Exposure to PM₄ in Homes with Tobacco Smoke in and around Katowice, Poland

Round 1

Reviewer 1 Report

This paper presents a study on the exposure to PM4 in Homes with Tobacco Smoke in and around Katowice, Poland. Although as the authors mentioned, it shall be the first study about PM4 in homes in Poland, it has a large space to improve: 
(1) We all know PM2.5 is more dangerous than PM4. Why did not the authors do the test on both PM2.5 and PM4? 

(2) The paper looks more like a measurement report. We can find very few analysis of the sources of PM4, numbers of tobacco smokers in each home and the PM4 concentration, etc. 

(3) If the paper only draws one main conclusion - the PM4 in the home with smokers is much higher than that in homes without smokers, which is obviously a matter of fact, it is far from enough. As an original research paper, it shall try to dig further to obtain profound findings. 

Author Response

Reply to the Reviewer 1:

First of all, we would like to express our appreciation for the opinion and comments of the reviewer.

Below is our answer to each review point.

1. We all know PM2.5 is more dangerous than PM4. Why did not authors do the test on both PM2.5 and PM4?

Reply: The belief that PM2.5 is more dangerous than PM4 (or, for example, PM10) is a fairly common misconception. The dust fractions are defined such that the larger fraction contains the finer fraction, e.g., PM4 contains PM2.5 and PM10 contains PM4 and PM2.5. The toxic or carcinogenic effect of airborne particles is determined by the absorbed dose of dust that remains in the body. For this reason, the PM2.5 fraction may be more easily associated with health effects as particles with an aerodynamic diameter less than 2.5 µm are deposited in the lower respiratory tract and are not re-emitted from there (what means that the all entire inhaled dose remains in the body). However, this does not mean that, for example, the PM10 fraction is less hazardous, as it also contains fine dust. The thing is that it also contains a large part of the mass of particles with a diameter of 7 to 10 µm, which settle in the head and from which a significant amount is re-emitted as a result of exhaling, coughing, etc. Therefore, the dose of coarse dust particles remaining in the body is only a small fraction of absorbed dose. For this reason, coarse particles are considered less hazardous to health than fine particles.

In the case of the PM4 fraction we are dealing with the PM2.5 fraction and particles with a diameter of 2.5-4.0 µm. Absorbed particles of this size are only slightly re-emitted from the body, so they can also be hazardous to human health. Their role in the intoxication process of the organism is still relatively poorly understood, so studies of exposure to PM4 seem to be currently more interesting than studies of exposure to PM2.5.

As a result of this comment of the Reviewer 1, we came to the conclusion that the reader should be able to confront our decision to test exposure to PM₄ with the current knowledge about the health effects of exposure to dust fractions greater than PM2.5 and we added the item:

Adar S.A., Filigrana P.A., Clements N., Peel J.L. (2014) Ambient coarse particulate matter and human health: A systematic review and meta-analysis. Curr. Envir. Health Rpt. 1,258–274 DOI 10.1007/s40572-014-0022-z

2. The paper looks more like a measurement report. We can find very few analysis of the sources of PM4, number of tobacco smokers in each home and the PM4 concentration, etc.

Reply:   Tables 1-3 present the average level of PM4 in the studied group of homes. Additional data, such as the maximum and minimum concentration of these airborne particles, standard deviation and the number of homes tested are also included. Detailed information describing each surveyed home would be sent to readers if needed.

3. If the paper only draws one main conclusion – the PM4 in the home with smokers is much higher than in homes without smokers, which is obviously a matter of fact, it is far from enough. As an original research paper, it shall try to dig further to obtain profound findings.

