The study presented here is a valuable contribution to the aerosol community. It provides optical properties, more specifically mass absorption cross section values, for three different soot-like aerosol samples. Two of the samples are based on the combustion of liquid fuels burned in a real diesel engine. The manuscript is well written and the data are well presented. I would suggest publishing it after addressing the following comments:

Scientific comments

- Provide information on the calibration of the various instruments, especially the PAX.

- The EC:TC ratio is quite different for the different samples. The larger amount of OC in some samples could affect the MAC amid coating. However, the authors do not address this issue. Please comment on this.

- It has been shown that MISG soot has an average diameter between 200-300 nm. The very different particle diameter compared to the other two samples will strongly affect the MAC values, making these results not comparable. In addition, the large size of MISG-generated soot particles is not representative of engine exhaust soot. Is the use of the MISG still justified?

- It would be interesting to see how the different absorption coefficient measurement techniques compare in terms of b_abs.

- In Table 4, it would be valuable to include the MAC values interpolated to 550 nm in addition to those already shown. This would make it easier for the reader to make comparisons with literature values.

- What is the wavelength in Figure 4? Please add it to the axis labels.

- I would recommend showing the absorption angstrom exponents measured by the MWAA.

- The conclusion section is weak. There is no discussion of the implications of the MAC values found in the study. Please improve.

- "Correction factors" are mentioned on page 16. Please elaborate. What corrections are referenced?

Typos

- Page 11, second paragraph: MISG is misspelled.

See attached PDF

Danelli et al. present a study investigating the EC/OC ratio, particle size distribution, and MAC of carbonaceous aerosols produced from the combustion of various fuels using an atmospheric simulation chamber. The experimental setup is well designed, and the results provide meaningful insights into the optical properties of combustion-derived aerosols. This study aligns with the scope of ACP as a measurement report. I recommend it for publication, provided the following comments are addressed:

1. The current title may be misleading, as not all particles investigated are derived from diesel exhaust. I suggest revising the title to better reflect the scope of the study. For example:
   
   “Investigation of Optical Properties of Carbonaceous Aerosols from the Combustion of Different Fuels Using an Atmospheric Simulation Chamber.”
2. While the study focuses on aerosol optical properties, no health-related outcomes are presented. Therefore, I suggest removing or minimizing health-related discussions in the Introduction, as they may distract from the main focus.
3. For the MISG experiments, please clarify the rationale for selecting the specific “global equivalence ratio.” Was this condition intended to replicate soot production mechanisms similar to those in diesel engines? Since the EC/OC ratio is highly sensitive to combustion stoichiometry, a justification for this choice is essential to contextualize comparisons with engine-derived emissions. Additionally, please ensure the reference “Vernocchi et al., 2022” is listed in the References, as it appears to be missing.
4. The measured particle size distributions are based on mobility diameters (SMPS). Did the authors consider the influence of particle morphology? For instance, the larger mobility diameters observed for soot generated by MISG are likely due to the aggregate structure typical of high-EC (soot-rich) particles. This morphology can significantly inflate the mobility diameter relative to the volume-equivalent diameter and should be discussed when interpreting the size data.
5. Please include the standard deviation of the EC:TC ratio in the abstract.