This manuscript compared carbonaceous aerosol data measured by different sampling and analytical approaches, based on field campaigns (winter and spring) performed at an urban site in Northeast China. Major contributions included that the effects of methanol extraction on EC measurement were clearly explained, and the EC and OC results that were most indicative of aerosol sources, including secondary aerosol formation and open burning emissions, were identified. The authors also compared aerosol compositions measured by different PM2.5 samplers, and argued that the results were not always comparable. The methodologies and interpretations were generally reliable, and the conclusions provided implications for future studies on aerosol observation and source apportionment. I agree that the manuscript is suitable to be submitted as a technical note, rather than a research article. It should be publishable if the authors could properly address the following concerns. The comments were raised during the “quick reports” stage, and are now posted for open discussion.

Line 23-25. Tone down the statement. In the abstract, it is better to say that K+ and brown carbon results should be compared or integrated with caution across studies using different PM_2.5 samplers.

Lines 40-42. Clarify that the statements are for chemical transport models.

Line 96. Re-write it as: …efforts on the exploration of PM2.5 sources…

Line 101. Is the abbreviation necessary?

Line 108-111. The sentence is too long.

Section 2.2. To my understanding, the reason for using transmittance correction is to link EC and ATN. This point should be clearly explained.

Line 130. Add “typically” before “with a linear dependence”.

Line 191. Termed as?

Figure 2. Define “ref.” appeared in the figure.

Line 195. I guess “Group-R” was missing.

Line 213. Changing “these samples” to “the targeted samples” would make the sentence clearer.

Line 216. Add “typically considered” before “soluble”.

Line 264. Remove “distinct”.

As can be seen from Figure 5b, after excluding the two highlighted samples shown by the arrows, the overestimation of BC mass by EC-untreated seemed more or less evident for the other HV samples with high sulfate loadings. However, I agree that such overestimations could be considered insignificant, since they did not disturb the linear dependence of ATN on EC-untreated shown in Figure 5a. Thus, the following changes are required: Figure 5 caption and the main text, define the two distinct samples as outliers; Line 337, change “apparent” to “significant”; Line 376, change “considerable” to “significant”.

Lines 396-398. Confirm whether all the events occurred in the spring. If some of them occurred in winter, I am afraid that it is not robust enough to attribute the events to dust.

Lines 400-401. The statement needs to be refined. Based on the available results, it is more proper to say the impact performances were not exactly the same for the two samplers, and some large particles were more effectively collected by one of them. Lines 413-415 and the conclusions have the same problem.

Lines 444-449. The statements were difficult to follow. Re-organize them.

Review of Cheng et  al. Technical note: Towards a stronger observational support for haze pollution control by  interpreting carbonaceous aerosol results derived from different measurement approaches

The manuscript by Cheng et al presents a detailed study in the measurement of carbonaceous aerosols by thermal-optical method. The authors put in a great deal of efforts in interpreting the experimental results. The analysis is generally sound and original. I support publication after my following comments are addressed.

My main suggestion for the authors to consider is that it would be very helpful for the readers to better understand the discussion related to different scenarios by showing some thermograms of the paired samples, treated and untreated, with high/low sulfate. For example, it is not clear to me whether OC still presents in the extracted samples. Relevant information are scattered throughout the paper and therefore difficult to piece together.

It would also be nice to include some discussion in the conclusion on how various results from this study can better inform the decision-making regarding haze pollution control strategy in the Northeastern China.

My other specific comments are listed below:

Line 24: it’s not clear what the authors mean by “not directly comparable”; suggest brief clarification here.

Line 47: giving rise to -> producing

Line 61: suggest to elaborate on the different techniques for EC measurements

Line 70: [EC] survives to -> I think you are trying to say that EC “evolves from the filter at [a higher temperature than OC]?

Line 113: 00:00-00:00 sampling for low volume filters?

Line 116: do you mean the high particle loading would saturate the detection of OC/EC analyzer? What is the upper detection limit of the analyzer?

Figure 1. How is TC for the methanol extracted samples in Figure 1 calculated? Also are the scatters in the lower end of TC mostly from the extracted samples? What is the uncertainty introduced by extraction?

Figure 2. Blue circles in 2a are not properly labeled.

Line 215-217: Have you done any experiment with water-extraction, since sulfate should be soluble in water and removed from the filters?

Line 414: more or less distributed on -> associated with