Zhang et al. used advanced mass spectrometry tools to measure the primary organic aerosol emitted from burning a variety of biomass fuels and plastic. They reported emission factors of gases and organic aerosol from burning these fuels, and used EESI-ToF measurement to identify unique tracers for different fuels with solid statistical analysis. The very new instrument, EESI-ToF, is used to characterize biomass burning particulate matter for the first time. Given the expanding use of EESI-ToF by the community, I think this work fits the scope of ACP. The manuscript is very clearly written. I recommend this work be published after some minor changes. I have the following comments for the authors to consider.

Line 21 in the abstract: From the main text, I found out that the organic gases were measured by a total hydrocarbon analyzer. However, when reading the abstract, I thought that they were measured by AMS or EESI. I would suggest the authors talk about how the hydrocarbon gases were measured before reporting these numbers.

Line 25 in the abstract: I don’t fully understand what this sentence means. The authors may want to rewrite it.

Line 112: Does “THC” here and in Equation 2 include methane?

Line 115&117: The mass resolution of the AMS instruments can be documented here. Same for the EESI-ToF below.

Line 138: In Equation 1, as I understand, MassX is the mass flux to the detector, and the authors are not attempting to quantify the compounds. Did the authors assume that all the compounds have the same response factor when making Figure 3?

Line 154: Would be great to document the (average) densities of aerosol in Table 1 or Table S1.

Line 204: The CHON ions are not included in Figure 1. Is it because they are negligible? Were they fitted in Pika?

Line 206: If the ions in the CxHyOz family in the plastic burning spectrum are coming from burning other fuels, then are PM, OM, and BC emission factors reported for burning plastic bags still reliable? Also, did the authors see CxHyOz in all four plastic bag burning experiments?

Line 219: What is the “f₆₀ filter”? Is it 0.003?

Line 229: It might be good to label the PAH ions in the mass spectra (Figure S2).

Line 230 and 231: The authors may want to double-check what the ion with m/z 239 is. It should not be the parent ion of a hydrocarbon. Also, is the molecular formula of methylbenzofluoranthene C19H12? I think it should be C20H14. I am also curious whether the authors found a hint of retene in the AMS mass spectra because retene is usually a very abundant PAH emitted from burning conifers. It could have fragmented into smaller ions given its branched structure.

Line 262: Compounds with 18-20 carbon atoms could be resin acids (or their decomposition products in biomass burning), which are abundant in conifers. Also, in Line 286, I am curious that did the authors see emission of dehydroabietic acid (C20H28O2) from burning coniferous fuels?

Line 298: How is the correlation coefficient calculated? The authors may want to provide more details.

Line 409: I am convinced by this analysis that the p-value and FC methods can select tracer compounds from different biomass burning fuels very efficiently. However, in source apportionment studies, there are usually non-biomass burning PM sources. I would suggest that the authors compare the spectra of the biomass burning POA with OA from other common sources in their future study or verify these tracers in future field campaigns to make sure they are exclusively from biomass burning.

Minor Comments

Line 251-253: This seems to be an unfinished sentence.

Line 257: A redundant “%” should be removed.

Line 696: “markers denote”

General comments:

This study estimated the emission factors and characterized the POA with AMS and EESI-TOF from a variety of solid fuels. This topic is interesting and the experiment is well-designed.

However, some typos and misunderstandings were found. More necessary discussions and details are suggested to be provided. The authors should provide more convincing results. I recommend a major revision of this manuscript.

Major concerns

• The abstract part does not stress the importance of this manuscript, only emphasizing that OA is important, biomass burning is the common source of OA, and EESI-TOF is powerful. What is the urgency of measuring OA from the molecular level? What is the breakthrough and highlight of this work?
• Please add some instrument comparisons in the introduction part. Why is EESI-TOF important? We admit that less decomposition or fragmentation is observed in EESI-TOF measurement, however, the homolog speciation could not be achieved.
• Is burning plastic bags  really important? Please add more details or figures to illustrate this.
• The standard deviation of CO, and THC of straw burning and plastic bag burning is extremely high. Please specify. Note that other pollutants are not varied significantly.
• Line 229- 239: please add more detail or discussion about WHY PAHs are so different among samples. Does the material or burning styles shape the emission pattern?
• Line 264-267, add more uncertainty analysis to the quantitative or qualitative measurement.
• Line 273, how could the authors be sure that C6H10O5 (m/z 162.0523) is levoglucosan (or similar dehydrated sugars)? Is there any GC-MS measurement?
• Part 3.3, Levoglucosan is not a good marker. However, C16H32O2 is also not a good marker. Note that cooking emissions could also result in emissions of these so-called "markers" in this work. Please add more details.
• Line 370: how could the authors be convinced that most of these markers are reported for the first time in POA emissions from the studied fuels? The investigation of pyrolysis of lignins has lots of results related to sugars, alcohols, and benzaldehydes.
• Please add more atmospheric implications in the conclusion part. The current paragraphs are only the common conclusions stated by the authors before.

