placed on a round table in the center of the room, and the data were recorded through the instruments with the time interval set to 5 min/time.

The experiment was conducted from September 17 to 30, 2023. During the experiment, the time period of 8:30-17:30 was selected according to the office hours. The temperature, relative humidity, air speed, and CO2 concentration of the indoor environment were measured and analyzed by the four environmental variables that affect human thermal comfort. The questionnaire survey was conducted from 9:00-10:20, 10:40-12:00, 13:00-14:20 and14:40-16:00 between October 5th and October 12th, 2023. Considering the airtightness of the two rooms, both rooms were kept closed during the experimental period to avoid interference with the experimental data.

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In order to investigate the effect of the LW-V system on the indoor thermal environment and comfort during the transition season, objective measurements and subjective questionnaires from the subjects were used in the experiment. The indoor environmental parameters of both rooms were monitored during the comparison experiment, including four parameters: indoor temperature, relative humidity, air speed, and CO₂ concentration. The instruments were all placed on a round table in the center of the room, and the data were recorded through the instruments with the time interval set to 5 min/time.

The experiment was conducted from September 17 to 30, 2023. During the experiment, the time period of 8:30-17:30 was selected according to the office hours. The temperature, relative humidity, air speed, and CO₂ concentration of the indoor environment were measured and analyzed by the four environmental variables that affect human thermal comfort. The questionnaire survey was conducted from 9:00-10:20, 10:40-12:00, 13:00-14:20 and14:40-16:00 between October 5th and October 12th, 2023. Considering the airtightness of the two rooms, both rooms were kept closed during the experimental period to avoid interference with the experimental data.

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Comment 10: They also freely treat the recording of volume concentration units, writing them as PPM or ppm (correct).

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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CO₂ concentration level was an important indicator of indoor air quality, and high CO₂ concentration can affect the occurrence of sick building syndrome, thus affecting people’s health. The LW-V system can absorb CO₂ and release O₂, through the photosynthesis of plants, and play a role in renewing indoor air. Figure 9 compares the indoor CO₂ concentration in the Room A and Room B during the experiment. As shown, the CO₂ concentration in Room A was maintained between 465.09PPM and 555.32PPM with the average CO₂ concentration of 508.81PPM. While CO₂ concentration in Room B was maintained between 455.23PPM and 545.12PPM with the average CO₂ concentration of 494.98PPM. It showed which was 13.83ppm lower than the average CO₂ concentration in Room A. This is because the plants in Room A photosynthesize and absorb CO₂ from the room.

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CO₂ concentration level was an important indicator of indoor air quality, and high CO₂ concentration can affect the occurrence of sick building syndrome, thus affecting people’s health. The LW-V system can absorb CO₂ and release O₂, through the photosynthesis of plants, and play a role in renewing indoor air. Figure 9 compares the indoor CO₂ concentration in the Room A and Room B during the experiment. As shown, the CO₂ concentration in Room A was maintained between 465.09 ppm and 555.32ppm with the average CO₂ concentration of 508.81 ppm. While CO₂ concentration in Room B was maintained between 455.23 ppm and 545.12 ppm with the average CO₂ concentration of 494.98 ppm. It showed which was 13.83ppm lower than the average CO₂ concentration in Room A. This is because the plants in Room A photosynthesize and absorb CO₂ from the room.

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Comment 11: When describing the area of a room m² (the power of 2 should be written as superscript).

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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Vegetables are grown vertically to increase the net photosynthetic rate in a study by Shao et al [19]. And in an office with 1-3 staff and an area of 30m2, 100 plants grown vertically reduced indoor CO₂ concentrations by 25.7-34.3% compared with no planting.

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Vegetables are grown vertically to increase the net photosynthetic rate in a study by Shao et al [19]. And in an office with 1-3 staff and an area of 30m², 100 plants grown vertically reduced indoor CO₂ concentrations by 25.7-34.3% compared with no planting.

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Comment 12: Figure 7 uses the word "Datas" instead of "Data".

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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Figure 6. Meteorological station data during the experimental period

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Figure 6. Meteorological station datas during the experimental period

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Comment 13: The description of the fan used (200D-19DP) includes a note. Unfortunately, without additional explanation, it is incomprehensible to readers.

Response: Thank you for your comment, which is valuable and needed to be illustrated.

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The ST-200D-19DP is a low-noise air supply fan system featuring dimensions of 650mm in length, 470mm in width, and 360 mm in height. It offers dual power settings of 155/120W, air volume of 690/560 m³/h, pressure outputs of 200/190 Pa, and operates at a low noise level of 33/29 dB(A) while requiring 220V voltage.

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Reviewer 4:

Despite the fact than experimental was set up correctly the overall contribution to the selected topic is not adequately described. The major weakness is lack of comparison with some existing systems, for example adiabatic colling. The achieved reduction of CO₂ concentration by 13.83 ppm can be neglected. Since it is with measurement error. It does not describe how plants were watered. Most likely air passing through this wall will absorb soil dust and some possible mold. The PM2.5 wasn’t measured thit in this study. Which is a weakness. Comparison of indoor air freshness sensation voting is too generic. What was the air velocity and mend radiant temperature during this study? These parameters have a strong impact on thermal comfort. Both rooms have a window. So the solar radiation wasn’t constant during the test.

Response: Thank you for your positive evaluation and all your comments on my manuscript, which are extremely helpful in improving the paper quality. According to your comments, we tried our best to make the appropriate revision and all changes were highlighted in the red color for the easy reference in the revised manuscript.

The transition season primarily relies on mechanical ventilation to address indoor comfort, without taking cooling or heating into consideration.

The equipment underwent verification prior to testing, with the error margin being controlled at 2%, equivalent to 5ppm. Based on the questionnaire data, it is evident that there is still a noticeable disparity in CO₂ levels between the two rooms.

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The automatic watering device regulates the soil moisture level between 30% and 50%, ensuring optimal conditions for natural plant growth and room comfort.

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The effectiveness of plants in adsorbing PM2.5 and PM10 is not the primary focus of this study, which is discussed in the section on Research Deficiencies and Prospects.

The study fails to adequately address the issue of dust. Future research will involve more comprehensive questionnaire surveys as well as detailed treatment and analysis of both PM2.5 and PM10.

During the experiment, the measured air speed and radiant temperature intensity were maintained at 0.25-0.55m/s and 26-34℃. The two rooms are identical in all aspects except for the presence or absence of green walls, and no other variables will be present.