Wang et al. “The pathway of aerosol direct effects impact on secondary inorganic aerosol formation”

This short and concise study investigates the different pathways of aerosol direct effects impact on sedondary inorganic aerosol formation between winter and summer. The results show that solar radiation is the restricting factor in winter, and the formation of sulfate is sensitive to the perturbation of solar radiation. While in summer, availability of gaseous precursors primarily dictates the levels of secondary aerosol concentrations. The findings are valuable and interesting to the science community. Thus, I would like to recommend its acceptance for publication after necessary minor revisions.

General comments

There are some writing issues with several figured out in the following comments.

Line 37-40, aerosol effects on regional weather is not due to their spatio-temporal distribution, but due to the radiative effect or impact on cloud properties. In addition, three studies about the aerosol impacts on regional weather are suggested here, Sun and Zhao (2021, doi: 10.5194/acp-21-16555-2021) for aerosol impacts on precipitation time, Zhao et al. (2018, 2020, doi: 10.1093/nsr/nwz184, doi: 10.1029/2018GL079427) for aerosol impacts on weather over Tibetan Plateau and western pacific.

Line 40, What do the authors mean “aerosol direct effect on air pollutants”? The authors might provide a defidition for the aeroosl direct effects (ADE).

Line 43-44, this is true, which could further reduce the planetary boundary layer heigth and near surface wind speed, resulting in further heavier aerosol pollution, as indicated by Yang et al. (2016, doi:10.1002/2015JD024645).

Line 44-45, regarding the aerosol solar radiative cooling effect, a few references might be helpful, such as Yang et al. (2016,2018, doi:10.1002/2016JD024938, doi:10.1016/j.atmosres.2018.04.029). In addition, it might be not necessary to indicate the values here since they should vary with time and location.

Line 52, it might be useful to define “secondary aerosol” first. Also, personally, I would more prefer using “seondary formed aerosol”.

Line 55, “illustrate” should be “illustrated”?

Line 57, “show” should be “showed”?

Line 59, “has” -> “have”

Line 69-74, this should be the air quality status of the past, not current. However, as indicated by Fan et al. (2020, doi: 10.1016/j.atmosenv.2019.117066) and Zhang et al. (2020, doi: 10.1007/s13143-019-00125-w), the air quality in China has improved significantly owing to the strict control acts in China. This fact should be acknowledged.

Line 81, it should by “in Xing et al. (2017)”

Line 87-88, I belive the “other physical processes” should be more than what described here. The authors might slightly modify the description.

Line 99, what are the vertical resolutions for the two model simulations within boundary layer heigtht?

Line 101-103, How reliable are the observation data from this platform? Are there any scientific studies based on the dataset that can serve as supporting references?

Line 110, “was” -> “were”

Line 114-121, a breif description about the PA technology and IPRs is necessary for readers to understand.

Line 124-125, I wonder if these are monthly average values including days with clouds? Or simply, are these values monthly averages for clear skies? How did the authors exclude the clouds?

Line 127-129, Similarly, are the results for all skies or clear skies only?

Line 168, “raises”?

Line 176, the authors can simply describe “effective optical depths” as “optical paths” without further definition or explanation.

Line 177-178, It is not robust to say “this impact will be more significant at high tau” since it actaully depends: when tau is not too high, the diffuse increase with tau; however, when tau is large enough, the diffuse radiation will decrease with tau.

Line 179-180, This increase to 2.5 is not a common phenomenon that can be observed frequently, thus I would suggest changing “reaches to 2.5” to “reached 2.5”.

Line 189, “affect” -> “affects”

Line 198-199, I would suggest changing “The height of strongest effect is” to “The height with the strongest effect is”

Line 199, “amplify” -> “amplifies”

Line 204, “reduce” -> ‘reduces”

Line 210, local time or UTC time?

Line 218, “studies”?

Line 225, delete one “shown in” from the twos.

This manuscript presents a model-based analysis on aerosol-radiation-boundary layer interactions and feedbacks, with a focus on secondary sulfate and nitrate formation under polluted conditions. The topic is original and the paper appears scientifically sound. I have a few, mostly minor, issues to be considered before acceptance of this paper for publication.

Scientific issues:

Main main comment concerns the structure of section 3. Now there is three longish paragraph discussing sulfate formation, then two short paragraphs on oxidants and AOD, and finally something about nitrate formation. I wonder whether this is the best way of presenting the results for a reader to easily follow the discussion. Furthermore, there appears to be some unnecessary repetition of text in this section. For example, the relative roles of ADEP and ADED in forming sulfate in summer and winter is discussed in three places (lines 146-147, 159-161, 183-184).

Related to the previous comment, the authors refer to section 3.2 on lines 201 and 206, a section which does not exist. I wonder whether some earlier versions of this paper have had structure different from the current one.

The list of compounds given on line 192 certainly participate in atmospheric oxidation reactions, but not all of them (e.g. NO2 and HNO3) can be considered as oxidants. Please reword and modify this part of the text accordingly.

Essentially the same thing is stated on lines 230-231 and 235-236. Please avoid repetition. Also, I would suggest some rewording: …more complicated than its impact on primary aerosol.

Minor technical issues:

line 48: … observations…

section 2 title should read "Methods"

line 127: The PBL height …

lines 135, 137 and 138: in the near-surface layer

line 185: … effect on …

line 207: diffuse solar radiation

Figure 8 is referred to before Figure 7. Please check out that they are referred to correctly in the paragraph on lines 212-227. If necessary, change the order of figures such that they are referred to in correct numerical order.