Dear Authors

You have revised the manuscript following the comments and suggestions and significantly improved the manuscript. Therefore, I decide to accept for publication. However， you should check the reference one by one and make sure they are right.

he paper by Wu et al. analyses desert dust aerosol composition at two sites, one close to the source in Asia and the other one in an urban area after 700 km transport, and investigate the possible formation of nitrates and sulfates due to particle chemical aging during transport. The main conclusion of the paper is that very small quantities of sulfates and nitrates are observed after transport compared to dust close to their lifting source. The authors argue that sulfate and nitrate production reported by previous studies for dust are more likely due to local production on urban mineral particles or soil derived components that chemical reactions on dust.
Based on past literature (both field and laboratory studies) and the careful analysis of the methodology and results presented in this paper, I feel to recommend the paper to be considered for publication on ACP only after substantial revisions. These revisions to me mostly concern the presentation and discussion of the data and the conclusions. In fact, I mostly agree with one of the two reviewers in stating that the conclusions drawn here are not really supported by the data, i.e. only one case of source and transported dust is analysed here and also not the same dust episode is investigated but two different ones. The authors answered this comment saying that it is not necessary to have too many observations to obtain a good result (and that the two dust cases analysed are comparable), and I agree with that, but at the same time I find the conclusions they gave in the paper too much conclusive considering the provided dataset. I would avoid generalizing the results and conclude that sulfate and nitrate observed in previous studies are in reality for the most part probably not linked to reactions on the dust surface. Many different field conditions have been found in the literature, i.e. temperature, relative humidity, or precursor gas concentration, and may explain the different findings. Probably the authors should go deeper to all past literature and compare all the conditions/results to be able to state more general ideas (indeed some useful discussion is already provided in Sect. 3). But also in this case the single observation provided in this study is not sufficient to me to contradict previous studies. It may provide new results that can be considered in conjuction with previous ones. For this reason I feel also to agree with the other of the two reviewers in considering this dataset as potentially very useful to the scientific community and for this reason worthy of being published.
So, in conclusion I would encourage the authors to « smooth » their conclusions and to revise / extend the discussion of their data / results and to put them better in the literature context so to give the reader the appropriate elements to evaluate the significance of the provided dataset.

Specific comments
I will give just few specific comments since a large part of my comments/questions have been already raised by the other two reviewers.
Abstract, line 9-10 (and generally in the text) : I would replace the verb « indicate » with « suggest » or similar when you state on some conclusive statement which could be not really proven

Introduction, page 3, line 26 : to me it is not really a matter of different results but probably of different conditions leading to different reactions on dust. I would To me the question is : why there are so much different rates of production of sulfate and nitrate during dust transport to polluted areas ? And what you bring with your study is an other observation to add to the piece of work already done in the literature to try to understand the chemistry/aging on dust.

Section 2 : based on your sampling and analysis protocol I wonder if you do not risk to lose your sulfate and nitrate before analysis. Supposing that these are liquid coatings on dust, are you sure that they do not evaporate from dust efore analysis ? This is a key point of the methodology that should be discussed in the paper.

Section 3 : which is the uncertainty on the mass percent of sulfate and nitrate you obtain ? The values at the source and trabsport region are mostly the same considering the uncertainties ? This is another key element to discuss.

I would encourage the authors to « smooth » their conclusions and to revise / extend the discussion of their data / results and to put them better in the literature context so to give the reader the appropriate elements to evaluate the significance of the provided dataset.