Towards Air Quality Protection in an Urban Area—Case Study

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript entitled ”Towards air quality protection in an urban area – case study” is interesting. However, there are several major concerns that authors shall address before could further consider for publication.

1.      Abstract- Authors shall highlight the importance of this paper. The present form seems like a localise case study, which not replicable in other countries. Also, measurable findings shall be provided.

2.      How authors ensure that the simulation result is reliable? Simulation required thorough validation and verification processes to ensure the results are reliable. (Line 245 did mention validation, but I believe the reader don’t get a clear validation idea)

3.      Authors need to highlight the discrepancy of past studies and the gap that authors try to fill in. Current form is not sufficient.

4.      Section 2- methodology- this section does not provide clear approach on how authors conducted the study in a systematic way. I highly recommend authors revise this section according to other related papers published in “atmosphere”.

5.      Results and discussion shall be under section 4. Critical discission is not available. Please compare present findings with past studies. Perhaps can discuss the contradict / consensus findings with past studies.

Comments on the Quality of English Language

Ok.

Author Response

The manuscript entitled ”Towards air quality protection in an urban area – case study” is interesting. However, there are several major concerns that authors shall address before could further consider for publication.

1. Abstract- Authors shall highlight the importance of this paper. The present form seems like a localise case study, which not replicable in other countries. Also, measurable findings shall be provided.

The abstract has been substantially changed. Main measurable findings are added. As to the comment on a localized case study, implementing any forecasting model usually means an application of a general modeling procedure to a particular case study (urban, regional, local, etc.); see the previous publications [7, 34, 35, 36]. The current article follows this approach.

2. How authors ensure that the simulation result is reliable? Simulation required thorough validation and verification processes to ensure the results are reliable. (Line 245 did mention validation, but I believe the reader don’t get a clear validation idea)

The model used has been verified previously and validated on the real emission data [34]. A related explanation is added in the text (lines 229-238).

3. Authors need to highlight the discrepancy of past studies and the gap that authors try to fill in. Current form is not sufficient.

In the study, we aim to assess the potential for improving air quality in the city while comprehensively considering the impact of the dominant emission categories, namely housing and traffic that were not considered earlier. This is specified in the paragraph mentioned above (line 229-238) and also in Section 4.

4. Section 2- methodology- this section does not provide clear approach on how authors conducted the study in a systematic way. I highly recommend authors revise this section according to other related papers published in “atmosphere”.

As mentioned above, using a model always means implementing its general version to a particular case (e.g., a city, a time interval, an emission field, etc.). There are many examples of such applications in the literature, including the references [7, 34-36] concerning the CALPUFF model and Warsaw being a modeled object. In these works, the implementation of the model is thoroughly explained and shown with examples. The present study follows this entire procedure for a more comprehensive representation of emission data, simultaneously covering the impact of the residential sector and traffic. So it seems unnecessary to explain it again.

5. Results and discussion shall be under section 4. Critical discission is not available. Please compare present findings with past studies. Perhaps can discuss the contradict / consensus findings with past studies.

A quantitative comparison of recent results with earlier publications is added in the first paragraph in Section 4 (lines 392-403). The comparison shows that the case considered in this study is more effective in improving air quality in the city than other cases.

Comments on the Quality of English Language

Ok

Reviewer 2 Report

Comments and Suggestions for Authors

The authors aimed to r discusses the current and expected effects of actions taken by the Warsaw authorities, to significantly improve air quality in the city. In order to improve the quality of the article, my suggestions are as follows.

 

1.      The Abstract should be more precise. Include quantitative as well as qualitative results in the abstract. The effectiveness of the current action for the zones.

2.      In the introduction and the first part of the introduction should be aligned with SDG that related to the articles.

3.      Table 1. Comparison of the relative use of energy carriers in households in Poland. It is suggested to include the graph.

4.      In line 139 to 141 the authors mentioned the use of heat pumps and photovoltaic energy has increased significantly. Please add more discussion on these statements.

5.      Figure 2. Change to PM2.5

6.      In line 297 what is (cf. Fig. 2)

7.      It is suggested that the authors add a line graph that compare the effectiveness of LEZ implementation for Table 2 and Table 3.

