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https://doi.org/10.5194/egusphere-2023-497
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/egusphere-2023-497
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
28 Mar 2023
| 28 Mar 2023
Night-time NO emissions strongly suppress chlorine and nitrate radical formation during the winter in Delhi
Abstract. Atmospheric pollution in urban regions is highly influenced by oxidants due to their important role in the formation of secondary organic aerosol (SOA) and smog. These include the nitrate radical (NO3), which is typically considered a night-time oxidant, and the chlorine radical (Cl), an extremely potent oxidant that can be released in the morning in chloride-rich environments as a result of nocturnal build-up of nitryl chloride (ClNO2). Chloride makes up a higher percentage of particulate matter in Delhi than has been observed anywhere else in the world, which results in Cl having an unusually strong influence in this city. Here, we present observations and model results revealing that atmospheric chemistry in Delhi exhibits an unusual diel cycle, controlled by high concentrations of NO during the night. As a result of this, the formation of both NO3 and dinitrogen pentoxide (N2O5), a precursor of ClNO2 and thus Cl, are suppressed at night and increase to unusually high levels during the day. Our results indicate that a substantial reduction in night-time NO has the potential to increase both nocturnal oxidation via NO3 and the production of Cl during the day.
How to cite. Haslett, S. L., Bell, D. M., Kumar, V., Slowik, J. G., Wang, D. S., Mishra, S., Rastogi, N., Singh, A., Ganguly, D., Thornton, J., Zheng, F., Li, Y., Nie, W., Liu, Y., Ma, W., Yan, C., Kulmala, M., Daellenbach, K. R., Hadden, D., Baltensperger, U., Prevot, A. S. H., Tripathi, S. N., and Mohr, C.: Night-time NO emissions strongly suppress chlorine and nitrate radical formation during the winter in Delhi, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2023-497, 2023.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Atmospheric Chemistry and Physics. The peer-review process was guided by an independent editor, and the authors also have no other competing interests to declare.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.Download & links
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Journal article(s) based on this preprint
17 Aug 2023
Nighttime NO emissions strongly suppress chlorine and nitrate radical formation during the winter in Delhi
Sophie L. Haslett, David M. Bell, Varun Kumar, Jay G. Slowik, Dongyu S. Wang, Suneeti Mishra, Neeraj Rastogi, Atinderpal Singh, Dilip Ganguly, Joel Thornton, Feixue Zheng, Yuanyuan Li, Wei Nie, Yongchun Liu, Wei Ma, Chao Yan, Markku Kulmala, Kaspar R. Daellenbach, David Hadden, Urs Baltensperger, Andre S. H. Prevot, Sachchida N. Tripathi, and Claudia Mohr
Atmos. Chem. Phys., 23, 9023–9036, https://doi.org/10.5194/acp-23-9023-2023, https://doi.org/10.5194/acp-23-9023-2023, 2023
Short summary
Short summary
In Delhi, some aspects of daytime and nighttime atmospheric chemistry are inverted, and parodoxically, vehicle emissions may be limiting other forms of particle production. This is because the nighttime emissions of nitrogen oxide (NO) by traffic and biomass burning prevent some chemical processes that would otherwise create even more particles and worsen the urban haze.
Interactive discussion
Status: closed
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor
| : Report abuse
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RC1: 'Comment on egusphere-2023-497', Anonymous Referee #1, 03 May 2023
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AC1: 'Reply on RC1', Sophie Haslett, 22 Jun 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-497/egusphere-2023-497-AC1-supplement.pdf
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AC1: 'Reply on RC1', Sophie Haslett, 22 Jun 2023
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RC2: 'Comment on egusphere-2023-497', Anonymous Referee #2, 17 May 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-497/egusphere-2023-497-RC2-supplement.pdf
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AC2: 'Reply on RC2', Sophie Haslett, 22 Jun 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-497/egusphere-2023-497-AC2-supplement.pdf
-
AC2: 'Reply on RC2', Sophie Haslett, 22 Jun 2023
Interactive discussion
Status: closed
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor
| : Report abuse
-
RC1: 'Comment on egusphere-2023-497', Anonymous Referee #1, 03 May 2023
This manuscript presents an atmospheric chemistry story from 25 days of data (11 January – 5 February) from a FIGAERO-CIMS complemented with AMS, NOx, and O3 measurements in Delhi, India. The authors use these measurements with a 0-D chemical box model to understand N2O5 sources and sinks. The study finds that the high night-time NO depletes O3, NO3, and N2O5 (a precursor to ClNO2 and thus Cl). The authors finally suggest that decreasing NO emissions will result in NO3 becoming an important nocturnal oxidant during the night and Cl during the day. The manuscript provides interesting insights into the “unusual” atmospheric chemistry, especially the role of various atmospheric oxidants, in Delhi which may be relevant for other polluted cities in the Indo-Gangetic Plain where there is similar combination of large emissions (including NOx) and unfavorable (nighttime) meteorology.
Some comments:
- The authors should be careful in the distinction between “emissions” and “levels”. These are not always interchangeable. As the authors themselves discuss in the excellent discussion in the last paragraph of page-9, boundary layer dynamics (unfavorable nighttime meteorology) plays an important role in Delhi. As such, it may not be simply the “nighttime NO emissions”, but the “nighttime NO levels” that are of relevant to the discussion. While this may seem trivial, this is extremely relevant from a policy perspective and specifically how the authors discuss policy implications. I suggest that the authors carefully go through the manuscript and check if the use of “emissions” and “levels” is correct and intentional.
- Delhi has large seasonal variations in pollution loadings (including aerosol and gas) because of a combination of changing sources (especially heating in winter) and meteorology. As a result, a 25-day study from January (2019) should be careful in generalizing the loadings (including chloride) and chemistry for the entire year. I am not saying that the findings are not important, but that they should be put in context of the study period. For example, the authors could use previously published year-round data for aerosol composition and NOx (even if no FIGAERO-CIMS) to put the study period in context.
- The authors should also include the study-period in the figure captions. For example, instead of “The diel cycles of key oxidants and oxidation products in Delhi” it should be “The diel cycles of key oxidants and oxidation products in Delhi during the study period” (even better if you include the study dates)
- How are “night” and “day” defined for the analysis? I could not find this in the methods.
- In Section 2.1, the name of the centre is incorrectly written. I believe the correct name of the centre is the same as the affiliation of one of the authors of the study. Also, are the authors sure that the distance from the major roadway is just 80m? Please also include which floor the measurements were conducted in.
- In Section 2.3, line 151, the measurement location for meteorological data should be included.
- In Figure 2, adding MLH from reanalysis dataset such as ERA5 or MERRA2 may provide interesting insights.
Thanks to the authors for writing an interesting atmospheric chemistry manuscript. I hope that the comments above help improve the article.
Citation: https://doi.org/10.5194/egusphere-2023-497-RC1 -
AC1: 'Reply on RC1', Sophie Haslett, 22 Jun 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-497/egusphere-2023-497-AC1-supplement.pdf
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RC2: 'Comment on egusphere-2023-497', Anonymous Referee #2, 17 May 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-497/egusphere-2023-497-RC2-supplement.pdf
-
AC2: 'Reply on RC2', Sophie Haslett, 22 Jun 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-497/egusphere-2023-497-AC2-supplement.pdf
-
AC2: 'Reply on RC2', Sophie Haslett, 22 Jun 2023
Peer review completion
AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload
AR by Sophie Haslett on behalf of the Authors (22 Jun 2023)
Author's response
Author's tracked changes
Manuscript
ED: Publish as is (27 Jun 2023) by Lea Hildebrandt Ruiz
AR by Sophie Haslett on behalf of the Authors (09 Jul 2023)
Author's response
Manuscript
Journal article(s) based on this preprint
17 Aug 2023
Nighttime NO emissions strongly suppress chlorine and nitrate radical formation during the winter in Delhi
Sophie L. Haslett, David M. Bell, Varun Kumar, Jay G. Slowik, Dongyu S. Wang, Suneeti Mishra, Neeraj Rastogi, Atinderpal Singh, Dilip Ganguly, Joel Thornton, Feixue Zheng, Yuanyuan Li, Wei Nie, Yongchun Liu, Wei Ma, Chao Yan, Markku Kulmala, Kaspar R. Daellenbach, David Hadden, Urs Baltensperger, Andre S. H. Prevot, Sachchida N. Tripathi, and Claudia Mohr
Atmos. Chem. Phys., 23, 9023–9036, https://doi.org/10.5194/acp-23-9023-2023, https://doi.org/10.5194/acp-23-9023-2023, 2023
Short summary
Short summary
In Delhi, some aspects of daytime and nighttime atmospheric chemistry are inverted, and parodoxically, vehicle emissions may be limiting other forms of particle production. This is because the nighttime emissions of nitrogen oxide (NO) by traffic and biomass burning prevent some chemical processes that would otherwise create even more particles and worsen the urban haze.
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Sophie L. Haslett
CORRESPONDING AUTHOR
Department of Environmental Science, Stockholm University; Stockholm, Sweden
Bolin Centre for Climate Research; Stockholm, Sweden
David M. Bell
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute; 5232 Villigen PSI, Switzerland
Varun Kumar
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute; 5232 Villigen PSI, Switzerland
now at: Institut National de l’Environnement Industriel et des Risques (INERIS), Parc Technologique ALATA, 60550 Vemeuil-en-Halatte, France
Jay G. Slowik
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute; 5232 Villigen PSI, Switzerland
Dongyu S. Wang
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute; 5232 Villigen PSI, Switzerland
Suneeti Mishra
Department of Civil Engineering, Indian Institute of Technology Kanpur; Kanpur, India
Neeraj Rastogi
Geosciences Division, Physical Research Laboratory; Ahmedabad, India
Atinderpal Singh
Geosciences Division, Physical Research Laboratory; Ahmedabad, India
now at: Department of Environmental Studies, University of Delhi; Delhi 110007, India
Dilip Ganguly
Centre for Atmospheric Sciences, Indian Institute of Technology Delhi; New Delhi, India
Joel Thornton
Department of Atmospheric Sciences, University of Washington; Seattle, USA
Feixue Zheng
Aerosol and Haze Laboratory, Beijing Advanced Innovation Centre for Soft Matter Science and Engineering, Beijing University of Chemical Technology; Beijing, 100029, China
Yuanyuan Li
Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University; 210023 Nanjing, China
Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University; 210023 Nanjing, China
Yongchun Liu
Aerosol and Haze Laboratory, Beijing Advanced Innovation Centre for Soft Matter Science and Engineering, Beijing University of Chemical Technology; Beijing, 100029, China
Wei Ma
Aerosol and Haze Laboratory, Beijing Advanced Innovation Centre for Soft Matter Science and Engineering, Beijing University of Chemical Technology; Beijing, 100029, China
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki; Helsinki, Finland
Markku Kulmala
Aerosol and Haze Laboratory, Beijing Advanced Innovation Centre for Soft Matter Science and Engineering, Beijing University of Chemical Technology; Beijing, 100029, China
Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University; 210023 Nanjing, China
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki; Helsinki, Finland
Kaspar R. Daellenbach
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki; Helsinki, Finland
David Hadden
Department of Environmental Science, Stockholm University; Stockholm, Sweden
Bolin Centre for Climate Research; Stockholm, Sweden
Urs Baltensperger
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute; 5232 Villigen PSI, Switzerland
Andre S. H. Prevot
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute; 5232 Villigen PSI, Switzerland
Sachchida N. Tripathi
CORRESPONDING AUTHOR
Department of Civil Engineering, Indian Institute of Technology Kanpur; Kanpur, India
Department of Environmental Science, Stockholm University; Stockholm, Sweden
Bolin Centre for Climate Research; Stockholm, Sweden
now at: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute; 5232 Villigen PSI, Switzerland
Download
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(1394 KB) - Metadata XML
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Supplement
(706 KB) - BibTeX
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- Final revised paper
Short summary
In Delhi, some aspects of daytime and night-time atmospheric chemistry are “flipped,” and parodoxically, vehicle emissions may be limiting other forms of particle production. This is because the night-time emissions of nitrogen oxide (NO) by traffic, as well as biomass burning, prevents some chemical processes that would otherwise create even more particles, and worsen the urban haze.
In Delhi, some aspects of daytime and night-time atmospheric chemistry are “flipped,” and...
This manuscript presents an atmospheric chemistry story from 25 days of data (11 January – 5 February) from a FIGAERO-CIMS complemented with AMS, NOx, and O3 measurements in Delhi, India. The authors use these measurements with a 0-D chemical box model to understand N2O5 sources and sinks. The study finds that the high night-time NO depletes O3, NO3, and N2O5 (a precursor to ClNO2 and thus Cl). The authors finally suggest that decreasing NO emissions will result in NO3 becoming an important nocturnal oxidant during the night and Cl during the day. The manuscript provides interesting insights into the “unusual” atmospheric chemistry, especially the role of various atmospheric oxidants, in Delhi which may be relevant for other polluted cities in the Indo-Gangetic Plain where there is similar combination of large emissions (including NOx) and unfavorable (nighttime) meteorology.
Some comments:
Thanks to the authors for writing an interesting atmospheric chemistry manuscript. I hope that the comments above help improve the article.