Round 1

Reviewer 1 Report

Major concern

In general, the manuscript is an interesting reading and certainly useful in some way for authorities to check and revise existing odour regulations. However, one of the main drawbacks of the work is that a similar review about worldwide odour regulations has already been published in 2017 in the Journal Chemosphere (Brancher et al., 2017). Naturally, the scientific question arises about the originality of the work. Most of the work covers the same country regulations as Brancher et al. (2017). In other words, the majority of information provided in the manuscript can already be found in Brancher et al. (2017). Moreover, the reader gets the impression that each chapter has been written by the corresponding national expert, and each one did so with his/her own focus presenting information in different ways. For example, it is not clear, why some regulations are outlined extremely detailed (e.g. five pages of the manuscript are dedicated for Japan), while others are kept extremely short (e.g. only a few sentences are dedicated for Quebec). This is the more surprising as according to Brancher et al. (2017) Quebec seems to have several specific and interesting regulations. There is no explanation given in the manuscript on why the authors chose such different levels of information for the different countries/regions. Overall, the manuscript is less structured than the comprehensive and excellent review of Bracher et al. (2017).

Specific comments

• Chapter 2.2: In the section about odour regulations within Germany, the European standard EN 16841 Part 1 is discussed in more detail. As it is a European standard, it should be shifted to chapter 2. I’d also encourage the authors adding a brief discussion about possible conflicts between the EN 16841-1, which is focusing on odour hours, and other national odour regulations, which using OIC based on hourly-mean odour concentrations (e.g. France, Netherlands).
• Chapter 2.3: Apparently, there seems to exist another odour guideline in Austria not mentioned by the authors (see references: Oettl et al., 2019). Furthermore, the authors mention two different methods used in Austria for assessing peak-to-mean concentrations: (i) a variable peak-to-mean model based on stability, and (ii) the German method. However, it seems as there is another method already in use named “concentration-variance” method, which is implemented in the Lagrangian dispersion models GRAL and LASAT (e.g. Brancher et al., 2020; Oettl et al., 2019).
• Chapter 2.7: The authors mention a comprehensive study on dose-response relationships around livestock farms carried out in 2001. Please, quote this study. Is it a completely different one than Noordegraaf et al. (2007)?
• Chapter 2.8: It would be worth mentioning the year when the first Guideline in Lombardy has been issued in the text.
• Lines 548-551: The mentioned evaluation criteria doesn’t seem to make sense as it says that impact maps have to be established for odour concentrations at the 98 percentile (which makes sense), but simultaneously that the dispersion simulation is made for 1, 3 and 5 ou/m³. One cannot fix the odour concentration in the dispersion simulation and at the same time evaluate odour concentrations for a certain percentile. Thresholds in dispersion simulations, such as 1, 3 or 5 ou/m³ are usually used for counting the number of hours within a year exceeding any of this thresholds. The result is then a frequency rather than an odour concentration.
• Lines 659-660: The authors mention studies on dose-response relationships. As such studies are rare it would be very helpful, if these were quoted in the text.
• Table 12: Units are given in ou, while physically correct would be ou/m³. The same holds for the entire chapter 3 except Table 16, where the correct units are given.
• Table 14: Can be removed as both values are already listed in Table 12.
• Line 820: “…comments closed in March 2010”. Please, check the year.
• Line 825: An odour-concentration limit of 70 (ou/m³?) for emissions (discharge) from poultry seems extremely unrealistic. Please, check this figure and add units. Probably, the authors are not talking about odour concentrations but odour emission rates?
• Below Table 21 is an asterisk (*) followed by a note. Where does the asterisk belong to?
• Line 901: Replace “ou” by “ou/m³” or any other unit suitable for describing an odour concentration.
• Table 22: In case “Disorganized” means the same as “Diffusive”, I’d highly recommend replacing it throughout this chapter. Otherwise, a brief explanation should be given about the exact meaning of “Disorganized”.
• While the odour assessment in Shanghai is presented very detailed, the corresponding abstract about the assessment in Hongkong is rather small. I’d recommend limiting Table 21 and Table 22 to say five major chemical substances, and adding some material in chapter 4.2 (e.g. limit/target values applied in Hongkong).
• Chapter 7.7: It is interesting noting that the authors summarize Quebec’s odour regulation in only four sentences, while e.g. Brancher et al. (2017) provide much more information (see main concern).
• Chapter 9: The authors suggest assessing the ‘costs of regulation or no regulation’. What exactly is meant by this, or how can such costs be evaluated in practice?
• Chapter 9: The questions posed by the authors are important of course, but without any answers or suggestions not really helpful for authorities. However, the manuscript could be substantially improved, if the authors would provide ‘best practises’ examples, or a ‘lessons learnt’ section based on their own experiences. For instance, the question on whether an air quality or an emission regulation is preferable in permits has been a matter of discussion in Germany recently, and such discussions would certainly be quite interesting for readers.
• Table 29: For experts involved in the development of odour regulations or concerned with odour assessments the content in Table 29 is largely self-evident. In point 2) Fenceline measurement one reads in the pro column ‘Direct relationship with odour perception by citizens’, while in the con column just the opposite ‘No direct relationship with odour perception by citizens’ is listed.
• Line 1438: Table S1 is not contained in the manuscript.

