Size-resolved composition and morphology of particulate matter during the southwest monsoon in Metro Manila, Philippines

Cruz, Melliza Templonuevo; Bañaga, Paola Angela; Betito, Grace; Braun, Rachel A.; Stahl, Connor; Aghdam, Mojtaba Azadi; Cambaliza, Maria Obiminda; Dadashazar, Hossein; Hilario, Miguel Ricardo; Lorenzo, Genevieve Rose; Ma, Lin; MacDonald, Alexander B.; Pabroa, Preciosa Corazon; Yee, John Robin; Simpas, James Bernard; Sorooshian, Armin

doi:https://doi.org/10.5194/acp-19-10675-2019

Articles | Volume 19, issue 16

https://doi.org/10.5194/acp-19-10675-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

Cloud, Aerosol and Monsoon Processes Philippines Experiment...

https://doi.org/10.5194/acp-19-10675-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 19, issue 16

Research article

|

23 Aug 2019

Research article |

| 23 Aug 2019

Size-resolved composition and morphology of particulate matter during the southwest monsoon in Metro Manila, Philippines

Melliza Templonuevo Cruz, Paola Angela Bañaga, Grace Betito, Rachel A. Braun, Connor Stahl, Mojtaba Azadi Aghdam, Maria Obiminda Cambaliza, Hossein Dadashazar, Miguel Ricardo Hilario, Genevieve Rose Lorenzo, Lin Ma, Alexander B. MacDonald, Preciosa Corazon Pabroa, John Robin Yee, James Bernard Simpas, and Armin Sorooshian

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Final revised paper (published on 23 Aug 2019)
Supplement to the final revised paper
Preprint (discussion started on 12 Apr 2019)
Supplement to the preprint

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC1: 'Interactive comment of “Size-resolved Composition and Morphology of Particulate Matter During the Southwest Monsoon in Metro Manila, Philippines”', Anonymous Referee #1, 11 May 2019
- AC1: 'Authors' response to reviewers' comments', Melliza Cruz, 17 Jun 2019
  - AC3: 'Marked-up manuscript version', Melliza Cruz, 23 Jun 2019
RC2: 'Reviewer Comments', Anonymous Referee #2, 14 Jun 2019
- AC2: 'Authors' response to RC2 comments', Melliza Cruz, 23 Jun 2019

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Melliza Cruz on behalf of the Authors (25 Jun 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (26 Jun 2019) by Patrick Chuang

RR by Anonymous Referee #1 (02 Jul 2019)

Suggestions for revision or reasons for rejection

The authors have generally addressed most of the concerns raised in the review. They have moderated their speculation on the representativeness of the single BC measurement adequately. The only remaining comment I have is regarding their discussion of the updated aged aerosol factor.

Section 3.3.1 and the conclusion in section 4 have been updated to re-characterize the first PMF factor as "Aged Aerosol" with less emphasis on transport from distant regions. The intent was to indicate some contributions from distant sources are still discernible among the larger influence due to local or regional sources. While not critical, I had one suggestion to improve clarity in the description in section 3.3.1.
The second paragraph now states:
"This PMF source factor is referred to as Aged Aerosol owing to its characteristic species being linked to secondary particle formation from emissions of local and regional sources. Examples include MSA and DMA being secondarily produced from ocean-derived gaseous emissions (e.g., Sorooshian et al., 2009), and K stemming from biomass burning emissions from upwind regions such as Sumatra and Borneo (Xian et al., 2013)."
The first sentence implies local and regional sources are the main characteristic of the factor. The second sentence then states example include ... MSA, DMA, and K... These are examples of distant transport, not local and regional sources.
The authors may wish to add an additional clarification that in addition to these primary components of the factor, some species from more distant sources were detectable, such as ... the examples.

In addition, in the conclusion in section 4 they retain two findings:
"The dominant contribution of Aged aerosols to water-soluble mass contradicts two expectations: (i) locally-produced sources in polluted cities should drown out the signal of transported aerosols, and (ii) the signal of transported aerosols should be significantly reduced due to scavenging processes upwind of the measurement site."
The first finding follows more or less from the discussion in 3.3.1, but the second does not. The discussion did not treat the extent to which distant sources were or were not reduced during transport, just that they were detectable as part of the aged PMF factor. I would also echo the comments of reviewer 2's comment here that the authors only really correlate with rainfall at the receptor, not actual meteorology along the transport route. Perhaps the idea behind (ii) should instead be stated as a question for future work in the subsequent paragraphs rather than a finding here.

One last additional specific suggestion:
Section 2.1:
"Trajectory calculations were started at 00, 06, 12, and 18 hours in MO at the height of the MOUDI inlet (~ 12 m above ground level) using meteorological files from the NCEP/NCAR Reanalysis dataset."

While not critical, I typically directly state the HYSPLIT receptor height used to run the model (e.g. HYSPLIT backtrajectories used model run heights of 100 m AGL... or something similar) as actual ground level and ground level in HYSPLIT model datasets often to not agree, so giving the receptor height used is often useful for the purposes of repeatability or comparison by others.

Lastly, I believe Fig 9 still has a reference to "Aged/Transported Aerosol" rather than "Aged Aerosol"

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ED: Publish subject to minor revisions (review by editor) (15 Jul 2019) by Patrick Chuang

AR by Melliza Cruz on behalf of the Authors (17 Jul 2019) Author's response Manuscript

ED: Publish as is (18 Jul 2019) by Patrick Chuang

AR by Melliza Cruz on behalf of the Authors (19 Jul 2019) Author's response Manuscript

Post-review adjustments

AA: Author's adjustment | EA: Editor approval

AA by Melliza Cruz on behalf of the Authors (12 Aug 2019) Author's adjustment Manuscript

EA: Adjustments approved (15 Aug 2019) by Patrick Chuang

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Short summary

This study is the first to report size-resolved PM mass and composition in metro Manila, Philippines. The results, which focus on the southwest monsoon season (SWM), are important with regard to understanding the competition between local sources and long-range transport, characterizing the properties of aerosol impacted by both aqueous processing and wet scavenging, and providing contextual data for comparison with other monsoonal regions and coastal megacities.