the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 08 Jun 2023
Intra-event evolution of elemental and ionic concentrations in wet deposition in an urban environment
Abstract. Wet deposition is a crucial process that affects the lifetime of atmospheric particles by allowing them to be deposited by two different mechanisms, namely below the cloud and in the cloud. In order to estimate the mechanisms implied in the wet deposition, a measurement campaign was carried out in the Paris region to monitor the evolution of the chemical composition of wet deposition during rainfall events. Eight rain events have been sampled. The latter had different meteorological conditions, atmospheric dynamics and aerosol particles concentrations. Concomitant measurements of the chemical composition of aerosol particles and wet deposition allows calculating washout ratios from measurements taken at the beginning of the rainfall events, before the dilution effect occurred, and showed an increasing trend with increasing rainfall rates. The intra-event evolution of the chemical composition of wet deposition revealed the predominant role of meteorological parameters and local sources in the observed mass concentration variability. The contributions of in-cloud and below-cloud scavenging mechanisms were estimated for some rainfall events and found to vary depending on the specific sources, atmospheric dynamics and meteorological conditions. Overall, this study highlights the variability of wet deposition and its chemical composition, and the need to consider the specificities of each event to fully understand the underlying mechanisms.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
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Supplement
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(3280 KB) - Metadata XML
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Supplement
(894 KB) - BibTeX
- EndNote
- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2023-1022', Anonymous Referee #1, 27 Jun 2023
This study provides a very useful data set on precipitation scavenging of atmospheric aerosols, which, if properly analyzed, can generate quite some useful information for improving our understanding on this topic. The manuscript covers too wide a scope (e.g., source apportionment of PM in addition to precipitation scavenging) and has too detailed description of each single event, ending up lacking in-depth analysis of key factors/parameters dominating the scavenging process. I have the following comments that may hopefully help improve the presentation quality of this manuscript.
Specific comments:
Abstract needs a major rewriting. It only describes what has been done, but lacks of a good summary of major findings, especially some quantitative statements, such as the relative contributions of ICS and BSC to the total wet deposition, the range of WR values for some major chemical species investigated here.
Introduction needs a revision to better describe the major goals of this study and related background information (current knowledge). Very basic knowledge should only be briefly mentioned. For example, a large portion of materials in the first three paragraphs is not really needed. While the three objectives (lines 86-91) listed in this section are somewhat important, it would be even more important to quantify the scavenging rate under different meteorological and chemical conditions, and this should be listed as a major goal too. For example, WR values for the investigated chemical species would be very useful for future wet deposition studies, as demonstrated in Mamun et al. (2022, JGR Atmospheres, 127, e2021JD035787) for elements and Cheng and Zhang (2017, ACP, 17, 4711-4730) for ions. It would be even better if WR values for PM2.5 (fine) and PM2.5-10 (coarse) were calculated separately and summarized in Abstract and/or conclusion section.
Line 255: Such a conclusion/finding is likely because of the very small dataset, in which the impacts of several dominant parameters (rain rate and PM concentration) on total wet deposition cancelled each other, resulting poor correlations between wet deposition flux and these parameters. It would be more useful to investigate WR value under different precipitation rate or PM concentration and generate some useful conclusions.
Line 260 and below: The precipitation scavenging data presented in this study would be more useful for investigating precipitation scavenging of atmospheric aerosols, rather than for source apportionment analysis. Discussing air mass trajectory and potential sources of PM add little new knowledge to the topic of precipitation scavenging. Besides, there are numerous studies on PM source apportionment in literature, but very limited studies on precipitation scavenging of atmospheric aerosols using sequential sampling approach. The authors are encouraged to focus more on aerosol scavenging and generate new knowledge that can be used by the scientific community for future wet deposition studies. It seems to me that the data collected in this study can also be used for generating another important parameter, scavenging coefficient, that is typically used in chemical transport models (see Wang et al., 2010, ACP, 10, 5685-5705).
Section 4 Discussion: most discussions are descriptive of single events, although a brief comparison with literature was provided. I would like to see more in-depth analysis that can provide some definitive or quantitative statements on the dominant factors controlling aerosol scavenging by precipitation.
Section 5 Conclusion: I have similar comments on this section as I have on the Abstract.
Minor comments:
Line 15: Why use “The latter” when you only have one thing mentioned in the proceeding sentence?
Lines 16-18: fix the grammar issue in this sentence.
Line 44: Is WR defined here the same as “the scavenging ratio” frequently used in literature? Better clarify this point here.
Line 94-96: better write this way: “The sampling site is located at the air quality station operated by the Interuniversity Laboratory of Atmospheric Systems (LISA), which is inside the University of Paris Est Creteil (UPEC)…..”
