Diurnal evolution of total column and surface atmospheric  ammonia in the megacity of Paris, France, during  an intense springtime pollution episode

Kutzner, Rebecca D.; Cuesta, Juan; Chelin, Pascale; Petit, Jean-Eudes; Ray, Mokhtar; Landsheere, Xavier; Tournadre, Benoît; Dupont, Jean-Charles; Rosso, Amandine; Hase, Frank; Orphal, Johannes; Beekmann, Matthias

doi:https://doi.org/10.5194/acp-21-12091-2021

Articles | Volume 21, issue 15

https://doi.org/10.5194/acp-21-12091-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-21-12091-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 21, issue 15

Research article

|

12 Aug 2021

Research article |

| 12 Aug 2021

Diurnal evolution of total column and surface atmospheric ammonia in the megacity of Paris, France, during an intense springtime pollution episode

Rebecca D. Kutzner, Juan Cuesta, Pascale Chelin, Jean-Eudes Petit, Mokhtar Ray, Xavier Landsheere, Benoît Tournadre, Jean-Charles Dupont, Amandine Rosso, Frank Hase, Johannes Orphal, and Matthias Beekmann

Download

Final revised paper (published on 12 Aug 2021)
Supplement to the final revised paper
Preprint (discussion started on 08 Dec 2020)
Supplement to the preprint

Interactive discussion

Status: closed

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

- Printer-friendly version

- Supplement

RC1: 'comments on the manuscript by Kutzner et al', Anonymous Referee #2, 18 Feb 2021
- AC1: 'Reply on RC1', Rebecca D. Kutzner, 25 May 2021
SC1: 'Comment on acp-2020-782', Benjamin Loubet, 09 Apr 2021
- AC2: 'Reply on SC1', Rebecca D. Kutzner, 25 May 2021

Peer-review completion

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

AR by Rebecca D. Kutzner on behalf of the Authors (25 May 2021) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (26 May 2021) by Rolf Müller

RR by Anonymous Referee #2 (13 Jun 2021)

Suggestions for revision or reasons for rejection

The authors have addressed all comments by both reviewers and the presentation of the results and the discussion have been improved. To my opinion, a few additional improvements are needed before publication of the paper in ACP.

1- Abstract: line 44-46 :“These differences are mainly explained by vertical mixing within the boundary layer, as suggested by ground-based measurements of vertical profiles of aerosol backscatter, used as tracer of the vertical distribution of pollutants in the atmospheric boundary layer”

New Comment: From your new analysis (new figure 10), i.e. calculation of the boundary layer column of NH3 as suggested by reviewer Benjamin Loubet, I understand that the difference in the diurnal patterns between surface concentrations and total column measurements can be mostly attributed to the changes in the mixing layer height, provided that boundary layer is considered well mixed and therefore homogeneous in ammonia concentrations (new Figure 10). This finding has to reflect in the abstract.

2- Earlier reviewer comment: Line 237: The reference you provide is an entire textbook. Please be specific. Which thermodynamic model is used in that simulation. (Unfortunately, the web site provided for the model in line 234 requires password, so it seems to be useless for the reader. I suggest removing it.)
Author reply: Clarified and added new information. We specify the thermodynamic model input information in Lines 254-255. “Chemical reactions are simulated using the MELCHIOR2 mechanisms scheme and tabulations from ISORROPIA model for thermodynamic equilibrium calculations of the species.” And changed the web site provided to one accessible without password: http://www.esmeralda-web.fr/accueil/index.php

New comment: I am afraid it remains unclear to me: Do I understand correct that ISORROPIA model has been used to produce tables that have been then inserted in the CHIMERE model? Or is only that the equilibrium coefficients and other thermodynamic input data from ISORROPIA have been used in some module of Chimere to calculate the equilibrium? Please further clarify.

3- New Comment: Line 313: PM2.5 levels ARE clearly enhancED (up to 80 ug m-3), as also seen in the daily averageD results of the simulations.

4- New Comment: Line 323: Reading the manuscript I understand that PM1 was measured at SIRTA while PM2.5 at other location in the Ile-de-France region. Thus, PM1 and PM2.5 measurements are not co-located. These two types of measurements could be compared when the measurements are co-located, which -to my understanding - is not the case, or when the PM2.5 measurements could be considered as characteristic of the region. It is true that the 3 PM2.5 sites provide very similar results, with the exception of the night of the 26-27 March but SITRA is not included in the triangle defined by the PM2.5 sites. I do not see how the authors exclude the fact that there might be differences in the background levels at SITRA and the other stations as well as different sources and sinks. Do the authors have another argument/evidence that the 3 PM2.5 stations are representative of the entire area including SITRA? As mentioned only with co-located observations one can relate PM1 and PM2.5 observation.

5- Line 473: act AS local sinks

6- Author reply: This is clarified in lines 625-626 of the RM. “This issue would be best addressed with chemistry-transport model simulations. “

New Comment: This sentence is misleading because ISORROPIA II is a thermodynamic equilibrium model and CHIMERE is a chemistry transport model. What is needed is coupling the CTM with ISORROPIA, and the reader is wondering why these two have not been coupled for this study to fully address the gas-to-particle conversion issue of ammonia. In addition, CHIMERE model output could have been easily used off line in the ISORROPIA II model. A better argument is needed here.

7- Author reply lines 611-614: Other processes such as surface and canopy uptake from surrounding ecosystems, depending on pH and total nitrogen input, may also explain surface concentration reductions (Massad et al., 2010, Flechard et al., 2013, Personne et al., 2015).

New Comment: Please also add light and temperature.

Hide

ED: Publish subject to minor revisions (review by editor) (28 Jun 2021) by Rolf Müller

AR by Rebecca D. Kutzner on behalf of the Authors (08 Jul 2021) Author's response Author's tracked changes Manuscript

ED: Publish subject to technical corrections (09 Jul 2021) by Rolf Müller

AR by Rebecca D. Kutzner on behalf of the Authors (12 Jul 2021) Manuscript

Download

Article (4877 KB)
Full-text XML

Short summary

Our work investigates the diurnal evolution of atmospheric ammonia concentrations during a major pollution event. It analyses it in regard of both chemical (gas–particle conversion) and physical (vertical mixing, meteorology) processes in the atmosphere. These mechanisms are key for understanding the evolution of the physicochemical state of the atmosphere; therefore, it clearly fits into the scope of Atmospheric Chemistry and Physics.