Characteristics and degradation of organic aerosols from cooking sources based on hourly observations of organic molecular markers in urban environments

Li, Rui; Zhang, Kun; Li, Qing; Yang, Liumei; Wang, Shunyao; Liu, Zhiqiang; Zhang, Xiaojuan; Chen, Hui; Yi, Yanan; Feng, Jialiang; Wang, Qiongqiong; Huang, Ling; Wang, Wu; Wang, Yangjun; Yu, Jian Zhen; Li, Li

doi:https://doi.org/10.5194/acp-23-3065-2023

Articles | Volume 23, issue 5

https://doi.org/10.5194/acp-23-3065-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-23-3065-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 23, issue 5

Research article

|

09 Mar 2023

Research article |

| 09 Mar 2023

Characteristics and degradation of organic aerosols from cooking sources based on hourly observations of organic molecular markers in urban environments

Rui Li, Kun Zhang, Qing Li, Liumei Yang, Shunyao Wang, Zhiqiang Liu, Xiaojuan Zhang, Hui Chen, Yanan Yi, Jialiang Feng, Qiongqiong Wang, Ling Huang, Wu Wang, Yangjun Wang, Jian Zhen Yu, and Li Li

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Final revised paper (published on 09 Mar 2023)
Supplement to the final revised paper
Preprint (discussion started on 05 Sep 2022)
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Interactive discussion

Status: closed

RC1:
'Comment on acp-2022-586', Anonymous Referee #1, 13 Oct 2022

Please find comments in the attached document.

Citation: https://doi.org/10.5194/acp-2022-586-RC1
- AC1: 'Reply on RC1', Li Li, 07 Dec 2022
  
  The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-586/acp-2022-586-AC1-supplement.pdf
  
  Citation: https://doi.org/10.5194/acp-2022-586-AC1
RC2:
'Comment on acp-2022-586', Anonymous Referee #2, 18 Oct 2022

The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-586/acp-2022-586-RC2-supplement.pdf

Citation: https://doi.org/10.5194/acp-2022-586-RC2
- AC2: 'Reply on RC2', Li Li, 07 Dec 2022
  
  The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-586/acp-2022-586-AC2-supplement.pdf
  
  Citation: https://doi.org/10.5194/acp-2022-586-AC2

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

AR by Li Li on behalf of the Authors (07 Dec 2022) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (12 Dec 2022) by James Allan

RR by Anonymous Referee #3 (16 Jan 2023)

Suggestions for revision or reasons for rejection

In this study, the authors used TAG techniques to study fatty acid concentrations in the atmosphere, including saturated fatty acids, unsaturated fatty acids, and their oxidative decomposition products. The authors attribute these fatty acid species to emissions from cooking. Their higher time resolution chemical speciation with TAG represents a detailed, valuable dataset, and I appreciate their use of backward trajectories and PMF to understand chemical sources. However, I echo the previous review comments that some of the conclusions here still aren’t fully supported by the data. I can see that the authors did carefully address reviewer comments from the first round. I would suggest that the authors further soften the language in the text throughout the manuscript to account for the fact that there is significant uncertainty in the sources of the primary and secondary products observed here. This is a result of field measurements being very challenging to interpret with mixed sources contributing to any one measurement, and I think this needs to be better acknowledged and reflected in the manuscript. I think the manuscript is acceptable for publication in Atmospheric Chemistry and Physics following a careful review of how each conclusion is stated.

Introduction:
Line 51: I would be careful with this phrasing, so that you do not attribute all lung cancer to exposure to cooking fumes.
Line 62: write out “hydroxyl” and “nitrate” and then use the acronyms after you’ve defined them in words
I would consider re-organizing the introduction so that you talk about TAG methods (and why online measurements are important) after introducing cooking emissions more – so perhaps could move lines 55-69 to after lines 70-77.

Methodology:
Line 85: please be more specific about what you mean by “its main chemical constituents as well as organic markers”
Can you comment on any fatty acid losses to your instrument, i.e., in the cyclone, dryer, or denuder?

Results and discussion:
Line 164-165: It would help to list out these instruments specifically in your methods section. I would also suggest moving the paragraph where you describe each of these instruments in the SI to your main text. It is a short paragraph and it would help readers understand the measurements you took.
Axes on Figure 2 are very hard to read – can you put more space between each panel? Also your axis breaks are very small, can you make them larger? And finally, can you put a number below your axis break (not just above), so it is more clear what the values are right before and after the break?
Line 180: specify what time of day “dinner time” is
Line 183: What meteorological conditions are present in “clean” and “polluted” periods? Are there more emissions during the “polluted period” or simply different meteorological conditions?
Line 210: How did you eliminate boundary layer height? Is that what is shown in b?
Line 212: I agree, but there are also other active sources during these times, as people heat their homes and drive their vehicles to/from work, so I would be careful with this language here. I don’t think it is convincing that these are ONLY cooking emissions. The paragraph from lines 224-231 is valuable (discussing ratios of fatty acids from difference sources). Figure 4 is also valuable, depicting this information. But cooking ratios overlap so much with pretty much all other source profiles, so I think you need to be careful how much you emphasize that these are cooking derived-emissions. Also, what references are contributing to figure 4? Please cite them in the figure itself.
Line 246: Can you prove this with ozone reactivities? Linoleic acid has an extra double bond than oleic acid so it makes sense it would degrade in the atmosphere more rapidly
Figure 5 caption: Please provide more details on how this cooking source profile was determined
Line 272: should say “Figure 6"
Lube 286-290: What about primary sources of these ODPs from the ocean? I don’t think these are solely attributable to oxidation, and I suggest softening the language here.
Figure 8: The color of O3 in the legend and in the figure is different
Line 302: How can you be certain that this is just driven by oxidative decomposition, not dilution or lower emissions? The language here needs to be softened.
Line 305: How can you be certain that the ONLY sources of these two species is oleic acid ozonolysis? The language here needs to be softened to account for the other possible sources
Line 334: What about the impact of plume dilution during this time? In addition to oxidative decay?

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RR by Anonymous Referee #1 (29 Jan 2023)

ED: Publish subject to minor revisions (review by editor) (06 Feb 2023) by James Allan

AR by Li Li on behalf of the Authors (16 Feb 2023) Author's response Author's tracked changes Manuscript

ED: Publish as is (16 Feb 2023) by James Allan

AR by Li Li on behalf of the Authors (17 Feb 2023) Manuscript

Post-review adjustments

AA: Author's adjustment | EA: Editor approval

AA by Li Li on behalf of the Authors (03 Mar 2023) Author's adjustment Manuscript

EA: Adjustments approved (03 Mar 2023) by James Allan

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Short summary

Molecular markers in organic aerosol (OA) provide specific source information on PM_2.5, and the contribution of cooking emissions to OA is significant, especially in urban environments. This study investigates the variation in concentrations and oxidative degradation of fatty acids and corresponding oxidation products in ambient air, which can be a guide for the refinement of aerosol source apportionment and provide scientific support for the development of emission source control policies.