8.      In summary, include the motivation toward SDG.

9.      Please check the format for references.

 

 

Overall, it is an interesting article. It may be considered after revision.

Comments for author File: Comments.pdf

Author Response

The authors aimed to r discusses the current and expected effects of actions taken by the Warsaw authorities, to significantly improve air quality in the city. In order to improve the quality of the article, my suggestions are as follows.

1. The Abstract should be more precise. Include quantitative as well as qualitative results in the abstract. The effectiveness of the current action for the zones.

Done. The abstract is extended respectively, including SDG aspect.

2. In the introduction and the first part of the introduction should be aligned with SDG that related to the articles.

Added, as above

3. Table 1. Comparison of the relative use of energy carriers in households in Poland. It is suggested to include the graph.

The values in Table 1 are very general estimates. They show, among others, that the use of renewable sources increased by about 200% during the period in question. However, the overall level of their use is still small and will be marginalized on the diagram. In this case, it looks that the tabular form is better for analyzing the changes.

4. In line 139 to 141 the authors mentioned the use of heat pumps and photovoltaic energy has increased significantly. Please add more discussion on these statements.

It follows from Table 1 that the increase is 200% in both cases. This seems to be a clear indication of the change range. See also lines 144-146.

5. Figure 2. Change to PM2.5

Done.

6. In line 297 what is (cf. Fig. 2)

Modified: (compare Fig. 2).

7. It is suggested that the authors add a line graph that compare the effectiveness of LEZ implementation for Table 2 and Table 3.

Although in general the graphic presentation is easier to assimilate, in this case, the tabular form is in our opinion more understandable and more accurate.

8. In summary, include the motivation toward SDG

The relevant comment has been added in the Summary.

9. Please check the format for references.

The format of References is corrected and modified; and one item is added.

Overall, it is an interesting article. It may be considered after revision.

Reviewer 3 Report

Comments and Suggestions for Authors

Line 51.- Please, What type of fuel is used?

Line79 .- How much sulphur is in the fuel?

Line 142.- Are emissions from inland shipping included?

Author Response

Comments and Suggestions for Authors

Line 51.- Please, What type of fuel is used?

As stated in lines 212-216 of the manuscript, the total emission field is composed of three main categories: a) point sources representing industrial and energy sectors (coal, lignite, and renewable sources), (b) line sources of the urban road network (diesel, gasoline fuels), and (c) area sources of the residential sector (all fuels used in the residential sector, see Table 1 for examples)

Line79 .- How much sulphur is in the fuel?

Exactly, per the norms for the fossil fuels used. Particularly, the sulfur content of coal varies widely. The total sulfur is most often in the range of 0.5-5% (coal containing less than 1% sulfur is classified as low-sulfur coal, containing from 1% to 3% sulfur is medium sulfur coal, containing more than 3% sulfur is high sulfur coal).

Line 142.- Are emissions from inland shipping included?

No, because in the case of Warsaw, this share is negligible due to the very low share of inland shipping, compared to the share of emissions from the municipal sector, transportation, and commercial power industry

Reviewer 4 Report

Comments and Suggestions for Authors

The manuscript describes a case-study to improve air quality in Warsaw, Poland. A Clean Air Program has been adopted by local authorities to improve urban air quality in city. Some toxic pollutants such as NOx and PM2.5 have been identified as key compounds to be reduced in the period 2024-2034. Some positive effects are expected by introducting Low-Emission Zones (LEZs) in the city center. Simulations are realized to forecast the urban air quality. The results are very interesting and well-presented. The organization of the manuscript is effective and clear. The paper should be attractive for atmosphere community. Some Minor Revisions are suggested:

- a table of the indicators to characterize the LEZs of the other cited cities should be arranged to appreciate the results and the improvements achieved in the air quality adopted plans.

- other recent references should be added in the bibliography

Comments on the Quality of English Language

Minor editing of English is suggested

Author Response

The manuscript describes a case-study to improve air quality in Warsaw, Poland. A Clean Air Program has been adopted by local authorities to improve urban air quality in city. Some toxic pollutants such as NOx and PM2.5 have been identified as key compounds to be reduced in the period 2024-2034. Some positive effects are expected by introducting Low-Emission Zones (LEZs) in the city center. Simulations are realized to forecast the urban air quality. The results are very interesting and well-presented. The organization of the manuscript is effective and clear. The paper should be attractive for atmosphere community. Some Minor Revisions are suggested:

- a table of the indicators to characterize the LEZs of the other cited cities should be arranged to appreciate the results and the improvements achieved in the air quality adopted plans.

