Dear authors,

I have received further comments from Referee 1 regarding the manuscript. Please see attached. Specifically, more details about PMF analysis should be provided, as well as better explanation of the diurnal trends of some factors (for instance SV-OOA). I think the inclusion of such information/discussion will greatly improve the clarity of the manuscript. Please address the comments and submit a revised manuscript.

Best regards,
Sally

Dear authors,

Most of the further comments from Referee 1 have been addressed. To further improve the clarify of the manuscript, I suggest the following information to be included:

1. An unexplained mass of 7% for the warmer period is fairly large. More details on the residuals should be provided for both the warm period and the cold period for the readers to gain a better understanding of the residuals. Please at least include these plots , 1) Q/Qexp vs. number of factors, 2) Distribution of scaled residuals for each m/z, 3) Time series of the measured and the reconstructed organic mass, 4) Q/Qexp vs. time, 5) Q/Qexp vs. m/z.

2. Are the rotational ambiguity of the solutions and the robustness of the solutions explored with the use of FPEAK and SEED parameters? If so, please provide relevant discussions/results. If not, please explain why these are not examined.

3. In the response, the authors have provided further info regarding the correlations (R2 values) of PMF factors with external tracers. Currently, these values are included in the text here and there. In order to offer a clearer overview of these correlations for the readers, please provide a summary figure (or table) in the SI showing the correlations of each PMF factor with all the external tracers considered. Please do so for both the summer data and winter data. As the authors suggested that the specific characteristics of Montseny might lead to better (or worse) correlations of some PMF factors with certain external tracers, these summary correlation figures would be useful references for future studies in the area.

Once these are included in the revised manuscript/SI, the manuscript will be acceptable for publication in ACP.

Best regards,
Sally

The authors have sufficiently addressed all the comments. The manuscript can now be published in ACP.