The comments have been uploaded in the form of a supplement:

https://egusphere.copernicus.org/preprints/2025/egusphere-2025-3254/egusphere-2025-3254-RC1-supplement.pdf

Qi et al. present valuable in-situ vertical measurements of carbonaceous aerosols (BC and UVPM) using a tethered balloon platform over the Loess Plateau — a region with limited high-resolution vertical data. The work aims to link thermodynamic and dynamic processes (e.g., potential temperature, turbulence, wind profiles) with vertical distributions of carbonaceous aerosols. This is scientifically interesting and regionally important, especially for understanding aerosol–boundary-layer feedbacks in complex terrain. However, this manuscript is not well organized, and several places need major revision. Please see my comments below for details. Moreover, this manuscript is more like a measurement report than a research article to me. I will leave this to the editor to decide whether it should be changed to a measurement report or not.

Major comments:

1. The carbonaceous aerosol mass concentration measurements are questionable. There are a few major issues as follows:
   1. MicroAeth MA350 is a light absorption measurement instrument. It does not directly measure the mass concentration of BC and BrC, but the equivalent BC (eBC) mass concentration. It measures the light absorption coefficients and uses predefined MAC at each wavelength to estimate the mass concentration of BC and BrC. Due to the highly variable MAC for BC and BrC, the predefined MAC values can lead to significant uncertainties in the mass concentration of light-absorbing aerosols. Thus, the mass concentration reported by MA350 should be used qualitatively, and eBC should be used instead of BC in the manuscript.
   2. When you calculate the UVPM mass, did you subtract eBC mass?
   3. Did you add a diffusion dryer in front of your MA350? If not, your data at high RH should be excluded since high RH can bias filter-based optical measurements.
   4. Did you apply any corrections to your results?
2. Your source apportionment part is also very confusing. You need to provide more details (e.g., how long was your back trajectory, what is each line in Fig. 9? Are there any altitudes or times? What is the end time? How did you calculate PSCF and CWT? How did you get the source information). All of this information should be provided.
3. You need to provide more details about your TBS flights. What was your flight pattern? You should show your results as altitude vs times (See an example as Figure 2 in “Vertical Gradient of Size-Resolved Aerosol Compositions over the Arctic Reveals Cloud Processed Aerosol in-Cloud and above Cloud”). It is very difficult for me to understand your results without seeing your flight pattern.
4. Since the number of your measurements is still within a reasonable amount, I suggest adding individual flight results to SI.
5. Could you provide details about how you combined and average flights that started from the same hours?
6. It is not clear to me what threshold you used for PBL height, and why you got different PBL heights for the two methods, and which one I should rely on.

General comments:

1. Your Introduction misses recent TBS work from the Atmospheric Radiation Measurement (ARM).
2. L40-L42, “OC encompasses … (VOCs).” POC can come from other sources, like vehicle emissions, and SOC can be formed from dark aging.
3. AAE is Absorption Angstrom Exponent, not Angstrom Absorption Exponent.
4. Figures S3 and S4, and Figure 2. There are many altitudes showing 0 ug m-3 eBC. Could you explain why?
5. L290-L292, “The results indicate … mean profile.” It seems to me that only 5 am, 20:00, and 23:00 show acceptable similarities. Thus, I am unsure if you can combine others.
6. Figure 2. I did not see red and blue shaded areas.
7. L302-305, “A comparative analysis … smaller differences.” Have you done any statistical tests? Why are there no IRBC at high altitudes for 5:00, 11:00, and 20:00? Why do 8:00 and 11:00 not agree with your argument?
8. L309-L313, “There, in a … Zhao et al., 2024).” I don’t think your data supports this since I did not see much increase in UVPM mass, but I did see more IR BC mass from 20:00-23:00. Moreover, I saw a significant reduction of both IR BC and UVPM at 5:00 compared with 23:00. Please justify this.
9. L330-L331, “To better … distinct features.” Could you explain how you classified those profiles? Just based on your observation, or used some statistical model?
10. Figure 3. Is the black line represent the potential temperature? If yes, please match the color of the line and that of the upper x-axis text, or define it in your legend.
11. L360-362, “The AAE … Figure S7.” Your discussion of AAE is unclear to me. How did you separate BC from other light-absorbing aerosols? Or is your AAE indeed the AAE for all aerosols? Please clarify that.
12. L364-366, “We further … (Figure 4).” It is not clear to me how you defined events based on AAE. Is that based on the literature results? If so, please provide references. Otherwise, please explain how you did that.
13. L367-368, “Likewise, … diesel contributions.” Which one is a diesel emission event? The vehicle emission line? If so, did you include gasoline vehicle emissions? How did you identify that event?
14. L368-370, “Under heavy … vapor aloft.” I do not trust your measurements under heavy fog since high RH biases MA350 measurements.
15. 370-373, “Hence, … profile.” I am not quite sure where this comes from. It seems this sentence was not connected to the previous discussions.
16. L375-377, “Previous … (Figure S8)”. Please add references and the calculations you did.
17. L377-381, “An AAE_BrC … observation site.” Please add references.
18. L394-396, “From the … Shi et al., 2020).” How did you derive PBLHc? How did you get water vapor and aerosols? Where are your PBLHc results?
19. L 432-434, “At 14:00 … boundary-layer-height.” It is unclear to me since your PBLH is below 200m.
20. Figure 5, I don’t see PBLH (Parcel) dash lines in 5:00, 8:00, 20:00, and 23:00. Please explain.
21. L462-465, “It shows that … receptor site.” Please explain this in more detail, as the air masses in general originated from high altitudes and did not exhibit any interaction with lower emissions in the surrounding urban areas.
22. 5-468, “Trajectory-cluster … ” Fig. S9 shows numerous air masses originating from Shanxi and Sichuan. Why don't you have those in your sources analysis? What are the color bar and color lines? How did you do the cluster analysis?
23. Figure 6. The color bar title is confusing since it is WPSCF, neither PSCF nor CWT.
24. L482-484, “Overall, observation site.” Your CPF results come out in the next section. You haven't discussed that yet, so how can you make the comparison?
25. Figure 7. What is the color bar? Did you plot a similar figure for eBC?
26. Figure 8. Please change the x-axis ticks to time only. You don't need to show year, month, and day. How did you calculate each arrow? Averaged by how many altitudes or time? Please also label the boundary layer height. Your boundary layer was low that day. What are the lowest altitudes your lidar can measure confidently?