As noted in the paragraph (lines 359-376), numerous publications on the LEZ generally apply to cities of different sizes, which also differ in the zone size and the main indicator by which the effectiveness of the zone can be assessed. In this case, only a general comparison of the method's effectiveness can be done using a chosen indicator (as long as it is included in both cases).

- other recent references should be added in the bibliography

To not increase the volume, only references used directly in the text were included on the list. One item was however added in the revised version.

Comments on the Quality of English Language

Minor editing of English is suggested

English was checked and slightly improved.

Reviewer 5 Report

Comments and Suggestions for Authors

The article is devoted to a very interesting topic and corresponds to the theme of "Atmosphere". The authors have been studying air quality for a long time and are professionals in this field, as evidenced by numerous works.

There are several comments:

1. I would like more justification for the choice of the CALPUFF model and why it is, for example, not BLP or ADMS 5.

2. Perhaps a slightly strange question about the reliability of the data. I understand that you are using official data, but has an assessment been made of how reliable they are?

3. Probably, a separate section on conclusions should be given, where specific quantitative conclusions obtained will be described.

Author Response

The article is devoted to a very interesting topic and corresponds to the theme of "Atmosphere". The authors have been studying air quality for a long time and are professionals in this field, as evidenced by numerous works.

There are several comments:

1. I would like more justification for the choice of the CALPUFF model and why it is, for example, not BLPor ADMS 5.

The main reason is that previous air quality simulations for Warsaw [7, 34, 35, 36] were performed with this model. The idea was to make the results more comparable. Moreover, CALPUFF is a very popular and well-tested model, applied in numerous cases.

2. Perhaps a slightly strange question about the reliability of the data. I understand that you are using official data, but has an assessment been made of how reliable they are?

The emission data used in this work are fully justified by the Chief Inspectorate for Environmental Protection. As far as we know, all available data-gathering methods are used to produce them. However, no estimates of the accuracy of these data are available.

3. Probably, a separate section on conclusions should be given, where specific quantitative conclusions obtained will be described.

In Section 4 a paragraph is added (lines 392-403) where some general quantitative comparison of the overall effectiveness of the approach is discussed and compared with the previous studies.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Generally, the results/ findings are not sufficient. Authors shall include comprehensive results. Also, the methodology section has not yet improved to a satisfactory level (Indexed journal). A clear and comprehensive method enhances the confidence level of results reliability. Authors may refer to the recent publication (by Atmosphere), especially how other authors work on the "method" section. By the way, the topic is worth investigating.

Comments on the Quality of English Language

Satisfactory. Please proofread for the final version.

Author Response

Open Review

(x) I would not like to sign my review report
( ) I would like to sign my review report

Quality of English Language

( ) I am not qualified to assess the quality of English in this paper.
( ) The English is very difficult to understand/incomprehensible.
( ) Extensive editing of English language required.
( ) Moderate editing of English language required.
(x) Minor editing of English language required.
( ) English language fine. No issues detected.

 

	Yes	Can be improved	Must be improved	Not applicable
Does the introduction provide sufficient background and include all relevant references?	( )	(x)	( )	( )
Is the research design appropriate?	( )	(x)	( )	( )
Are the methods adequately described?	( )	( )	(x)	( )
Are the results clearly presented?	( )	( )	(x)	( )
Are the conclusions supported by the results?	(x)	( )	( )	( )

Comments and Suggestions for Authors

Generally, the results/ findings are not sufficient. Authors shall include comprehensive results. Also, the methodology section has not yet improved to a satisfactory level (Indexed journal). A clear and comprehensive method enhances the confidence level of results reliability. Authors may refer to the recent publication (by Atmosphere), especially how other authors work on the "method" section. By the way, the topic is worth investigating.

 

Comments on the Quality of English Language

Satisfactory. Please proofread for the final version.

