Impact of in-cloud aqueous processes on the chemical compositions and morphology of individual atmospheric aerosols

Fu, Yuzhen; Lin, Qinhao; Zhang, Guohua; Yang, Yuxiang; Yang, Yiping; Lian, Xiufeng; Peng, Long; Jiang, Feng; Bi, Xinhui; Li, Lei; Wang, Yuanyuan; Chen, Duohong; Ou, Jie; Wang, Xinming; Peng, Ping'an; Zhu, Jianxi; Sheng, Guoying

doi:https://doi.org/10.5194/acp-20-14063-2020

Articles | Volume 20, issue 22

https://doi.org/10.5194/acp-20-14063-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-20-14063-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 20, issue 22

Research article

|

20 Nov 2020

Research article |

| 20 Nov 2020

Impact of in-cloud aqueous processes on the chemical compositions and morphology of individual atmospheric aerosols

Yuzhen Fu, Qinhao Lin, Guohua Zhang, Yuxiang Yang, Yiping Yang, Xiufeng Lian, Long Peng, Feng Jiang, Xinhui Bi, Lei Li, Yuanyuan Wang, Duohong Chen, Jie Ou, Xinming Wang, Ping'an Peng, Jianxi Zhu, and Guoying Sheng

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Interactive discussion

Status: closed

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

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RC1: 'Review of Fu et al.', Anonymous Referee #1, 26 May 2020
- AC1: 'Response 1#', Guohua Zhang, 04 Aug 2020
RC2: 'Fu et al 2020', Anonymous Referee #2, 10 Jul 2020
- AC2: 'Response to referee 2#', Guohua Zhang, 04 Aug 2020

Peer-review completion

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

AR by Guohua Zhang on behalf of the Authors (04 Aug 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (24 Aug 2020) by Jason Surratt

RR by Anonymous Referee #2 (04 Sep 2020)

Suggestions for revision or reasons for rejection

General:

This paper compares single-particle measurements of particle size, composition, and morphology of in-cloud and interstitial particles collected at a rural site in China. This paper mainly comments on the role of aqueous chemistry in forming organic shells and the observation of more branched soot particles in cloud. The revision is much clearer and improved. I recommend publication after consideration of my comments.

Major Comments:

1. There are a lot of grammatical errors in this paper. I only list a few here but encourage the authors to carefully review and correct their work prior to submission.

2. I suggest that the authors provide more context for what is in the SI. For instance, a lot of the SPAMS description is in the SI. The authors need to point this out in the main text as well.

Specific Comments:
Abstract:

Line 33 and throughout the paper: “mineral” should be changed to “mineral dust”

Lines 33-34: I still have some reservations about the “aged mixture” label for the most important particle type for RES. It is a non-descript particle class. I suggest that the authors re-think this classification to appeal to a broader audience.

Line 38: I suggest that authors give a very quick definition of the Df to appeal to a broader audience.

Introduction:

1. Line 46: remove “at a certain supersaturation”

2. Line 49: change “coagulation” to “coalescence”

3. I think what is missing is some context for cloud droplet formation and evaporation cycles. I suggest describing the number of cloud/evaporation cycles aerosols go through in their lifetime and that these processes critically shape particle size, morphology, and composition with impacts on clouds and direct radiative forcing.

4. Line 68: incomplete sentence

5. Lines 81-87: make it clear what Df impacts: size? Radiative impacts?

6. Line 83: I think the authors mean aqueous processing

Methods:

1. Lines 126-127: I think the authors mean “intensity of elements including carbon and heavier elements”. As written, this would imply that they cannot detect carbon with their EDS.

2. Line 133: what are particles with rim?

3. Line 140 and throughout: change “S-rich” to “S-rich particles”

4. Line 148: please also cite [Moffet et al., 2008]

5. Line 156: are particles focused by an aerodynamic lens or nozzle inlet?

6. Line 156: the authors should clarify here that the sizing region measures the terminal velocity of the particles. These velocities are converted to vacuum aerodynamic diameter (not vacuum dynamic size) via calibration with polystyrene spheres of known size.

7. Line 158: the authors should specify that ions are separated and analyzed using a dual polarity time-of-flight mass analyzer.

8. Line 159: change “mass spectrometry” to “mass spectra”

9. Lines 159-161: please cite [Bhave et al., 2002; Gross et al., 2000]

10. Section 2.4: a lot of detail is in the SI. The authors need to at least mention that the particle analysis methods, calibration methods, and particle type characteristics can be found in the SI.

Results:

1. Lines 192: does the high abundance of aged mixture particles in the RES indicate a lot of collision/coalescence of droplets with refractory material?

