Dear Authors,

Thank you very much for responding carefully to the two reviewer comments. They were both satisfied with the responses, but they did have some remaining minor comments to address. As a result, I recommend that this be accepted pending very minor comments. I'm pleased to accept this soon for ACP.

Hope you all are doing well. Sincerely, Jason Surratt

Comments to Consider from the Reviewers:

Reviewer 1:

I recommend that the authors should add a short bit of text, either to the manuscript or the supplemental that addresses the reviewer 2's comment- that volatility and seasonal trends are linked.


Reviewer 2:

I thank the authors for taking time to revise the manuscript. The authors have addressed the comments adequately. However, I have two minor comments.

1. OM/OC ratio. While I agree with the authors that both Aiken and Canagaratna parameterizations are uncertain for this dataset, I want to point out that the OM/OC ratio would affect the recovery ratios determined by Eq. (6). Higher OM/OC ratio from Canagaratna parameterization would lead to lower recovery ratio and hence higher ambient concentration of factors.

2. It is important to discuss why the same Rz is selected for both B-OOA and S-OOA (i.e., response to comment#20) and mention that the Rz of OOA factors warrants further investigation in the manuscript.