Reply: Reviewer 1's opinion is too harsh. While we haven't done any groundbreaking research, we believe we've got some interesting and valuable results. As you can read in the Conclusions, we have shown that:

1. a) In Poland infiltration of airborne particles from outdoor into indoor air is very similar to the results obtained in different European countries. On the other hand, the contribution of indoor emission sources (excluding tobacco smoking) in Polish homes to the total concentration of respirable particles indoors was elevated comparing to other European homes.
2. b) We not only showed that the concentration of PM₄ in homes with ETS is higher than in buildings with non-smokers, but we also estimated the daily dose of PM4 inhaled by children in different groups of apartments. These are the first such results obtained in Poland.
3. c) Using X-ray photoelectron spectroscopy, we have documented that the surface layer of PM4 particles from ETS homes contains relatively much more carbon and less oxygen than airborne particles collected in non-smoking homes. To our knowledge, this XPS study to determine the surface chemical composition of particles under the influence of ETS is the first in the world.

Author Response File: Author Response.pdf

Reviewer 2 Report

The article deals with exposure of the airborne particles less than 4 μm (PM4) in homes with tobacco smoke in and around Katowice, Poland. The introductory part of the article is a search of publications that deal with similar issues in other European regions. Selected research sites are documented in Figure 1. The measuring technique used was adequate to the aims of the study, which involved 118 respondents from different age and professional categories. The measurement results are documented in tabular and graphical form. At the end of the article, the results of the study are briefly summarized and commented.
At the end of the article, the results of the study are briefly summarized and commented. As this is a publication in a scientific journal, the text of the article should in some way go beyond a mere measurement protocol, even if qualified. I therefore recommend supplementing the conclusions in particular by proposing possible recommendations that could contribute to improving the situation in the region, although it is understandable that their implementation exceeds the real possibilities of the authors of this study.

Author Response

Replay to the Reviewer 2:

First of all, we would like to express our appreciation for the opinion and comments of the reviewer.

Below is our answer his/her comment.

As this is a publication in a scientific journal, the text of the article should in some way go beyond a mere measurement protocol, even if qualified. I therefore recommend supplementing the conclusions in particular by proposing possible recommendations that could contribute to improving the situation in the region, although it is understandable that their implementation exceeds the real possibilities of the authors of this study.

Replay: Following the Reviewer's advice, we have added a short Recommendation to the Conclusions:

“In the course of our research, we found that in Poland, the exposure of non-smokers, especially children and teenagers to tobacco smoke in their homes, is still very serious and  does not seem to be improving any time soon. To change this, it would be necessary to conduct a broad and multi-faceted campaign to make parents aware of the problem of the ETS. Our observations show that although awareness of the risk of smoking in Polish families is currently quite high (but smokers are consciously ready to take the risk), the importance of ETS is often underestimated.”

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper presents a dataset for the indoor and outdoor concentrations of PM4 (particulate matter with aerodynamic diameter up to 4 μm) in three locations in Upper Silesia, Poland. Observations are made on the trends in indoor and outdoor air qualities, and some investigations were made on the dosage of inhaled aerosols, and also the chemical composition of the surface of the pollutant matter. The paper presents some interesting results, but some issues should be addressed:

1. The definition of PM4 in the abstract is imcomplete: what parameter of the particles is less than 4 μm?
2. Some sources should be given for certain claims made in the paper:
   (Line 70) 'This region (Upper Silesia) is considered the most industrialized and polluted region in the world.'
   (Line 113) '... in the single-family houses in this region where approximately one pack of cigarettes is smoked per day.'
   (Line 124) 'However, particles... with a diameter of 3 to 4 μm (even up to 5 μm) can also cause serious adverse health effects.'
3. (Lines 73-75) The meaning of 'The problem of... 1960s and 1970s' is unclear.
4. The dark red colour used to annotate Figure 1 is difficult to make out from the map.
5. Can images of the samplers be provided to show what the measurement setup looks like?
6. In line 165-166, it is stated that there are no other sources of air pollutant emissions in the selected houses. Yet, during the analysis later in lines 333-335, various sources are given. Please clarify this.
7. Please fix the alignments of each cell in Tables 1-3, and also of equations (3)-(4) and the succeeding text. Also, what does SD mean?
8. Where are the corresponding figures for other European homes, which are required for the comparison in line 329-331 to be made?
9. Figures 3-6 are also very blur. Are higher resolution mages available?