2. Line 203: is an incomplete sentence

3. Lines 235-243: I suggest moving this text to section 3.4

4. Lines 249-253: The authors cannot completely rule out that larger S-OM particles were more likely to be activated based on their size alone.

5. Line 258: Please clarify this sentence. It seems that the authors are implying that they do not have OM mixed with sulfate even though they just mentioned S-OM particles.

6. Lines 268-270: this sentence needs to be rephrased. I do not understand it.

7. Lines 277-279: did the SPAMS see higher peak areas of m/z +43, which was found to be indicative of SOA and associated with high concentrations of O3 (see [X Qin et al., 2012]).

Figures

1. I suggest adding an asterisk by elements that were considered background (e.g., Si and Cu).

SI
1. Section 3: what software was used to import SPAMS spectra into Matlab? How many particles were analyzed?

2. Section 3 also needs more citations for the characterization of these particle types. I suggest citing [Denkenberger et al., 2007; X Qin et al., 2012; X Y Qin and Prather, 2006] for the EC and HMOC particle types. I suggest [Silva et al., 2000] for the dust particle type. I suggest [Gaston et al., 2011] for the sea salt particle type. I suggest [Angelino et al., 2001; Pratt et al., 2009] for the amine particle type.

References:

Angelino, S., D. T. Suess, and K. A. Prather (2001), Formation of aerosol particles from reactions of secondary and tertiary alkylamines: Characterization by aerosol time-of-flight mass spectrometry, Environ. Sci. Tech., 35(15), 3130-3138.

Bhave, P. V., J. O. Allen, B. D. Morrical, D. P. Fergenson, G. R. Cass, and K. A. Prather (2002), A field-based approach for determining ATOFMS instrument sensitivities to ammonium and nitrate, Environ. Sci. Tech., 36(22), 4868-4879.

Denkenberger, K. A., R. C. Moffet, J. C. Holecek, T. P. Rebotier, and K. A. Prather (2007), Real-time, single-particle measurements of oligomers in aged ambient aerosol particles, Environ. Sci. Tech., 41(15), 5439-5446.

Gaston, C. J., H. Furutani, S. A. Guazzotti, K. R. Coffee, T. S. Bates, P. K. Quinn, L. I. Aluwihare, B. G. Mitchell, and K. A. Prather (2011), Unique ocean-derived particles serve as a proxy for changes in ocean chemistry, J. Geophys. Res.-[Atmos.], 116, D18310, doi:18310.11029/12010JD015289.

Gross, D. S., M. E. Galli, P. J. Silva, and K. A. Prather (2000), Relative sensitivity factors for alkali metal and ammonium cations in single particle aerosol time-of-flight mass spectra, Anal. Chem., 72(2), 416-422.

Moffet, R. C., et al. (2008), Characterization of aerosols containing Zn, Pb, and Cl from an industrial region of Mexico City, Environ. Sci. Tech., 42(19), 7091-7097.

Pratt, K. A., L. E. Hatch, and K. A. Prather (2009), Seasonal volatility dependence of ambient particle phase amines, Environ. Sci. Tech., 43(14), 5276-5281.

Qin, X., K. A. Pratt, L. G. Shields, S. M. Toner, and K. A. Prather (2012), Seasonal comparisons of single-particle chemical mixing state in Riverside, CA, Atmos. Environ., 59, 587-596.

Qin, X. Y., and K. A. Prather (2006), Impact of biomass emissions on particle chemistry during the California Regional Particulate Air Quality Study, International Journal of Mass Spectrometry, 258(1-3), 142-150.

Silva, P. J., R. A. Carlin, and K. A. Prather (2000), Single particle analysis of suspended soil dust from Southern California, Atmos. Environ., 34, 1811-1820.

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RR by Anonymous Referee #1 (07 Sep 2020)

ED: Publish subject to minor revisions (review by editor) (07 Sep 2020) by Jason Surratt

AR by Guohua Zhang on behalf of the Authors (15 Sep 2020) Author's response Manuscript

ED: Publish as is (05 Oct 2020) by Jason Surratt

AR by Guohua Zhang on behalf of the Authors (06 Oct 2020)

Post-review adjustments

AA: Author's adjustment | EA: Editor approval

AA by Guohua Zhang on behalf of the Authors (12 Nov 2020) Author's adjustment Manuscript

EA: Adjustments approved (20 Nov 2020) by Jason Surratt

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Short summary

Based on the analysis of the morphology and mixing structure of the activated and unactivated particles, our results emphasize the role of in-cloud processes in the chemistry and microphysical properties of individual activated particles. Given that organic coatings may determine the particle hygroscopicity and heterogeneous chemical reactivity, the increase of OM-shelled particles upon in-cloud processes should have considerable implications for their evolution and climate impact.