Particulate Matter Concentrations and Fungal Aerosol in Horse Stables as Potential Causal Agents in Recurrent Airway Disease in Horses and Human Asthma and Allergies

Round 1

Reviewer 1 Report

Comments on “Particulate matter concentrations and fungal aerosol in horse stables as potential causal agents in respiratory system diseases and allergies”

 

Authors reported pollution characteristics in two horse stables in Poland.

One of my major concerns is that the authors used a low-cost sensor to measure the mass concentrations of PM size fractions, and the low-cost sensor data requires correction. No details were provided on this aspect.

Next, the authors summed up the PM10, PM2.5, and PM1 to estimate the total PM, this is not correct as PM1 and PM2.5 are subsets of PM10.  This might have altered their whole results and arguments.

The filter sample size and the PM data logging details need to be provided. I believe the PM sensor is a real-time instrument, and the sampling strategy needs to be presented. More details on the study period, whether these measurements are simultaneous across the stables are not, should be provided.

Line 113: cubic meter not square meter

Table 1: What is the respirable dust concentration?

Line 202: ‘fine fractions’ is not clear

Line 273: positive correlation between PM10 and RH is due to hygroscopic growth, this sensitivity of the data needs to be corrected

The discussion part is too lengthy.  Authors are suggested to precise it and limit to the context. A few sentences are too long, and need to be split into 2 or 3 sentences.

Author Response

Reviewer 1

We would like to thank for the helpful suggestions made by the Reviewer. Below you can find point-by-point response to the remarks.

One of my major concerns is that the authors used a low-cost sensor to measure the mass concentrations of PM size fractions, and the low-cost sensor data requires correction. No details were provided on this aspect.

Response: As we stated in the corrected Materials and Methods section, all LOOKO2 devices are calibrated before deployment. The manufacturer of the devices has introduced a system preventing the incorrect data on the air condition from being sent to the network. All devices are calibrated before deployment. After installation and configuration, the device is being connected to the LOOKO2 server. The data are being analyzed, calibrated, and only then presented to the user. However, we also decided to include a few sentences in the Discussion section referring to the popularity of low-cost sensors, their convenience, but at the same time their potential low accuracy due to a number of environmental parameters that affect their estimations. We emphasized that the data obtained using these sensors should be treated with caution and compared to the ones obtained using the same technology. We also showed that the use of low-cost sensors in assessing indoor air quality has been tested in other studies and is generally recommended due to unavailability of reference monitor stations for this purpose.

Next, the authors summed up the PM10, PM2.5, and PM1 to estimate the total PM, this is not correct as PM1 and PM2.5 are subsets of PM10.  This might have altered their whole results and arguments.

Response: we corrected this error and decided to present the inhalable PM values in places where the incorrect total PM values were presented. Therefore, generally, the sections of Results and Discussion needed to be changed only in some places and to a minor extent rather than altering the entire outcome of the study.

The filter sample size and the PM data logging details need to be provided. I believe the PM sensor is a real-time instrument, and the sampling strategy needs to be presented. More details on the study period, whether these measurements are simultaneous across the stables are not, should be provided.

Response: more details were provided in the Material and Methods section referring to the particulate matter measurements.

Line 113: cubic meter not square meter

Response: corrected

Table 1: What is the respirable dust concentration?

Response: The concentration of respirable dust is provided below the Total dust and above the temperature values in Table 1

Line 202: ‘fine fractions’ is not clear

Response: this was specified in brackets.

