The manuscript entitled "Measurement report: Characteristics of aminiums in PM_2.5 during winter clean and polluted episodes in China: aminium outbreak and its constraint" presents the pollution characteristics of amine organic compounds in PM_2.5 in 11 regions of China. It focuses on the comparative analysis of clean and polluted days. While the study has certain scientific significance, the analysis and discussion part of the study is not in-depth enough, and there are still some problems that the author needs to further answer or improve.

Q1: The English writing of the article required modification prior to publication. The text contained numerous descriptions that were overly complex, rendering them opaque and indirect. For example, Lines 175-179.

Q2: The whole study only analyzes and explores the correlation and ratio relationship between regions and components. The reasons for the clarification need to be further demonstrated. There is no analysis of the mechanism relationship between amines and particulate matter, and much experimental literature has been studied.

Q3: The article only stays at the level of analyzing phenomena. The organic amines on the filter membrane are still aged particulate organic matter. The results are not accurate enough for source estimation using correlation and ratio.

Q4: The article mentions that the XA and BJ sampling sites differ more than others. The reason should be compared and analyzed to recent 2-3 years of literature on the source of air pollution. And while Figure 5 of the article only shows the correlation of NH₄⁺ with NO₃^—, SO₄^2-, and total organic acids in XA and BJ, how does a clean day compare to a polluted day?

Q5: Line 20-122, please accurately describe the sampling times for particulate filters.

Q6: Line 250-251: Figure 4 does not reflect the different seasons, please correct this.

Q7: Line 251-257: The conclusions of the presentation in this paragraph are comparable to those of the previous study. It would be beneficial to include the data from the previous research results in a comparison in the figure.

Q8: Line 311-312: This passage has illustrated the inadequacy of traditional correlation analysis to account for research discrepancies. Moreover, the subsequent conclusions have not been further explored in terms of new methods.

Q9: Line 319-322: The text is ambiguous. What is the author's intention here?

Q10: Line 359-360: Is it accurate to discuss atmospheric oxidation here and compare it with the average values?  It is suggested that the changing trend of amine pollution level and atmospheric oxidation level should be further analyzed.

Q11: Line 394-402: This paragraph is analyzed using the ratio relationship between total amines and ammonium salts. Is there a literature reference for this conclusion? Please add literature for further clarification.

Q12: This paper discusses that although the component characteristics of TY and GZ areas are similar, there are great differences according to the scatter diagram. What are the reasons for the differences?

This work presents the measurements of aminiums in PM_2.5 collected from 11 cities in China during winter, and compares their characteristics and chemistry between the clean and polluted periods to investigate the key factors influencing the aminium outbreak during the polluted periods. The authors suggested that the competitive uptake of ammonia versus amines on acidic aerosols and/or the displacement of aminiums by ammonia in ambient aerosols are the key to limiting aminium outbreaks. I find this to be a useful contribution to the literature to advance knowledge about amines. Indeed, amines (/aminiums) are important in many aspects of atmospheric chemistry. These datasets are valuable for amine-related chemistry in the atmosphere. In general, the paper is well written, and this reviewer recommends its publication after addressing the following minor comments.

Specific comments:

• The aliphatic amines are typically in the gas-phase, thus their presence in aerosol particles should be attributable to acid-base chemistry and/or other processes. This implies that all aminiums reported here were predominantly formed through secondary processes. In discussing sources, you refer to the sources of gas-phase amines. It is important to highlight that these gas-phase amines from diverse sources are mainly partitioned into the particle phase through secondary processes. This should be clear.
• Line 232: Significant figures should be unified.
• RH is another important factor affecting the formation of aliphatic aminiums in addition to acidity. This should be considered.
• Line 301: Please consider using a more suitable word instead of “roughly”.
• Lines 363‒366: Please rephrase the sentence.
• Regarding the sensitivity analysis of the aminiums/ammonium ratio to ammonium changes, the results presented here are very intuitive and interesting. Have similar comparisons been made in previous studies? Alternatively, can the datasets be compared with previous observations?
• Lines 433‒435: Please rephrase this part. For example, “The concentrations, compositions, and temporal and spatial variations of aminiums in PM2.5 in 11 different Chinese cities during the winter were systematically investigated to reveal the key factors affecting the aminium outbreak during the polluted days”
• The author has proposed some meaningful conclusions based on field observation data, such as “the competitive uptake of ammonia against amines on acidic aerosols in the ambient atmosphere in XA and BJ”. I know that the atmospheric environment in the real world is very complex, so the author should point out in the article that further laboratory validation experiments for this conclusion or long-term observation studies in high ammonia and low amine environments are necessary in future research.
• Lines 473‒477: The author should point out that the occurrence of this situation may lead to an insignificant correlation between aminiums and indicators in the particle phase.