References

Brancher, M., K.D. Griffiths, D. Franco, H. de Melo Lisboa (2017) A review of odour impact criteria in selected countries around the world. Chemosphere, 168, 1531-1570

Brancher, M., Hieden, A., Baumann-Stanzer, K., Schauberger, Gü., Piringer, M., Performance evaluation of approaches to predict sub-hourly peak odour concentrations, Atmospheric Environment: (2020), doi: https://doi.org/10.1016/j.aeaoa.2020.100076.

Noordegraaf, D.; Bongers, M. Relatie tussen geurimmissie en geurhinder in de intensive veehouderlij (relation between odor immission and odor nuisance for intensive livestock farming). Rapportnummer VROM07A3. PRA Odournet BV (ed). Amsterdam, 2007

Oettl, D., E. Ferrero, H. Moshammer, L. Weitensfelder, M. Kropsch, M. Mandl (2019): Recent developments in odour modelling and assessment in Styria and Salzburg, Austria. 19^th International Conference on Harmonisation within Atmospheric Dispersion Modeling for Regulatory Purposes, June 3 – 6, Bruges, Belgium

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The paper by Anna Bokowa et al entitled “Summary and Evaluation of the Odour Regulations Worldwide” provides a complete overview of the odour regulation in the various countries. The paper indeed provided a comprehensive summary as promised in the title of the document, and the authors did a very good job in this, however the evaluation part as put forward in the title is only very briefly touched upon. I would thus suggest to remove the term evaluation from the title, or a more elaborate evaluation should be provided. Having an overview of methodology is worthwhile although a more extensive discussion could bring the field forward.

Major comments.

1. Authors suggest that “The regulatory approaches outlined throughout this paper provide a foundation for understanding important elements of regulation. “ (line 1383)  However following this statement they provide a series of questions addressing planning, metrics, improvement and recommendations, which do not particularly lead to understand the elements of regulation.
   I would suggest that this part is rephrased to explain the diverse elements which are involved in regulation, and how well these are covered in the approaches in different countries.
2. It is clear that many countries have different approached for different industries involved. It would be of interest to provide justification for these different approaches and also an evaluation of whether odour annoyance is indeed regulated well of circumvented with the approached of regulation in practice.
3. The overview in Table 29 shows that most countries in one or the other way regulate based on exposure levels, which can either be directly measured or modelled. Although this approach is likely a feasible way to regulate odour exposure and indirectly odour annoyance, little interest is given in the current paper that in order to regulate in exposure levels information is needed on exposure response relationships, to quantify a level of exposure which will lead to acceptable odour annoyance. Such is implicit in the current regulations. Authors should discuss this, and should provide information on the availability of this knowledge.
4. Do authors have information on the background of set exposure levels of distance levels in the various countries?
5. Is information available on how well the current legislation protects from annoyance in practice, can this be graded and provide information how to proceed?

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript entitled "Summary and Evaluation of the Odour Regulations Worldwide" is very interesting and topical. However, in this form this paper is too long and in my opinion should be shorter and contain only most important information about worldwide regulations (optionally the paper can be divided into 2-3 parts and each part can contain detailed descriptions). Additionally, I'm not understand the large number of authors involved in the preparation of the work - what is the detailed contribution of prepare each chapter. In my opinion, first of all this paper should be shortened and consider change the structure of presented paper.

Author Response

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Author Response File: Author Response.docx

Reviewer 4 Report

This substantial manuscript presents a comprehensive and impressive review of global odour regulations by a large group of authors.  Although it is generally well written, I think that it requires one of the authors (preferably a native English speaker) proof the entire manuscript to ensure consistent structure, style, punctuation and spelling (UK vs US English) throughout.  Below I list concerns and suggestions.

