On the derivation of particle nucleation rates from experimental formation rates

Kürten, A.; Williamson, C.; Almeida, J.; Kirkby, J.; Curtius, J.

doi:https://doi.org/10.5194/acp-15-4063-2015

Articles | Volume 15, issue 8

https://doi.org/10.5194/acp-15-4063-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/acp-15-4063-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 15, issue 8

Research article

|

17 Apr 2015

Research article |

| 17 Apr 2015

On the derivation of particle nucleation rates from experimental formation rates

A. Kürten, C. Williamson, J. Almeida, J. Kirkby, and J. Curtius

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Final revised paper (published on 17 Apr 2015)
Preprint (discussion started on 29 Oct 2014)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC C9457: 'Anonymous review', Anonymous Referee #1, 24 Nov 2014
- AC C12488: 'reply to reviewer #1', Andreas Kürten, 03 Mar 2015
RC C9701: 'Referee comment', Veli-Matti Kerminen, 28 Nov 2014
- AC C12489: 'reply to V.-M. Kerminen', Andreas Kürten, 03 Mar 2015
SC C9990: 'Comment on evaporation', Hanna Vehkamäki, 10 Dec 2014
- AC C12490: 'reply to H. Vehkamäki', Andreas Kürten, 03 Mar 2015

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Andreas Kürten on behalf of the Authors (03 Mar 2015) Author's response Manuscript

ED: Referee Nomination & Report Request started (03 Mar 2015) by Hinrich Grothe

RR by Veli-Matti Kerminen (13 Mar 2015)

RR by Anonymous Referee #1 (23 Mar 2015)

Suggestions for revision or reasons for rejection

The authors have done a very good job in addressing almost all of the comments and the revised manuscript is much better than the original one.

I have only a couple of concerns that still need some thought (or more explanation, in case I have misunderstood or not understood what has been written):

1. section 2.4 (the justification of equation 21):
I still have problems accepting that GR x n = J when self-coagulation is important, and don’t really understand all the details of the justification in the section. First of all, where does the ‘initial equation’ 16 come from? If I understand the equation correctly, it is ‘designed’ in such a way that each collision, between classes m and i, adds to the diameter a certain amount - and these amounts are then summed? Shouldn’t this summation be done (first) for the volumes, and then transformed to diameters? Second, is the Taylor expansion (and the approximation of figure 3) valid with strong self-coagulation, e.g. in the case of sharp nucleation bursts causing a growing narrow mode?
Of course I understand that by ‘defining’ GR = J/n will force the equation to hold, but what does GR mean then? Will it represent anymore the growth rate of an average single particle? And, how is it estimated reliably from experimental data - especially for very small particles for which data can be very noisy?

2. Page 5, line 144 (and figure 1): The “measured” wall loss rate is amazingly smooth?

3. Page 7, lines 211-212 and equation 14: The reference to Lehtinen et al (2007) is probably not a good choice. This relationship (J = GR*n) for condensational growth is much older, and is e.g. in Friedlander’s book ’Smoke, dust and haze’ and also Seinfeld&Pandis, when the continuous condensation equation is derived.

4. Hanna Vehkamäki’s comments on evaporation are interesting. The presence of evaporation also influences the validity of GR x n = J, which is, I believe, strictly true only for a propagating (size distribution) wave. Evaporation deforms the shape of the distribution, by acting as a cause of diffusion in size space. This is another reason why the presence of strong evaporation will likely make the analysis in the manuscript less accurate (?)

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ED: Reconsider after minor revisions (Editor review) (29 Mar 2015) by Hinrich Grothe

AR by Andreas Kürten on behalf of the Authors (30 Mar 2015) Author's response Manuscript

ED: Publish as is (31 Mar 2015) by Hinrich Grothe

AR by Andreas Kürten on behalf of the Authors (31 Mar 2015)

Short summary

The manuscript provides insights into the calculation of new particle formation rates. Generally, formation rates are measured at a diameter which can be substantially larger than the critical size of the newly formed particles. In order to transform the formation rate to a smaller size, a correction needs to be applied. We present a new method to apply this correction which takes into account the effect of self-coagulation.