Contribution of Phoretic and Electrostatic Effects to the Collection Efficiency of Submicron Aerosol Particles by Raindrops

Round 1

Reviewer 1 Report

 

Contribution of phoretic and electrostatic effects to the collection efficiency of submicron aerosol particles by raindrops

This research uses BERGAME setup for collection efficiency quantification of submicron aerosol particles by raindrops. The author tried to demonstrate his experiment design outperformed previous model results. However, the unclear scientific discussion makes the understanding this research frustrating.  There are unfinished sentences and grammar mistakes throughout the manuscript.  I can only recommend this manuscript accepted after a major revision. The scientific questions should be clarified, and the experiment design needs major improvement. The organization of the manuscript is problematic and messy.

 

General Comments:

1. Grammar check is needed for this article. For instance, line 16 “However measurements”; line 17 “Indeed measurement”; line 30, “they participate”. There are numerous basic grammar mistakes throughout the manuscript. Please grammar proof carefully.
2. Line 27, acronym needs to be shown in full context at first appearance. “MT”
3. Line 43, reference is needed.
4. Line 199, too many “and” here.
5. Line 208, “seem to indicate” sounds like you are not sure about what you read.
6. Line 212, define “large dielectric” that can be treat as conductor.
7. Line 257, please delete the first sentence here.
8. Line 259-292, these paragraphs should be moved to the information or background sections, but in discussion.
9. Line 305-306, this is a very strong statement based on speculations. If you cannot prove specifically where other models went wrong, please rewrite. Just because others result is different from this study cannot conclude other models are wrong.
10. The discussion section is poorly organized. If you have both result and discussion sections, no new figures should be presented in the discussion section.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Lemaitre et al. employed experimental and theoretical comparisons to show that phoretic forces have a major impact on the below-cloud scavenging of submicron aerosols. The topic of this study fits the Atmosphere journal and the manuscript is overall well written and organized. I recommend for publication after some minor revisions.

1. Eq. 1: please define d_ap and C here. What is the unit of C, number/volume, or mass/volume?

2. Eq. 2: what is N(D_drop)? If it represents the distribution, a lower case n may be better since Fig. 7 uses N as the number concentration.

3. L87: what does "0.4 et 0.6" mean?

4. What is the purity of water in the drop generator, i.e., what is the conductivity?

5. Eq. 3: please keep consistent with d_ap and define q_ap here. How is 2/3 from? What are the units of fluorescein in the chamber and the droplet?

6. Eq. 4 is an implicit function. It is better to mention how d_ap is derived.

7. Fig. 6: where are the purple points? What does the green point at 38^oC mean?

8. Fig. 8: please use a different color for S and A

9. It will be better to have a scheme showing phoretic and electrostatic forces of droplets to aerosols, where the differences are highlighted.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Overall:

 

            The paper is interesting and has scientific importance in terms of knowledge on the collection efficiency of aerosols through raindrops.  The experiment shows how the phoretic forces have a major impact on the below-cloud scavenging of submicron aerosols at certain RH conditions.

 Even though I would like to suggest modifying the abstract which mentions “a 100 % increase of the collection efficiency for each 17 percent decrease in the atmospheric relative humidity“ the results mentioned here are in the range of 26-36 % and generalizing the increase would be misleading. Or can mention the RH range along with the results in abstract. From the conclusion, I understand that complimentary results in a wider RH range are needed to generalize this comment.

 

Apart from that the manuscript is well written and  I recommend the manuscript to be published after addressing a few minor comments.

 

Minor Comments:

1. Line 50: This sentence can be changed to “ …limited by two wet deposition processes in the atmosphere”.
2. Line 52: ‘scavenging processes’
3. Line 77-79: consider to rewrite the first part of this sentence.
4. Line 88: ‘(?_??=0.4 to 0.6 μ?)’

Comments for author File: Comments.pdf

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors responded all my comments and I have no further comments.