Dear Authors:
Thank you for your response to the referee comments. I have carefully reviewed the revised manuscript and have determined that major revisions are still required. Please consider the comments below. Line numbers refer to the non-track changes version of the revised manuscript. Additionally, please carefully proofread the manuscript and check for standard language usage.

Main
1) Both referees suggested that further citations of previous work are required. Thank you for the incorporating several of the suggested references. However, I agree with referee 2 that this discussion should be included in the introduction, rather than scattered through the paper. Please add this discussion of previous SP-AMS measurements that integrate BC signals into the PMF in the introduction and highlight the differences of your approach. An additional study that you should consider including is Rivellini et al., (2020).
2) Re: Referee 2 comment 11: Same as the referee, I am unable to follow the argument that supports the use of the term HULIS to describe this factor and I also wonder if MO-OOA would be a better description. While I understand that HULIS has been identified in atmospheric aerosol, in my understanding it is essentially an operational definition (similar to various measurements of BC and MO-OOA) that varies depending on the analytical instrumentation used. Moreover, HULIS generally refers to higher molecular weight species. As AMS measurements provide extremely limited information on molecular weight, I tend to agree with the referee that a terminology such as MO-OOA that has been defined based on AMS measurements is more appropriate. As stated by the referee, identification of this factor as HULIS requires “…other co-located measurements in this work can provide evidence that the HULIS factor has some specific chemical features that cannot be described as MO-OOA.”
3) It strikes me that the mass spectra of the fullerene region differs significantly between the different factors. Does this provides any additional insight/information particularly when compared with the Onasch et al., (2015) results?
4) Re: Referee 1 comment 3: I agree with the referee that further information regarding the impacts of the uncertain RIE is required. How was it determined that the RIE did not affect the PMF analysis? Please describe this in the manuscript.

Other
5) Re: Referee 1 comment 4: Please include the time resolution of the measurements (e.g., 10 s, 1 min, etc.). Additionally, from my understanding, the instrument was operated in different configurations (V mode, W mode, extended m/z range V mode as well as with and without the catalytic stripper). It would be useful to explicitly state the time coverage of the measurements (for example every 3rd minute for half hour of every hour).
6) Re: Referee 1 comment 5: Please include this in the main manuscript.
7) Re: Referee 2 comment 7: Please include the both the mass spectra (Fig. 4) and the concentration time series (Fig. 3) in the same plot. Line 222 states that Fig. 4 shows both of these, however, only the mass spectra are shown.
8) Re: Referee 2 minor comments: Please define eBCwb, eBCtr when they are first used (line 206).
9) Lines 22-24 “Positive matrix ….able to do.” This sentence is very difficult to read. Please rewrite to improve clarity.
10) Lines 66- 69: “In this study … metal nanoparticles.” This should be in the experimental section, not the introduction.
11) Sects 2.1 and 2.2: I suggest renaming to better reflect the contents of the section. 2.1 is focused on both the site and the supporting measurements, while 2.2 is only focused on the SP-AMS rather than on all the instruments.
12) Sect 2.2: The text of this section needs to be revised to more clearly describe the instrument as there are several confusing/incorrect statements. For instance (not the only case), line 118 “…the new vaporiser is designed, to detect the vaporized species through electron ionization for the generation of the chemical ion…” is problematic as it implies that the vaporizer detects the species and the term chemical ion is poorly defined.
13) Line 131: I don’t understand why the term isotopes is in parentheses or why it is included in this section. Please explain or revise. The fragments should be identified as ions.
14) Line 140: All the signal is integrated in UMR, not “can.” Also “robust” in what way”
15) Lines 151-153: Please spend a few sentences describing the Corbin et al approach and how this approach is different. The short comment by Corbin may be of help here.
16) Line 156: Please describe more completely how this reflects that the “data and uncertainties have a lognormal distribution.” I did not find this information in the supplement.
17) Figure 1: Why is Sr included in this time-series? It is not referenced in the text.
18) Line 199: From the figure (2b) it appears that rBC starts increasing first. Do you mean to say that the peak signals are at different times? Please clarify.
19) Figure 2: Please standardize the x-axes on the panels to the same range and format (date or date +time). Figure 2b: Please use standard AMS colors and remove the negative charge from the legends.
20) Line 226: Please describe what you mean by “mixing” so readers who are not familiar with PMF analysis more clearly understand the results.
21) For the PMF results without fullerenes included, were the same optimization steps taken as for the PMF performed on the data with the fullerenes (lines 232-236)? Was a 6 factor solution explored and did that improve the results?
22) Figure 4: Please fix the y-axes so that the tick marks do not overlap and that the values can be clearly read. Please increase the resolution of the legend and replace “gt1” with “>1.” Please color HO and Cx differently. In the legend, point out that the magnitude of the fullerene signal varies widely between the factors.
23) Line 345: I think you mean Figure 6 here, not 7.
24) Line 381-382: This sentence confuses me as it seems to imply that this work and Reyes et al suggest that fireworks are a source of soot. Perhaps you mean “consistent with the results reported here and in Reyes at all that fireworks are not soot sources.”
25) Sect. 4.2: I think your figure numbering in the text versus the figures themselves is off. Figure 8 in the text seems to be what is actually labeled figure 7 and likewise for 8/9.
26) Supplement: Please use the HR coloring on the mass spectra as was done in the main text.

References
Onasch, T. B., Fortner, E. C., Trimborn, A. M., Lambe, A. T., Tiwari, A. J., Marr, L. C., Corbin, J. C., Mensah, A. A., Williams, L. R., Davidovits, P., and Worsnop, D. R.: Investigations of SP-AMS Carbon Ion Distributions as a Function of Refractory Black Carbon Particle Type, Aerosol Sci. Technol., 49, 409–422, https://doi.org/10.1080/02786826.2015.1039959, 2015.
Rivellini, L.-H., Adam, M. G., Kasthuriarachchi, N., and Lee, A. K. Y.: Characterization of carbonaceous aerosols in Singapore: insight from black carbon fragments and trace metal ions detected by a soot particle aerosol mass spectrometer, Atmospheric Chem. Phys., 20, 5977–5993, https://doi.org/10.5194/acp-20-5977-2020, 2020.

Dear Authors: Thank you for your consideration of the previous comments. I am happy to accept the paper for publication following attention to the minor comments below. Line numbers refer to the track changes version.
1) Lines 329-333. Thank you for the addition of the text. However, the current wording is confusing to the reader as the description of the Corbin et al results begins by discussing peak width - a parameter not important for UMR. I suggest you start this section off with a sentence describing how the approaches give similar errors (along the lines of the last sentence of this addition) and then describe the Corbin et al approach.
2) Line 245-246: "...ensures quantitatively." --> "...ensures quantitative measurements." or something along those lines.
3) Lines 506-507: "Variables from this and previous publications." Please specify which ones are from previous publications and provide references.
4) Figures 2 & 3: Please improve the resolution of the labels and the axes.

Congratulations!