Atmospheric Chemistry and Physics (Aug 2023)
Nighttime NO emissions strongly suppress chlorine and nitrate radical formation during the winter in Delhi
- S. L. Haslett,
- S. L. Haslett,
- D. M. Bell,
- V. Kumar,
- V. Kumar,
- J. G. Slowik,
- D. S. