General comments:

This is an interesting piece of lab and field study documenting the emission of stable carbon isotope composition of biomass burning emissions from African savanna plant species. It is known that the composition of stable carbon isotopes differs markedly between C3 and C4 plants and consequently their combustion products will have different stable isotope ratios. This information can be useful for distinguishing the sources or characteristics of biomass burning events that contribute to atmospheric pollution episodes.

I have no major comments though I ask the authors to check the manuscript thoroughly for typos and consistency.

Specific comments:

Throughout manuscript: Use either Fig. or Figure for consistency.

P9L26: “weighted average (WA)” should be given here. The abbreviation is given twice later in the manuscript.

P11L7: Spell out RMSE here.

P11L26-L27: It is not clear to me what these sentences mean to say. Do you mean “As a consequence, δ¹³C signatures of CH₄ and OC emitted by the combustion of C3 and C4 plants are much closer than the difference in the signatures of the fuel.”?

P12L2: Fig. 2f should be Fig. 3f.

P12L12: Fig. 4b and the legend do not have the hatched red bars. NMHC is in red.

P12L17-18: What is depleted? Please complete the sentence.

P12L27-28: Define EDS and LDS here.

P14L23: “savan na” should be “savanna”.

P15L1: “BB burning” should “BB”.

P16L13: This is not clear from Fig. 5 to me. Better explanation of the figure is necessary here.

Literature: Please check the formatting of the references thoroughly.

Table 3: Where does -30.82 in row “Woodland Savanna/LDS/δ¹³C” and column “Shrubs” come from? There is no number in %C_fuel in the table. This needs to be explained in the main manuscript.

Stable carbon isotopes in biomass burning (BB) emissions can be used to trace the contribution of C3 plants and C4 plants to various combustion products. However, isotopic fractionation of the emitted carbon compared to the burnt fuel is unknow or uncertain due to lack of the measurements. They studied a series of laboratory fire experiments and measured stable carbon isotope signatures in the pre-fire fuels and post-fire residual char as well as in the CO2, CO, CH4, OC and EC. The isotope fractionation found this study is very important for better estimate C3:C4 ratios in the isotope-based studies.

Major concerns:

Explanation of 13C-enriched in CO should be given.

The explanation of differences of 13C fractionation in C3 and C4 should be added. Is it due to fuel or combustion condition?

What is the reason for slightly more depleted EC compared to the previous studies?

Please estimate the C3 and C4 ratio by considering different fractionation occurring in the different processes for different fuels.