Secondary organic aerosol (SOA) yields from NO<sub>3</sub> radical + isoprene based on nighttime aircraft power plant plume transects

Fry, Juliane L.; Brown, Steven S.; Middlebrook, Ann M.; Edwards, Peter M.; Campuzano-Jost, Pedro; Day, Douglas A.; Jimenez, José L.; Allen, Hannah M.; Ryerson, Thomas B.; Pollack, Ilana; Graus, Martin; Warneke, Carsten; de Gouw, Joost A.; Brock, Charles A.; Gilman, Jessica; Lerner, Brian M.; Dubé, William P.; Liao, Jin; Welti, André

doi:https://doi.org/10.5194/acp-18-11663-2018

Articles | Volume 18, issue 16

https://doi.org/10.5194/acp-18-11663-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-18-11663-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 18, issue 16

Research article

|

16 Aug 2018

Research article |

| 16 Aug 2018

Secondary organic aerosol (SOA) yields from NO₃ radical + isoprene based on nighttime aircraft power plant plume transects

Juliane L. Fry, Steven S. Brown, Ann M. Middlebrook, Peter M. Edwards, Pedro Campuzano-Jost, Douglas A. Day, José L. Jimenez, Hannah M. Allen, Thomas B. Ryerson, Ilana Pollack, Martin Graus, Carsten Warneke, Joost A. de Gouw, Charles A. Brock, Jessica Gilman, Brian M. Lerner, William P. Dubé, Jin Liao, and André Welti

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Final revised paper (published on 16 Aug 2018)
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Preprint (discussion started on 21 Mar 2018)
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Status: closed

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

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RC1: 'review', Anonymous Referee #1, 20 Apr 2018
RC2: 'Review of Fry et al.', Anonymous Referee #2, 23 Apr 2018
RC3: 'Review on „Secondary Organic Aerosol (SOA) yields from NO3 radical + isoprene based on nighttime aircraft power plant plume transects“ by Fry et al.', Anonymous Referee #3, 05 May 2018
AC1: 'Response to all reviewers', Juliane Fry, 09 Jun 2018

Peer-review completion

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

AR by Juliane Fry on behalf of the Authors (09 Jun 2018)

ED: Referee Nomination & Report Request started (22 Jun 2018) by Jason Surratt

RR by Anonymous Referee #2 (08 Jul 2018)

RR by Anonymous Referee #1 (08 Jul 2018)

RR by Anonymous Referee #3 (22 Jul 2018)

Suggestions for revision or reasons for rejection

Review for revised manuscript „Secondary Organic Aerosol (SOA) yields from NO3 radical + isoprene based nighttime aircraft power plant plume transects“ by J. L. Fry et al.

Fry et al. considerably improved the manuscript in their revised version. Yet there remains one major point, which needs modification before the manuscript can be published.

This reviewer requested, to show the uncertainty induced by not knowing the ratio R of NO2+/NO+ from the organic nitrates present in the aerosol. One such approach – as suggested in the review – would be a discussion on the impact of lower R on derived SOA yield. As shown in figure 3 a significant fraction of data points (eyeballing > 30%) shows R values below 0.175. As mentioned in the review, applying an R value of 0.1 (the lower envelope of the data), would reduce SOA yields to 13%, values comparable to the literature cited by the authors. The authors do not explain why they consider this comparably large number of data points as invalid, or within errors the same as R = 0.175.

The response of the authors implies that they assume an average of literature R values to be relevant to the conditions they encounter in a regime where SOA is formed from the nighttime reaction of isoprene with NO3. This is not understandable, when only one reference (Rollins et al., 2009) explored organic nitrates formed from controlled chamber studies exploring isoprene + NO3 reactions. That reference indicates an R value of 0.1. Why would other systems, with organic nitrates formed from e.g. aromatics (Sato et al.) or selected according to availability (Farmer et al.), be considered of the same relevance in this case?

The major finding in the study, namely a larger SOA yield in the plumes than in previous chamber studies, directly depends on the R value used to calculate organic nitrate mass. Therefore a discussion of the uncertainty imposed by applying an unknown R value is mandatory to inform the reader on the certainty with which organic nitrate mass concentrations can be derived from AMS data sets. One such way is the application of an R-value as low as justifiable by the data, as this implies the analysis of data with respect to lower limits of organic nitrate mass and SOA yields.

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ED: Publish subject to minor revisions (review by editor) (22 Jul 2018) by Jason Surratt

AR by Juliane Fry on behalf of the Authors (31 Jul 2018)

ED: Publish as is (01 Aug 2018) by Jason Surratt

AR by Juliane Fry on behalf of the Authors (02 Aug 2018) Manuscript

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Short summary

This paper uses measurements made during research aircraft flights through power plant smokestack emissions plumes as a natural laboratory in the field experiment. We investigated a specific source of airborne particulate matter from the combination of human-produced NO_x pollutant emissions (the smokestack plumes) with isoprene emitted by naturally by trees in the southeastern United States. These field-based yields appear to be higher than those typically measured in chamber studies.

Secondary organic aerosol (SOA) yields from NO3 radical + isoprene based on nighttime aircraft power plant plume transects

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Interactive discussion

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Secondary organic aerosol (SOA) yields from NO₃ radical + isoprene based on nighttime aircraft power plant plume transects