Submission Date

 

The Authors response

The authors thank the Reviewer for his effort in improving the quality and understandability of our manuscript. However, we find the reviewer's comments rather vague, which makes it difficult to follow their advice. To discuss the confidence and reliability of the results let us notice that they depend on the quality of the emission data and the modeling of the pollutants’ dispersion. Let us start with the latter question.

The authors consider both the problem of implementing the model, its full validation and the data uncertainty in a method different from that suggested by the Reviewer. In the manuscript reviewed, the authors focus mainly on presenting the results obtained from air quality modeling. At the same time, for the simulation method they refer to numerous previous works related to main topics. First of all, as far as the CALPUFF model itself is concerned, being the basic simulation tool in this study, its properties, limitations, and the whole implementation procedure in any specific case study are described in detail in “CALPUFF Version 7-Users Guide” [33]. The model (the current version 7) is widely known and used for modeling the dispersion of atmospheric pollutants at medium spatial scales.

Model implementation. Our numerous previous publications [7, 34-38] (all journals are indexed) deal with examples of how the above model can be applied to analyze the generally poor ambient air quality in Warsaw and to evaluate the effectiveness of various corrective measures. In particular, the paper [35] “Air quality modeling for Warsaw agglomeration” (Archives of Environmental Protection 2017) discusses step-by-step the successive stages of model implementation in the case of the city under consideration (emission data, meteorological data, spatial and temporal resolution, computer simulation). This method of proceeding is then used in subsequent publications while the above implementation details are not repeated (citation of [35] case-study is sufficient) as a reduction of the repetition of earlier works is expected in articles to save space. Moreover, the method is widely known to specialists. 

Model validation. Some of the earlier works, directly referenced in this publication, are related to the model performance assessment and model forecast validation, particularly in the Warsaw case study implementation. The first study (an item added to the References) [34] “An urban scale application and validation of the CALPUFF model” (Atmospheric Pollution. Research, 2016) compares the model predictions with the annual average concentrations of  NOx, PM₁₀, PM_2.5, SO₂, and CO at five major air quality monitoring stations in Warsaw (traffic or background ones). The results confirm the good accuracy of the model forecasts. On the other hand, the paper [35] mentioned above, which also addresses the model validation issue, shows satisfactory values of the FAC2 (Fraction of two) index for the above air pollutants (modeled and measured) at 11 monitoring stations in the city. The results of both these publications provide the required accuracy level of the air pollution forecasts generated by the model. Hence application of the model is fully justified. To make it specific, paragraph 230-245 was added to the manuscript.

Uncertainty analysis. As to the uncertainty of the emission estimates, we used the best available inventory provided by the Chief Inspectorate of Environmental Protection, the official Polish governmental institution that gathers the environmental data. Nevertheless, these data are still uncertain, as all emission inventory data, which causes uncertainty in the simulated results. This subject was discussed in [36] “Emission data uncertainty in urban air quality modeling – case study” (Environmental Modeling & Assessment, 2015). This modeling was done using the Monte Carlo method which was both computer time and space demanding due to thousands necessary computations with the high space resolution of the model. Thus, providing these detailed analysis in the case considered in the manuscript is not justified due to very high computational costs, but the general findings of this analysis are useful in any case.

Simulation results. The mentioned above aspects were taken into account in the implementation of the model discussed in the paper. Full, comprehensive computer simulation results are graphically presented in Section 3, as the annual average pollution concentration maps. Figure 3 compares the concentration maps of two analyzed pollutants for the base year 2018 and a forecast for 2024, resulting from the Clean Air Program implementation. In turn, Figure 5 shows the impact of the gradual introduction of the LEZ in Warsaw on the distribution of NOx annual concentrations in the city, with two-zone sizes considered. Similarly, Figure 6 presents the effect of the gradual implementation of the LEZ on the distribution of PM_2.5 annual concentrations, also taking into account the size of the zone. The remainder of Section 3 presents the simulation results in a quantitative form, as the values of the population exposure to each pollutant discussed, and also resulting from the introduction of previous corrective measures. The results are presented in two tables, Table 2 for the base size of the LEZ and Table 3 for the extended zone version. The results confirm that the zone efficiency significantly increases with its extension.

 

The References list has been respectively amended and formatted.

 

Author Response File: Author Response.pdf