Dear Marco,

thank you very much for the revision of the manuscript which improves the paper significantly.
Before being accepted for publication, please consider the minor revisions requested by referee #1; see below. After having received the revision, I will decide quickly on acceptance.

Thank you for your cooperation.

Best wishes

Andreas


Report #1:
The authors have done a great job of responding to almost all of my comments. The paper flows much better! I just have a few minor things that I think should still be addressed or at least considered.

Response #1 about comparing with Zanatta
That’s a great addition. Lines of constant SSA could be added to the plot. I know you mentioned (response#2) that someone else is writing an SSA paper, but adding those lines shouldn’t interfere with that SSA project.

Response #13 about skewness
The authors added some more text about skewness but it doesn’t actually get at what I was asking about. ? I was hoping to see something more in the context of aerosols and less mathematical. With the new text I still don’t think it’s really clear why a reader should care about skewness or what the implications are for aerosols. For example, what does skewness say about extreme events (if anything)? Or aerosol variability? Etc…

Response #15 about cut sizes
The authors did a bunch of work to look at this question of whether inlet cut size changes affected the resulting aerosol climatology at the sites they looked at. I don’t think the figures they generated to respond to this question need to be added to the manuscript or supplemental materials but I think it would be useful to add one or two sentences to the manuscript to reflect this additional work they did. For example, right now there’s a sentence that says “Consequently, the inlet change from PM1 to PM10 at KPS had probably only a minor effect on SAE.” The authors have now looked at the data and can say something a little more definitive than ‘probably’.

Also, there should be some mention of size cut changes in the methods section. I think the way to do this is to make an additional methods section: 2.2.2.4 ‘Inlet size cut changes’. There the authors should note that inlet size cut change could potentially affect both scattering and SAE and trends. I would move the parts of the second paragraph of section 3.2 describing the inlet size cut changes and previous investigations on the effects of size cut changes to this new section. Then I would suggest adding a few sentences to section 2.2.2.4 saying that the authors looked at climatologies of SAE (and scattering?) for different inlet sizes and for different time periods for and didn’t see any obvious changes in the climatology as a function of size cut due to interannual variability (although I’m not sure that’s totally true for KPS!). Then in section 3.2 you can just refer to section 2.2.2.4. Also in section 3.6 where you mention size cut issues you can again refer back to section 2.2.2.4.

Note: the manuscript says that MSA and MAD changed from PM2.5 to PM10 but the plot made for MSA in the response to the reviewers for comment#15 only shows box whiskers for changes between whole air and PM10. Not sure if that’s a typo.

Section 3.1.3
Last sentence refers to ‘Paragraph 3.5’ – do the authors mean section 3.5?

Figure 9
The discussion about Figure 9 in Section 3.5 would probably be easier to follow if the y-axes for g and SAE were the same for all plots.

Figure S1
The dashed vertical lines are really hard to see. Could you make them solid like the other two lines?

Dear Marco

thank you for the careful revision of the manuscript. It is now accepted for publication in ACP. I only request one very minor technical corection to the new Figure S1. You should indicate at some point that the x-scale refers to relative humidty. I is mentioned in the figure caption, but it should appear also in the figure itself.

Then, please send the email of the new co-author to the editorial office.

Best wishes

Andreas