Line 273: positive correlation between PM10 and RH is due to hygroscopic growth, this sensitivity of the data needs to be corrected

Response: based on a number of studies that we have examined when trying to find a solution to this remark, we found that the so far published studies concerning the hygroscopic growth correction are based on large number of variables and specific information that needs to be taken into account when assessing whether the hygroscopic growth actually did happen, e.g. chemical composition of PM that may significantly affect the hygroscopic properties of particles (Sicard et al. 2022). This is also supported by Won et al. (Scientific Reports, 2021), who also states that precise determination of PM hygroscopic growth is a challenging and complicated task, due to the complex interactions of PM with various meteorological and environmental parameters. Molnar et al. (2020) suggested a reliable aerosol hygroscopicity correction method based on the visibility data (in kilometers). However, such far reaching measures are far beyond the scope of this study. As stated in the corrected Material and Methods section, the manufacturer of the Looko2 device has introduced a system that detects malfunctioning of smog sensors, which prevents incorrect data on the air condition from being sent to the network. Therefore, in our opinion the data and their interrelationships, which were obtained in the course of our study, can be considered as reliable. Also, the fact that the measurements were conducted indoors and in all cases with the same device, makes the comparison of the data between two stables reliable. Moreover, the positive correlation between RH and PM10 was observed only in the case of the Kraków stable, while in the Tarnów stable it was not observed (Spearman’s correlation coefficient -0.484 in Tarnów, 0.786 in Kraków). The RH ranges were similar in both stables (55-70% in Kraków, 53-72 in Tarnów), while the PM10 ranges were much more diverse in Tarnów (10-19 indoors in Kraków; 54-109 in Tarnów). Having this in mind, we find that this remark cannot be applied to our observations.

The discussion part is too lengthy.  Authors are suggested to precise it and limit to the context. A few sentences are too long, and need to be split into 2 or 3 sentences.

The Discussion section was shortened. Some long sentences were divided into shorter ones. The first paragraph of the Discussion has been moved to the final section of the Introduction, to put more focus on the health-related issues of the study, as suggested by the Reviewer 2.

Reviewer 2 Report

The present manuscript describes an original study concerning the presence of particulate matter in air from stable. The study focuses on bio-particle of fungal origin, that are involved on respiratory diseases of horses.

The design and experimental protocols are adequate, and results are presented in very clear manner. Thus, the article is suitable for publication.

Small typing and grammar errors should be corrected prior to publication.

Line 113> cubic meters not square meters

Figures 4 and 5> the species names should be italicized

Line 294? May not mey

Author Response

Reviewer 2

We would like to thank the Reviewer for the helpful suggestions. Below you can find the point-by-point responses to the remarks.

The importance of the fungal diversity found in this paper should be related to the diseases associated with humans and/or horses in the relevant paragraphs.

Response: the Results section has been divided into specific paragraphs, while the importance of our entire observations (PM levels, culture-based fungal aerosol concentrations and NGS-based fungal species composition) was referred to the human or horse diseases in the Discussion section, which is designed to be a single and possibly concise paragraph. Therefore, we would like not to divide this section into subsections, as this would make this chapter even longer than it is now.

The title of the article should be more specific and mention human and animal diseases.

Response: The title was changed to: Particulate matter concentrations and fungal aerosol in horse stables as potential causal agents in recurrent airway disease in horses and human asthma and allergies

Specific Comments:

At the end of the introduction, you should be more specific about the relevance of the research to the animal or human approach.

Response: We changed the end of the Introduction section to make it more specific about the health threat issues, as suggested. We also moved a short paragraph from the beginning of the Discussion section to the end of the Introduction as this fits more this specific section of the paper.

In the Materials and Methods section, double check if you are referring to duplicates as specified in line 114 or triplicates as mentioned in the headings of tables 2 and 3.

Response: This was corrected

In Section 2.1 (Materials and Methods) you should mention the screening points (time of the day) and specify which letter represents each of the former.

Response: this was corrected.

It is not appropriate at this point to refer the reader to the results section (Table 1).

Response: We deleted the reference to Table 1 and listed all times of day when the experiment was performed.

Since the results start with particulate matter and microclimatic parameters, you should reorder sections 2.2 and 2.3.

Response: Corrected

It is recommended to express the fungal bioaerosol concentration data using exponents as shown in the discussion section and perhaps also in the figures.

Response: the data in table were presented using exponents as suggested and the figures were also corrected.

