Effects of Creating Street Greenery in Urban Pedestrian Roads on Microclimates and Particulate Matter Concentrations
Round 1
Reviewer 1 Report
Authors provided a statistically interesting case study based on a theoretical model to check the impact of street greenery on temperature and particulate matter concentrations.
The paper contributes to research on actually important issues and is a theoretical study which results could be implemented in practical programs of improving climate conditions in cities. Authors state at the end of section 5 that their conclusions are similar to (L 299) the findings of previous studies, so we do not have any groundbreaking theories, but another confirmation of observations from previous studies. Nonetheless, conclusions speak for themselves and are sound and well grounded in research outcomes and also clearly presented in figures.
However, the paper is messy and written in a manner that it looks in some parts as a draft and it definitely needs rewriting.
Also in the conclusion no further research directions are mentioned and no suggested solution to the problem is mentioned (Authors suggest that measures to improve air quality should be introduced - but do not state what type of them...)
Authors already carried out similar simulation - but examined different factors (Floor Area Ratio Change) - Analysis of the Effects of Floor Area Ratio Change in Urban Street Canyons on Microclimate and Particulate Matter and this paper is written as a consitent text, while the current paper has reliable data but needs polishing.
Below detailed remarks:
In the introduction Authors use repetitively word pollutants and air pollution - can you find any synonyms? - in some cases word exhaust fumes would be appropriate (athough not everywhere, because not only exhaust fumes contribute to incerased levels of PM 10 and PM 2.5 and other substances that you measure in your study).
L37 - not only dense buildings, but also impermeable surfaces in general and many other factors contribute to UHIs. it would be suitable to mention them here just briefly.
LL 57 - 60: " Creating walking environments where people want to walk has not been very successful, however, because the factors that control particulate matter along roadsides are poorly understood, and because approaches to control this dust are lacking [6]." You refer here to guidelines and a document from the year 2000 (it is 22 years old) do you think that for the last more 20 years the particulate matter concentration was the main reason why people do not walk in Seoul? Do you have any research on these assumptions? Of course, bad air quality is something that affects pedestrians, but this probably is not the sole problem.
Definition of urban canyon can be provided earlier than in LL 61-65.
In the introduction LL 66 - 74 are part of the model file of the paper provided by MDPI - pleqase erase them.
Generally paragraphs of the introduction could be linked better.
Section on prior research focuses mostly on literature on greenery and pollution in pedestrian areas (references from 8 to 13) with only one [7] referring to UHIs.
At the same time in LL 299 Authors refer to publications that already prove that too much vegetation (trees) in urban canyons can lead increased to particulate matter concentrations (refernces from 41 to 54). Why these title ar not mentioned here? So what is the research gap to be filled in by this study? It should be more clearly stated.
L 110: spelling - should be: methodology
L 112 - what does "the high artificial covering rates" stand for? do you mean conrete surfaces? non-permeable surfaces?
L 118: 3.1 Subsection??? at the end of the sentence
after line L 118 should be at least a brief overwiev of the study methodology - It is OK that a detailed description of the siumulation is provided below, but you need to include here an explanation that you implement a theoretical 3D simulation in order to modify and examine the parametres of temperature and air quality while you provide different green solutions. When this is missing the logic of the text is interrupted.
Table 2 - values describing contribution of vehicle category to overall traffic (%)
are in both columns the same... What does that mean?
LL 167-168: "most frequently used types of street greenery planning, including grass, green belts, and roadside green areas" these type of street greenery acn be understood in varius ways - I suppose they are type of green surfaces as a piece of lawn (grass), green belts (shrubs around a flowerbed?)???
You are reffring here to guidelines/standardsof particular city - please provide a table with the graphic explanation ( a section?) because it is not clear (Figure 2 suggests something but on the plan it is not clear).
Table 3 - You use here LAD parameter with no explanation where it was teken from (you mention it in the literature review briefly) but there is no legend to this table and no source.
L 187 you should indicate that the case study site is theoretical, otherwise it suggests that you might have chosen a real location.
Placement of Table 4 leaves an empty page in the paper
LL 279 to 296
When you describe the changes in microclimate and particulate matter concentration you can organize the text in a more clear way.
When you describe the situation when tree occupancy 280 was increased from 12 to 45% you can list all the changes in parametres in a form of bullets.
You use here also abbreviation WS (wind speed?) with no previous explanation.
LL 408-410 should be canceled
Author Response
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript addresses a relevant and timely topic that contributes to the scientific field of study and is pertinent to the journal's subject matter.
The structure of the paper is clear, the objective and the methodology applied are neatly presented.
The readability of the results can be a bit confusing in some parts of the manuscript. For example, to explain the results shown in figure 3 and 4 graphics, a table could be included to facilitate a more fluent comparison and understanding of the explanatory text (lines 265-296).
The study shows the simulation model developed to contrast the efficiency of tree, shrub or grass planting following Seoul current standards. But, the question that arises is: which specific types of greenery/species are considered in the simulation?
For example, in Fig. 1, there is a lack of distinction between the different types of trees, grass and shrubs. It should be considered that this may be confusing for the reader, as it is not explained if factors such as the differentiation between species is something relevant to consider in the results, or if it is adequate to speak in broader terms about each section.
Concerning the different types of trees and shrubs, in the simulation model developed, apart from whether the leaf is deciduous or evergreen, has a difference between species been taken into account, or has an approximate average parameter been established? Seoul recommend a total of 113 different species of greenery: 48 trees, 38 shurbs and 27 groundcovers. It will be relevant to be more precise in terms of the specific characteristics of the modelling. For example there are 89 species of deciduous leaves in the official Seoul catalogue. Do they all have the same result or has an average been considered? Do some species perform better than others? The interest of this aspect is to see if different shrub or tree species offer a variation in the results of dispersion or fixation of suspended particles.
Finally, it would be very useful to noting in more depth the implications of the findings, in relation with previous studies and giving suggestions for future work.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The text was significantly improved and all the issues were addressed.
The study is now complete and worth publishing.
Congratulations for the Authors!
The paper needs just some layout editing since there is an empty page.
Please check the text to avoid spelling and typesetting mistakes.