There are also numerous typos and extra spaces present throughout the manuscript. Some more noticeable errors include:

'Correspondence' being repeated in the author details
'XXI century' should be 'twenty-first century'
'per saldo'

Author Response

Replay to the Reviewer 3:

First of all, we would like to express our appreciation for the opinion and comments of the reviewer.

Below is our answer to each review point.

General comment: Reviewer 3 indicated that the introduction and the result presentation must be improved

Replay: We added in the “Introduction” (page 2, line 52) the following sentence:

“It should be noted that although the global prevalence of daily smoking has decreased (Ng et al., 2014), the absolute number of smokers has increased to almost one billion people in 2012 (Beaglehole et al., 2015). About 6 trillion cigarettes were smoked worldwide in 2016 (World-Lung-Foundation,2015)”.

Ng, M., Freeman, M.K., Fleming, T.D., Robinson, M., Dwyer-Lindgren, L., Thomson, B., Wollum, A., Sanman, E., Wulf, S., Lopez, A.D., Murray, C.J.L., Gakidou, E. (2014) Smoking prevalence and cigarette consumption in 187 countries, 1980–2012. JAMA 311, 183.

 https://doi.org/10.1001/jama.2013.284692.

Beaglehole, R., Bonita, R., Yach, D., Mackay, J., Reddy, K.S. (2015) A tobacco-free world: a call to action to phase out the sale of tobacco products by 2040. Lancet 385, 1011–1018.

https://doi.org/10.1016/S0140-6736(15)60133-7.

World-Lung-Foundation (2015) The Tobacco Atlas: Consumption [WWW Document].

At the end of the “Results and Discussion” section (page 15, line 495) we have included the following sentence:

“Our study indicates that advanced monitoring of people exposed to tobacco smoke should be continued.  However, in future studies of exposure, it would be important to utilize markers for PM, such as nicotelline, as well as gas-phase markers such as nicotine. Both phases contain numerous toxic substances and of particular concern in the particle phase are the highly carcinogenic tobacco specific nitrosamines (Aquilina et al., 2021).”

Aquilina N.J., Havel Ch.M., Cheung P., Harrison R.M., Ho K.-F., Benowitz N.L., Jacob III P. (2021) Ubiquitous atmospheric contamination by tobacco smoke: Nicotine and a new marker for tobacco smoke-derived particulate matter, nicotelline. Environment International 150, 106417.

https://doi.org/10.1016/j.envint.2021.106417

1. The definition of PM₄ is the abstract is incomplete: what parameter of the particles is less than 4 µm?

Replay: This piece of text has been corrected. Currently reads: “(airborne particles with an aerodynamic diameter less than 4 µm)”

2. Some sources should be given for certain claims made in the paper:

(Line 70): „This Region (Upper Silesia) is considered the most industrialized and polluted region in the world”  In fact this sentence is little different (“This region belongs to the most industrialized and polluted region in the world”) and now it has been changed “This region belongs to the most industrialized and polluted region in Europe“. The following citations are included:

http://powietrze.gios.gov.pl/pjp/airPollution?woj=slaskie (Forecasts of air pollution in the Silesian Voivodeship, Katowice, Poland, 2021)

Annual Air Quality Assessment in the Silesian Region /Voivodeship. Regional report for 2020 (in Polish: „Roczna Ocena Jakości Powietrza w Województwie Śląskim. Raport wojewódzki za rok 2020”. Regionalny Wydział Monitoringu Środowiska w Katowicach. Katowice, Poland , 2021.

(Line 113): „…in the single-family houses in this region where approximately one pack of cigarettes is smoked per day”

The following sentence has been added: “The houses for the research were selected on the basis of a previously conducted survey in which the respondents answered whether they smoke cigarettes and how many cigarettes they smoke per day”.

(Line 124): “However particles… with a diameter of 3 to 4 µm (even up to 5 µm) can also cause serious adverse health effects”

This sentence has been slightly changed: “However particles… with a diameter of 3 to 4 µm can also cause serious adverse health effects” and the following citation is included:

Adar S.A., Filigrana P.A., Clements N., Peel J.L. (2014) Ambient coarse particulate matter and human health: A systematic review and meta-analysis. Curr. Envir. Health Rpt. 1,258–274 DOI 10.1007/s40572-014-0022-z

3. (Lines 73-75) The meaning of “The problem of …1960 and 1970 “ is unclear.

