This paper reported the different mixing states of two amine-containing single particles, and discussed their different formation processes and influencing factors. The results showed the ambient RH was the major reason for the increase of TMA-containing particles, while the formation and influencing factors for DEA-containing particles were more complicated due to the enrichment of secondary organics. The accumulation of nitrate and organic nitrogen species in DEA-containing particles were explained as the nighttime production of particulate DEA via reactions with gaseous HNO3 and/or particulate nitrate. The different mixing states of TMA and DEA with sulfate, nitrate and ammonium were investigated, which implied that particulate DEA existed both as nitrate and sulfate aminium salts, while the particulate TMA primarily presented as nitrate aminium salt.

Since most of the field observations did not distinguish between the different behaviors of each type of amine molecule under the same ambient influencing factors, these results and conclusions based on single particle analysis are quite interesting, which shows the different fates and formation processes of two particulate amines. Given the substantial roles of amines in new particle formation and contributions to the SOA mass, the distinct mixing states and influencing factors of amine-containing particles are of great significance to reveal the formation and evolution processes of bulk OA. Overall, this manuscript is well written and results are interesting with novelty. I recommend this manuscript should be accepted for publication with one substantial revision.

In the introduction part.

I asked the authors consider why your method is suitable to do this work. For mixing state of individual particles, some scientists used the electron microscope to observe very good mixing state of inorganic and organic. However, there is no ability to obtain the amine species in organic compounds. Then the SPAMS not only can get the organic compounds of single organic particles, but they can specifically distinguish the amines. Therefore, the authors can find some related studies for this part.

Here I also feel that the authors need to tell us why you select the Nanjing city as the sampling site. In the introduction particle, you might tell us what the sampling site is suitable. Then you conducted the field campaign. Seemly, the authors did not give us strong reason for this point.

In the method part, I am interesting with the cut off size of aerosol particles in the HR-SPAMS because the study work is related with the new particle formation. I didn’t noticed what size range of particles were analyzed in the SPAMS

I might ask the authors to improve the English writing as below:

1. Line 58: “Further” should be “Furthermore”.
2. Line 111-113: references should be cited here.
3. Line 113: “(NO3 radicals, OH radicals, and ozone)” should be put in the right place.
4. Line 176: “three portions” should be “three parts”.
5. Line 180: “delayed extraction technology” was not clearly described here, the authors should give more details about this technology.
6. L236, delete the should
7. L240 Change “are presented in Figure 2” to (Figure 2)
8. L257 deleted the should. I might ask the authors carefully check the English. There are many “should” before the have been
9. L267, deleted the ambient
10. Line 283: “Generally, TMA- and DEA-containing particles both contained amine marker ions, as well as organic fragments”. The amine marker ions mentioned here were redundant since these single particles were selected based on the presence of amine markers.
11. Line 393: The upper axis in Figure 10 was not adequately presented.
12. Line 412: “the new Raʹ was reduced” should be “the new Raʹ reduced”.

Review of “Diverse mixing states of amine-containing single particles in Nanjing, China”

This article describes mixing state information for amine-containing particles derived exclusively using a single particle mass spectrometer at a sampling site in Nanjing. TMA and DEA were found to exhibit differing chemical mixing states, particularly with respect to oxidized organic and sulfate content. DEA-containing particles are proposed to be more acidic than TMA-containing particles based on the SPAMS peak area data for ammonium/aminium ions and sulfate/nitrate. The dependence of enhanced particulate TMA formation upon ambient RH has been demonstrated by others previously as cited in the article. Although not particularly novel, the article provides some new information on amine mixing state for this location. The text would benefit from a discussion of the drawbacks of single particle mass spectrometry when attempting quantitative or semiquantitative analyses (such as the acidity calculations). A discussion of the likely sources of gas phase TMA and DEA in the region would also be helpful. Do the back trajectories help to inform the dominant sources of TMA vs DEA?

The abstract should be reduced in length.

Line 94: Use the word temperature

Line 102: rewrite

Line 113: rewrite, the species in parentheses are not amines

Line 170: what flow rate?

Line 206 “marker”

Line 252: Explain for readers why vehicle exhaust is expected to drive TMA particle formation

Figure 10: It is difficult to distinguish the red and orange lines in this figure