Compositional Characteristics of Atmospheric Aerosols during a Consecutive High Concentration Episode in Seoul, Korea
Round 1
Reviewer 1 Report
Review of the manuscript on “Compositional Characteristics of Atmospheric 2 Aerosols During a Consecutive High Concentration Episode in Seoul, Korea” by Hee-Jung Ko et al.,
Authors have attempted to characterise the chemical and optical properties of dust-laden and mixed pollution-dust containing aerosols from Korea using a broad suite of instrumentation. Although the manuscript is technically sound some unclear description and redundant statements make the readability not smooth. Therefore, I recommend this manuscript for major revision. Please find my comments below.
Line 20-21: These sentences are redundant and same as those described in 17-19. Composition is higher?? This is obscure sentence, delete it or change for clarity.
Line 24-25: Sentence is not clear with phrases like “presumed to have” and “secondary pollutants of fossil fuel combustions”
Line 26-27: when mentioning 5-6 sources, how come they are main sources? these are all possible sources.
Abstract needs complete rewrite up with more obvious outcomes.
Line 33: change “roles” to “role”
Line 38: change “mineral dusts” to “mineral dust”
Line 40: “dust” is repeating in this sentence, avoid such redundancy.
Line 41: so many plural forms –“concentrations, sizes, and compositions, sources, aerosols, processes.”--??
Line 86: What about the quality assurance details for the analytical protocols described here in this manuscript?
Figure 1: What is the source of this maps? Mention the reference in the figure caption.
Line 127-128: This is redundant, see line 120-121.
Line 143: What about the acid uptake on mineral dust particles, which enhances the soluble Mg2+ and Ca2+ concentrations during transport? How sensitive this calculation for the aforementioned processes?
Throughout the manuscript, I am confused with one thing, dust frequencies or episode increase in late spring to early summer over E. Asia. So how relevant this study is with a focus on composition of dust-laden aerosols?
Line 150-156: one night period here referred as “haze” on December 31 and another such one on January 1 is referred as “mixed haze-dust”-this is causing confusion.
Line 157-169: What is the composition ratios of the ionic species? This paragraph is not clear.
What is “1.38” and “3.67” in equation 2 and “0.27” and “4.44” in equation 4? Please describe them explicitly although ref. is mentioned.
What is the neutralization factor in Figure 5? Explain this more explicitly.
In Table 1. Highlight that significant correlations here.
Figure 6. Fill the pies with colors and correct the typos within the figure text- “constrcutio” and “n” are separated.
Author Response
Dear editor
We revised our manuscript in accordance with the comments of the reviewers as follows.
Author Response File: 
Author Response.docx
Reviewer 2 Report
This manuscript presented characterization of temporal variation, chemical composition, and emissions sources of aerosols during a winter period in Seoul of South Korea. The topic of this study fits within the scope of this journal, e.g., aerosols and/or air quality. However, the duration of the observation experiment was only 3-4 days, which may be not enough to make implication for local and/or regional air quality. I would believe that the authors made efforts to prepare the manuscript, but the importance and necessary of this study have not been well explained, as well as scientific question was not clear, for example in the introduction section. I suggest the authors to further describe why you performed such a short-term campaign instead of the longer, what scientific question you need to answer, etc. In addition, such a short campaign provided a limited amount of the data for statistical model analysis as used by this study (i.e., principal component analysis), which may bring a large uncertainty that has to be further evaluated. The findings and conclusions of this study are more or less well-known knowledge, which may have limited interesting for international atmosphere science communities.
Personally, the section of ammonium salt formation seems more interesting, but the authors could further investigate effect of the dust aerosols on particulate ammonium formation in more detail. Use of gas precursors (SO2 and NO2) data of sulfate and nitrate, to calculate oxidation ratios (SOR and NOR) of them, could help to further understand if the limited production of particulate ammonium nitrate is due to local emissions and/or long-range dust transport, or others. Thermodynamic model (e.g., ISORROPIA-II) could be applied here to further investigate that, as well as ammonium neutralization, aerosol acidity (for this you need to estimate gas-phase ammonia and nitric acid concentrations at your sampling site when you run the model using the “forward mode”) and water content, as influenced by the Asian dust aerosols. In addition, the geographic origins of the Asian dust should be explained by using some tools, e.g., air masses back trajectory analysis (PSCF or CWT). To do this, it should be better to increase your observation data duration to get more accurate results. Moreover, a longer database could also improve understanding of the concerns related to air quality in the past in Seoul during wintertime.