Replay: This part of the text has been changed:

“The problem of environmental pollution in this area was recognized as serious already in the late 1950s, but this did not stop further environmental degradation. The greatest intensity of this process, including the greatest air pollution, took place in the 1960s and 1970s.”

4. The dark red colour used to annotate Figure 1 is difficult to make out from the map.

Replay: We will try to improve this Figure.

5. Can images of the samples be provided to show what the measurement setup looks like?

Replay: Figures 3-6 show photos of several samples (filters with collected PM₄ particles).

6. In line 165-166 it is stated that there are no other sources of air pollutant emissions in the selected houses. Yet, during the analysis later in lines 333-335 various sources are given. Please clarify this.

Replay: The state (line 165-166) has been little changed: “In all selected single-family houses, there were no sources of air pollution other than tobacco smoking and stoves. All homes, including flats, may also occasionally have re-emissions of settled dust generated by the movement of residents”.

7. Please fix the alignments of each cell in Tables 1-3, and also of equations (3)-(4) and the succeeding text. Also, what does SD mean?

Replay: It will be done. These problems appeared in the Editorial Office. SD means "standard deviation". This information will be added to the Tables.

8. Where are the corresponding figures for other European homes, which are required for the comparison in line 329-331 to be made?

Replay: This statement (line 329-331): “Anyway it can be concluded that the contribution of indoor emission sources in Polish homes to the total concentration indoors is elevated comparing to other European homes” is the conclusion from the analysis of Figure 2. Based on this figure, it can be roughly assume that the background concentration PM4 (i.e. C_INDOOR value for C_OUTDOOR = 0) ẞ = 23 µg m-3, while the value of ẞ estimated by Hoek et al. for European houses is only 5.75 µg m-3. This conclusion remains true even considering that Hoek et at obtained this value for PM_2.5 and not for PM₄. Please note that this explanation is presented several lines earlier (line 320-328).

9. Figures 3-6 are also very blur. Are higher resolution mages available?

Replay: We will try to improve it, but it is not easy.

10. There are also numerous typos and extra species present throughout the manuscript. Some more noticeable errors include:

“Corresponding being repeated in the author details “XXI century” should be “twenty-first century”  “per saldo”

Replay: At now it is written: “twenty-first century”.  Besides, linguistic proofreading will be carried out by a professional company.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Most of my comments have been satisfactorily addressed. Some issues however remain:

1. The dark red annotations in Figure 1 are still difficult to read - if possible, change all annotations to be yellow instead.
2. Regarding Comment 5, I asked for photos of the samplers (not the samples!), preferably as they were used at the measurement sites.

Author Response

Reply to Reviewer 3

Comments and Suggestions for Authors

Most of my comments have been satisfactorily addressed. Some issues however remain:

Reply:

We appreciate the work of the Reviewer. Thank you

Remark

The dark red annotations in Figure 1 are still difficult to read - if possible, change all annotations to be yellow instead.

Reply:

While we agree that the quality of Figure 1 could be improved, unfortunately we are unable to do so. Perhaps the Editorial Board could help us in this matter.

Remark

Regarding Comment 5, I asked for photos of the samplers (not the samples!), preferably as they were used at the measurement sites.

Reply:

I'm sorry for my mistake. An additional drawing (photograph) of the SKC sampler used in our study is now included in the revised manuscript (in page 5, lines 171-177). In this page 5 (line 166) it is written:  “Airborne particles were collected using SKC samplers (USA) with cyclones with a cut-off diameter of 4.0 µm (see Figure 2)”.

 Unfortunately, we did not take photos to fully document our measurements. On the other hand, no reviewer has ever requested such photographs, even though I have co-authored a large number of articles in my life.

Again, thank you for all comments and remarks.

Author Response File: Author Response.pdf