Indicate the names of the axes of figures 2 and 3 even though it is specified at the bottom of the figure.

Response: this was corrected

In figures 4 and 5, the names of the species and genera must appear in italics.

Response: this was corrected

In table 3, PM1 is mentioned twice and misses PM10.

Response: this was corrected

Reviewer 3 Report

The importance of the fungal diversity found in this paper should be related to the diseases associated with humans and/or horses in the relevant paragraphs.

The title of the article should be more specific and mention human and animal diseases.

Specific Comments:

At the end of the introduction, you should be more specific about the relevance of the research to the animal or human approach.

In the Materials and Methods section, double check if you are referring to duplicates as specified in line 114 or triplicates as mentioned in the headings of tables 2 and 3.

In Section 2.1 (Materials and Methods) you should mention the screening points (time of the day) and specify which letter represents each of the former.  It is not appropriate at this point to refer the reader to the results section (Table 1).

Since the results start with particulate matter and microclimatic parameters, you should reorder sections 2.2 and 2.3.

It is recommended to express the fungal bioaerosol concentration data using exponents as shown in the discussion section and perhaps also in the figures.

Indicate the names of the axes of figures 2 and 3 even though it is specified at the bottom of the figure.

In figures 4 and 5, the names of the species and genera must appear in italics.

In table 3, PM1 is mentioned twice and misses PM10.

Author Response

Reviewer 3

We would like to thank the Reviewer for the helpful suggestions. Below you can find point-by-point response to the remarks.

The importance of the fungal diversity found in this paper should be related to the diseases associated with humans and/or horses in the relevant paragraphs.

Response: the Results section has been divided into specific paragraphs, while the importance of our entire observations (PM levels, culture-based fungal aerosol concentrations and NGS-based fungal species composition) was referred to the human or horse diseases in the Discussion section, which is designed to be a single and possibly concise paragraph. Therefore, we would like not to divide this section into subsections, as this would make this chapter even longer than it is now.

The title of the article should be more specific and mention human and animal diseases.

Response: The title was changed to: Particulate matter concentrations and fungal aerosol in horse stables as potential causal agents in recurrent airway disease in horses and human asthma and allergies

Specific Comments:

At the end of the introduction, you should be more specific about the relevance of the research to the animal or human approach.

Response: We changed the end of the Introduction section to make it more specific about the health threat issues, as suggested. We also moved a short paragraph from the beginning of the Discussion section to the end of the Introduction as this fits more this specific section of the paper.

In the Materials and Methods section, double check if you are referring to duplicates as specified in line 114 or triplicates as mentioned in the headings of tables 2 and 3.

Response: This was corrected

In Section 2.1 (Materials and Methods) you should mention the screening points (time of the day) and specify which letter represents each of the former.

Response: this was corrected.

It is not appropriate at this point to refer the reader to the results section (Table 1).

Response: We deleted the reference to Table 1 and listed all times of day when the experiment was performed.

Since the results start with particulate matter and microclimatic parameters, you should reorder sections 2.2 and 2.3.

Response: Corrected

It is recommended to express the fungal bioaerosol concentration data using exponents as shown in the discussion section and perhaps also in the figures.

Response: the data in table were presented using exponents as suggested and the figures were also corrected.

Indicate the names of the axes of figures 2 and 3 even though it is specified at the bottom of the figure.

Response: this was corrected

In figures 4 and 5, the names of the species and genera must appear in italics.

Response: this was corrected

In table 3, PM1 is mentioned twice and misses PM10.

Response: this was corrected

Reviewer 4 Report

The paper contributes for the specifical field to horses heatly. It was very important to see that the fungi can penetrate deeply into the respiratory system.   This paper can help with a lot of research on horses. The methodology was very good and recents references. Congratulations.

Author Response

Thank you for the positive comments on our paper. In order to improve it even more, we included the changes as suggested by the Reviewers 1, 2 and 3.