An instrument for in situ measurement of total ozone reactivity

Sommariva, Roberto; Kramer, Louisa J.; Crilley, Leigh R.; Alam, Mohammed S.; Bloss, William J.

doi:https://doi.org/10.5194/amt-13-1655-2020

Articles | Volume 13, issue 3

https://doi.org/10.5194/amt-13-1655-2020

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

https://doi.org/10.5194/amt-13-1655-2020

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

Articles | Volume 13, issue 3

Research article

|

02 Apr 2020

Research article |

| 02 Apr 2020

An instrument for in situ measurement of total ozone reactivity

Roberto Sommariva, Louisa J. Kramer, Leigh R. Crilley, Mohammed S. Alam, and William J. Bloss

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Final revised paper (published on 02 Apr 2020)
Preprint (discussion started on 02 Aug 2019)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Review of “An instrument for in-situ measurement of total ozone reactivity”, Sommariva et al., doi.org/10.5194/amt-2019-294', Anonymous Referee #1, 30 Aug 2019
- AC1: 'Response to Referee #1', Roberto Sommariva, 07 Jan 2020
RC2: 'Interactive comment on “An instrument for in-situ measurement of total ozone reactivity” by Roberto Sommariva et al.', Anonymous Referee #2, 03 Sep 2019
- AC2: 'Response to Referee #2', Roberto Sommariva, 07 Jan 2020

Peer-review completion

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

AR by Roberto Sommariva on behalf of the Authors (21 Jan 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (23 Jan 2020) by Hendrik Fuchs

RR by Anonymous Referee #2 (06 Feb 2020)

Suggestions for revision or reasons for rejection

1. General comments:

In this manuscript, authors focused on total ozone reactivity, built and characterized their instrument in the laboratory, and tested it in the glasshouse. This study is positioned as a basic research of the instrument and a demonstration for measuring BVOCs emission from plants. Ozone reactivity of BVOCs is interesting for investigating BVOCs. Thus, the reviewer believes that this work has an important implication and is significant enough to be published in this journal. In the revised manuscript, descriptions have been modified and readers can understand clearly what authors want to express. The reviewer recommends that this paper be published in this journal after response to a few minor comments as follows.

2. Minor specific comments:

2-1. Lines 423-425, 459-467, and Fig.8:
Authors examined the glasshouse experiments under 'quasi-ambient' conditions, in a glasshouse containing plants, subject to inflow of ambient air. Authors want to say that such 'semi-enclosed system' can realize the 'quasi-ambient' conditions, and that such quasi-ambient conditions can cause diurnal variations of BVOCs inside the house due to the variation of OH radical in the ambient conditions like Hellen et al.(2018). The reviewer feels that it is interesting in view of behavior of BVOCs. Now the reviewer wants to know authors' opinion on the situation of OH radical in such glasshouse. During daytime, if BVOCs in the house can decrease due to OH radical, in-situ OH radical formation and recycling (chain reactions) in the air of the glasshouse are essential. (Ambient OH radical cannot contribute to significant decrease of BVOCs inside the house. Chain reactions of OH radical are essential.) In the glasshouse, are contributing factors of OH formation and recycling, that is, photochemical parameters like solar radiation, water vapor, ozone concentration, and so on, sufficient? Meanwhile, as an observed fact, the diurnal variation of ozone reactivity (BVOCs) had peaks around the dawn. Then, at least, it is desirable to add a brief description on such points in the manuscript, in order to clarify the position of this study (glasshouse experiment) relative to 'true' ambient conditions.
(For example; these are only preliminary examples; please modify descriptions:) At the end of Sect. 5.3 (around Line 467), 'In this study, as a results of glasshouse experiments, it was suggested (possible) that observed diurnal variations of ozone reactivity (BVOCs) inside the glasshouse could be dominated by such daytime removal of BVOCs by OH radical (photochemical chain reactions) as in the atmosphere. Even inside the glasshouse (quasi-ambient conditions), BVOCs can be dominated by photochemical OH radical like under true ambient conditions.'

2-2. Fig.8 (estimation of the effects of temperature):
Authors estimated the reactivities considering ambient temperature (dependence of reaction rate coefficients on temperature). However, observed reactivities can be influenced directly by 'the temperature of sample gas in the reactor' (temperature during reactions in the reactor), not directly by 'the ambient temperature'. Would you please confirm them? (And, if necessary, descriptions can be modified and/or added.) If the analyzer was utilized in the glasshouse and the reactor temperature was similar to the air temperature in the glasshouse, would you please add any descriptions anywhere?
temperature inside the glasshouse
? => reactor temperature, sample gas temperature
=> rate coefficients & ozone reactivities

2-3. Table 1 (revised): Would you please consider significant digits properly?

2-4. Lines 622-624 'Sommariva et al.' can be updated to the recent version, Geosci. Model Dev., 13, 169–183, 2020.

End of comments.

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ED: Publish subject to minor revisions (review by editor) (06 Feb 2020) by Hendrik Fuchs

AR by Roberto Sommariva on behalf of the Authors (14 Feb 2020) Author's response Manuscript

ED: Publish as is (17 Feb 2020) by Hendrik Fuchs

Post-review adjustments

AA: Author's adjustment | EA: Editor approval

AA by Roberto Sommariva on behalf of the Authors (23 Mar 2020) Author's adjustment Manuscript

EA: Adjustments approved (23 Mar 2020) by Hendrik Fuchs

Short summary

Ozone is a key atmospheric pollutant formed through chemical processing of natural and anthropogenic emissions and removed by reaction with organic compounds emitted by plants. We describe a new instrument – the Total Ozone Reactivity System or TORS – that measures the total loss of ozone in the troposphere. The objective of the TORS instrument is to provide an estimate of the organic compounds emitted by plants which are not measured and thus to improve our understanding of the ozone budget.