• Structure:
  • It is a long article. A table of contents would improve the navigation within the article significantly.  Currently it is hard to navigate.
  • Within regional and country sections (2-8), better aligning the subheading structure across country subsections would be contribute to greater unity of the article. Removal of sections at less than the country level could be a simple solution.
• Style:
  • Writing style varies by section. This needs to be addressed so that the article reads smoothly.
  • Some sections use bullet points/numbers frequently (e,g. USA, Sec. 6 – seems unnecessary for lines 1028-1037) and some not at all (e.g. Australia and New Zealand, Sec. 3. A middle ground between these two would be best and should help clarify some issues described subsequently.
• Punctuation/Spelling:
  • The article begins with UK English, but around page 23 it turns to US English, and then back again later. It is essential that one option be chose and it be maintained throughout.  Odour or odor?  Grey or gray?  , etc.
  • There are a couple of portions of the manuscript that are hard to understand due to the punctuation and would benefit from rewriting and applying numbers/bullet points:
    • Lines 129 to 139 is extremely confusing – especially the seeming outlier point 6 (line 139). The list does not strictly seem to be policies, rather approaches taken in the various policies.
    • Lines 712 to 735 of section 3 (Australia and New Zealand).
  • For chemical names of sulfur-containing species, IUPAC spelling should be used. Contrary to Microsoft Word’s spell checker, sulphur/sulphate/sulphide are not correct.  They should all use “f” for the “ph” whether the selected language is UK or US English.
• Terminology:
  • There are many acronyms. A glossary should be considered.
  • Please use consistent terminology throughout the paper: e.g. pig or swine (not both)?

Some miscellaneous comments:

• Line 228 – the reference (19) does not go by this name so capitalisation seems inappropriate usage. Also, “emission” not “immission”?
• Line 372 should read DEFRA.
• Why the hyperlinks in lines 444 to 452?
• Why the urls in lines 499 and 503 rather than a citation?
• Line 530 should read “…is being reviewed…”
• Table 12 (page 19) needs significant work with formatting to avoid words breaking inappropriately across lines.
• Table 13 and 14:
  • Table 13: are lines 743 to 748 footnotes?
  • Table 14: are lines 750-751 a footnote?

Both read ambiguously, but seem like they may be footnotes.  If they are not, I suggest moving lines 743 to 748 after Table 14 since Tables 12-14 are all cited in the para preceding Table 12.

• Line 969: Reword the start of the sentence “The odour index of wastewater…”
• Line 1194: The dash is unnecessary.
• Line 1226: final clause needs improving.
• Line 1232: complaints.
• Table 29 lacks capitalisation in heading.
• It would be interesting to have a comment from the authors – perhaps in the discussion or conclusion – on this recent PhD dissertation from the University of California at Los Angeles (not cited): Braithwaite, S.K. Sensory Analysis and Health Risk Assessment of Environmental Odors. Ph.D. Thesis, University of California-Los Angeles, Los Angeles, CA, USA, 2019. It also makes quite a wide, critical survey of sensory methods, and – of most relevance here – suggests application of the odour profile method as a superior sensory method to dilution olfactometry.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

All comments have been answered by the authors. Corresponding changes in the manuscript are satisfactory.

Author Response

We are thankful for the feedback and the opportunity to strengthen the manuscript.

Reviewer 2 Report

Authors have replied to my questions and addressed these mainly by changing the title of the manuscript as requested.

Minor: authors have added additional literature. The literature reference of [77] is not correct, and should be adapted.

77. Geelen L.; Boers D.; Brunekreef B.; Wouters I.M. Results of new investigations on odour nuisance around livestock farms in 1965
the regions of Brabant and Limburg-north. Public Health Service GGD of Brabant and the Institute for Risk Assessment Sciences IRAS Utrecht, 2015.

this report should be referred to as:

Geelen L.; Boers D.; Brunekreef B.; Wouters I.M."Geurhinder van veehouderij nader onderzocht: meer hinder dan Handreiking Wgv doet vermoeden? - Actualisatie blootstellingresponsrelatie tussen gemodelleerde cumulatieve geurbelasting en geurhinder in Noord-Brabant en Limburg-Noord." Odor nuisance from livestock farming further studied: more nuisance than the Wgv Guide suggests? - Update of exposure-response relationship between modeled cumulative odor exposure and odor nuisance in Noord-Brabant and Limburg-Noord. Public Health Services (GGD) of Brabant and the Institute for Risk Assessment Sciences (IRAS) Utrecht, 2015.  Available via:http://www.academischewerkplaatsmmk.nl/ufc/file2/hgm_internet_sites/graskl/fb5d0198ad97606c2afcff6d278343b8/pu/Eindrapport_GEUR_Loes_Geelen_23_3_2015.pdf

This research is also available in a peer-reviewed paper, which should be added: 

Boers D, Geelen L, Erbrink H, Smit LAM, Heederik
D, Hooiveld M, Yzermans CJ, Huijbregts M, Wouters IM,
2016. The relation between modeled odor exposure from
livestock farming and odor annoyance among neighboring residents. Int Arch Occup Environ Health 89: 521-530. https://doi.org/10.1007/s00420-015-1092-4

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

I accept the paper in present form

Author Response

We are thankful for the opportunity to address the comments and strengthen the manuscript in Round 1. We made additional minor improvements in Round 2.