Line 167: change “scavenging” to “scavenged”
Line 201-203: difficult to understand.
Citation: https://doi.org/10.5194/egusphere-2023-1022-RC1 -
RC2: 'Comment on egusphere-2023-1022', Anonymous Referee #2, 19 Jul 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1022/egusphere-2023-1022-RC2-supplement.pdf
- AC1: 'Comment on egusphere-2023-1022', Thomas Audoux, 01 Sep 2023
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2023-1022', Anonymous Referee #1, 27 Jun 2023
This study provides a very useful data set on precipitation scavenging of atmospheric aerosols, which, if properly analyzed, can generate quite some useful information for improving our understanding on this topic. The manuscript covers too wide a scope (e.g., source apportionment of PM in addition to precipitation scavenging) and has too detailed description of each single event, ending up lacking in-depth analysis of key factors/parameters dominating the scavenging process. I have the following comments that may hopefully help improve the presentation quality of this manuscript.
Specific comments:
Abstract needs a major rewriting. It only describes what has been done, but lacks of a good summary of major findings, especially some quantitative statements, such as the relative contributions of ICS and BSC to the total wet deposition, the range of WR values for some major chemical species investigated here.
Introduction needs a revision to better describe the major goals of this study and related background information (current knowledge). Very basic knowledge should only be briefly mentioned. For example, a large portion of materials in the first three paragraphs is not really needed. While the three objectives (lines 86-91) listed in this section are somewhat important, it would be even more important to quantify the scavenging rate under different meteorological and chemical conditions, and this should be listed as a major goal too. For example, WR values for the investigated chemical species would be very useful for future wet deposition studies, as demonstrated in Mamun et al. (2022, JGR Atmospheres, 127, e2021JD035787) for elements and Cheng and Zhang (2017, ACP, 17, 4711-4730) for ions. It would be even better if WR values for PM2.5 (fine) and PM2.5-10 (coarse) were calculated separately and summarized in Abstract and/or conclusion section.
Line 255: Such a conclusion/finding is likely because of the very small dataset, in which the impacts of several dominant parameters (rain rate and PM concentration) on total wet deposition cancelled each other, resulting poor correlations between wet deposition flux and these parameters. It would be more useful to investigate WR value under different precipitation rate or PM concentration and generate some useful conclusions.
Line 260 and below: The precipitation scavenging data presented in this study would be more useful for investigating precipitation scavenging of atmospheric aerosols, rather than for source apportionment analysis. Discussing air mass trajectory and potential sources of PM add little new knowledge to the topic of precipitation scavenging. Besides, there are numerous studies on PM source apportionment in literature, but very limited studies on precipitation scavenging of atmospheric aerosols using sequential sampling approach. The authors are encouraged to focus more on aerosol scavenging and generate new knowledge that can be used by the scientific community for future wet deposition studies. It seems to me that the data collected in this study can also be used for generating another important parameter, scavenging coefficient, that is typically used in chemical transport models (see Wang et al., 2010, ACP, 10, 5685-5705).
Section 4 Discussion: most discussions are descriptive of single events, although a brief comparison with literature was provided. I would like to see more in-depth analysis that can provide some definitive or quantitative statements on the dominant factors controlling aerosol scavenging by precipitation.
Section 5 Conclusion: I have similar comments on this section as I have on the Abstract.
Minor comments:
Line 15: Why use “The latter” when you only have one thing mentioned in the proceeding sentence?
Lines 16-18: fix the grammar issue in this sentence.
Line 44: Is WR defined here the same as “the scavenging ratio” frequently used in literature? Better clarify this point here.
Line 94-96: better write this way: “The sampling site is located at the air quality station operated by the Interuniversity Laboratory of Atmospheric Systems (LISA), which is inside the University of Paris Est Creteil (UPEC)…..”
Line 167: change “scavenging” to “scavenged”
Line 201-203: difficult to understand.
Citation: https://doi.org/10.5194/egusphere-2023-1022-RC1 -
RC2: 'Comment on egusphere-2023-1022', Anonymous Referee #2, 19 Jul 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1022/egusphere-2023-1022-RC2-supplement.pdf
- AC1: 'Comment on egusphere-2023-1022', Thomas Audoux, 01 Sep 2023
Peer review completion
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Benoit Laurent
Karine Desboeufs
Gael Noyalet
Franck Maisonneuve
Olivier Lauret
Servanne Chevaillier
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(3280 KB) - Metadata XML
-
Supplement
(894 KB) - BibTeX
- EndNote
- Final revised paper