Dear authors,

Thank you for the answers to the referees and the revised version. I have got one positive review from one referee following this. Although you fulfilled most of the referees requests, some addionnal work is necessary before publication.

Answers to Referee 1:

9. The bias in AOD is much smaller compared to bias for the surface stations. Can the authors discuss the reason for this?

Please discuss this point in the paper, and try to give a more specific response than that given to referee one.


Answers to Referee 2:

1. How the results of the present study compare with these earlier studies?

P10,l36: Please name the differences in sulfate you make reference to.


2. Also in all tables and throughout the manuscript where reference is made to budget, it has to be clarified they concerne PM10 aerosol (or is it bulk aerosol in the model?)

Could authors please add this information (on use of bulk aerosol as a target) also in Figure 7 and Tables 12 and 13.
I would have prepared having budget calculations for PM10, which is more easy to reference. Could authors please discuss qualitatively, by looking at size distributions for PM species, how results would be different for PM10.

4. Section 2.1 MOCAGE model Information is missing on how the aerosol size is parametrized in the model. Since later in the discussion the authors refer to the aerosol sizes are taken into account in the model and how they change during atmospheric aging.

Authors say, that there is no effect of ageing on aerosol size in the model. Certainly , there are many processes in the model which act on aerosol size over time, such as condensation or sedimentation. May be authors want to say that effects of these processes on size distribution are small, but even this would be surprising.


21. Page 9, line 15-18: Nitrate aerosol partitioning to the aerosol phase is very sensitive to the aerosol pH (Guo et al., 2016) and NH4NO3 is semi volatile. How well is this computed in your model? Do you consider dust aerosol alkaline components in ISORROPIA calculations?

Please discuss this point also in the revised manuscript. How much more nitrate would you expect, when taking into account alkaline compounds from dust ?
I am quite convinced that ChArMEx provides data on alkaline compounds, or likewise data on coarse mode nitrate which are probably bound to such ions.

For Pacific Ocean, Fairlie et al. (2010) address this problem and give many references on other relevant studies.


Answers to Referee 3:

1. The authors should make more clear the connection to the ChArMEx and the choice of the years, since they have not at all made any use of the campaign’s data.

Even if 2012 and 2013 PM composition data from Cape Corsica are indeed not in the SEDOO data base, I think they would be available from the PI (Jean Sciare), if needed. PM1 composition data from SOP2 (July, August 2013) are available and published, for example in Michoud et al., 2017. I recommend that authors use at least these SOP2 data for model evaluation.



References

Fairlie, T. D., Jacob, D. J., Dibb, J. E., Alexander, B., Avery, M. A., van Donkelaar, A., and Zhang, L.: Impact of mineral dust on nitrate, sulfate, and ozone in transpacific Asian pollution plumes, Atmos. Chem. Phys., 10, 3999-4012, https://doi.org/10.5194/acp-10-3999-2010, 2010.

Michoud, V., Sciare, J., Sauvage, S., Dusanter, S., Léonardis, T., Gros, V., Kalogridis, C., Zannoni, N., Féron, A., Petit, J.-E., Crenn, V., Baisnée, D., Sarda-Estève, R., Bonnaire, N., Marchand, N., DeWitt, H. L., Pey, J., Colomb, A., Gheusi, F., Szidat, S., Stavroulas, I., Borbon, A., and Locoge, N.: Organic carbon at a remote site of the western Mediterranean Basin: sources and chemistry during the ChArMEx SOP2 field experiment, Atmos. Chem. Phys., 17, 8837-8865, https://doi.org/10.5194/acp-17-8837-2017, 2017.

Dear authors,

Thank you for your answers.
While I still regret, that you did not use any Charmex measurements, I acknowledge the point you make on the difficulty on getting these data.
There is one point left, the omission of soluble dust ions cations in your calculations. The coarse fraction of nitrate and also sulfate could be strongly enhanced, if this was included, as you are already discussing.
I ask you three “easy to implement” modifications to have a fair treatment of this issue.

1) When citing Hodzic et al. 2006, please discuss specifically the Mediterranean region, which is much more affected by the problem than average Europe.

2) Due to this omission, your SIA budget would be closer to a fine aerosol (PM2.5) SIA budget, than a total aerosol SIA budget.

3) Please make clear these limitations also in the conclusions. In perspectives, please state that for a full treatment of (total) aerosol SIA budget, soluble dust cations, and also sea-salt cations should be included.

Best regards,
Matthias Beekmann