Minor comments

• The abstract part is not transparent and brief. See line 17 – 20, I recommend cutting this sentence into two separate sections.
• Line 42:45: "… Southeast Asia… developing regions,…India", Please rewrite these sentences, as these regions are involved with each other.
• Line 117: high-resolution time-of-flight AMS (HTOF-AMS)? OR HR-TOF?
• Line 171, why is p<0.1 chosen?
• Line 692, static p?

The study utilized two methods, namely the aerosol mass spectrometer (AMS) and the extractive electrospray ionization time-of-flight mass spectrometer (EESI-TOF), to investigate the molecular composition of primary organic aerosol derived from various solid waste sources. The study also reported emission factors and presented spectra obtained from the AMS and EESI-TOF instruments. While the article is well-written, there are some areas that require improvement before publication.

1. The title and abstract/keywords suggest a desire for insights into the molecular-level composition and markers. Although Section 3.4 briefly discusses individual markers, the discussion seems disconnected from the figures and tables and is not adequately reflected in the abstract and conclusion. Enhancing the presentation and discussion of these markers would make the work more captivating.
2. Most of the figures predominantly focus on the overall composition in a statistical manner. It would be helpful if the authors elaborate on whether they consider the composition or individual molecules more important for source apportionment. This clarification would enrich the paper.
3. Although the introduction mentions the possibility of using Positive Matrix Factorization (PMF) for data analysis, it was not employed in this study. Are there any plans to utilize PMF for analyzing this dataset? This aspect could be addressed to provide a clearer understanding.
4. On page 6, line 204, the reasoning for excluding the mass spectrum of plastic bags burning is not convincing. The statement suggests that the observed CxHyOz family in the spectrum (23%) is more likely due to emissions remaining in the tubing from other fuels rather than from the plastic bags themselves, given that polyethylene is their main component. It would be valuable to include the results of plastic bag burning in the main figures and provide further explanation regarding the expected products from burning plastic bags.
5. On page 11, line 402, the statement "the markers identified by the AMS have greater replicability and by EESI-TOF are more distinctive, thus providing an important reference for the source apportionment" lacks clarity. Please rephrase this sentence to enhance its meaning.

The article by Jun Zhang et al. describes the emissions of biomass burning using different devices both on molecular level and on bulk. The emission factors and composition of emissions are shown to depend on the burned fuel and some marker compounds are identified. Article is well written and easy to read and follow. The information provided in the article is important for scientific community and the in my opinion the article should be accepted after revision. I have few comments mainly intending to clarify some aspects of the manuscript:

1. The results section is referring to PM. Please give the corresponding size class, PM1? PM0.5? is it always always same, from the SMPS, not AMS? I think it is fine if you add a sentence about this to experimental and then continue using PM abbreviation.
2. Please describe the holding tank and its role in more detail. Why it was used and what was the impact on PM?
3. Fig S1. maybe replace Dekati with Dekati Ejector
4. Line 204: “The mass spectrum of plastic bags burning is not shown because considerable CxHyOz family was observed (23%), but it is more likely from the emission remaining in the tubing of other fuels than from the plastic bags given the fact that polyethylene is the main component of it.” was this only affecting AMS results or are all plastic bag burning results suffering from this? did you measure blank values to ensure this same phenomenon was not affecting other results also?
5. Line 199: how the PM/OM/BC Emission factors compare with literature values? are the literature available for e.g. plastic bags?
6. Are the terms f44/f60/fxx etc explained somewhere? I may have missed this
7. Authors are using terms OA, OM, OC and POA for the organic fraction. Maybe you could clarify what is the difference between them.