Generally, this paper was well-written, but it is essential for check typographical errors, and grammatical correctness. The data quality to be further validated. For an example in Figure 2, the visibility data looks like a same value at beginning, why?. The order of tables 1 and 2 should be checked. Overall, I do not recommend this paper can be accepted before significant improvements as I commented above, for instance.
Author Response
Comment:
Use of gas precursors (SO2 and NO2) data of sulfate and nitrate, to calculate oxidation ratios (SOR and NOR) of them, could help to further understand if the limited production of particulate ammonium nitrate is due to local emissions and/or long-range dust transport, or others.
Reply:
There was no gas precursor (SO2 and NO2) measurement data on-site. Therefore, the calculation failed.
We calculated SO2 and NO2 with the surrounding area data. SOR showed a range of 0.04-0.16 and NOR was in the range of 0.03-0.18. As a result, it is impossible to accurately distinguish between local and long-range transport pollutants because they were not observed in the same region.
Comment:
Thermodynamic model (e.g., ISORROPIA-II) could be applied here to further investigate that, as well as ammonium neutralization, aerosol acidity (for this you need to estimate gas-phase ammonia and nitric acid concentrations at your sampling site when you run the model using the “forward mode”) and water content, as influenced by the Asian dust aerosols.
Reply:
We will secure a lot of data and study it later.
Comment:
In addition, the geographic origins of the Asian dust should be explained by using some tools, e.g., air masses back trajectory analysis (PSCF or CWT).
Reply:
We added text to the manuscript to conform with the reviewer’s comment. (Lines 186-196)
“Figure 5. shows the 72-h air mass backward trajectories at a height of 500 m, colored according to the concentration of the ionic component pollutants. The backward trajectories were similar for the haze and mixed haze-Asian dust episodes, while air masses for the Asian dust case seemed to move faster than those for the other cases. NO3-, SO42-, NH4+, i.e., the anthropogenic pollutants, showed elevated concentrations when the trajectories passed over the industrialized area in East China. During the Asian Dust period, the air masses passed over Mongolia and Inner Mongolia, the major Asian Dust source regions, and Ca2+, mainly originating from soil dust, showed higher concentrations.”
Comment:
To do this, it should be better to increase your observation data duration to get more accurate results. Moreover, a longer database could also improve understanding of the concerns related to air quality in the past in Seoul during wintertime.
Reply:
We added text to the manuscript to conform with the reviewer’s comment.
(Lines 57-59)
“This period was selected as a case study of dust and sand storm (DSS) events by working group-1 (WG1) of the Tripartite Environment Ministers Meeting among China, Japan, and Korea (TEMM) (http://www.teem.org).”
Comment:
Generally, this paper was well-written, but it is essential for check typographical errors, and grammatical correctness.
Comment:
The data quality to be further validated. For an example in Figure 2, the visibility data looks like a same value at beginning, why?.
Reply: We re-checked the data, but there was nothing wrong with them.
Comment:
The order of tables 1 and 2 should be checked.
Reply: The table sequence was modified as requested.
Comment:
Overall, I do not recommend this paper can be accepted before significant improvements as I commented above, for instance.
Reply:
The manuscript was revised overall.
Round 2
Reviewer 2 Report
The authors have overall addressed my comments. This paper might be accepted.
Author Response
Dear editor
We revised our manuscript in accordance with the comments of the reviewers as follows.
Comment:
Lines 122-123: Therefore, it was determined that the high concentration of air was introduced after 09:00 KST
Do the authors mean "high concentration of dust" or something else? Presumably, it isn't the high concentration of "air" that they mean.
Reply:
We revised the sentence for clarity (Line 124-125)
|
before |
after |
|
Therefore, it was determined that the high concentration of air was introduced after 09:00 KST. |
Therefore, it was determined that the high concentration of air mass was introduced after 09:00 KST. |
Comment:
Additionally, there are a few places where there are formatting issues (commas at the beginning of a line, rather than following the word or ion on the previous line) that should be fixed.
Reply:
The manuscript was revised overall. ( Red color )
Author Response File: Author Response.docx
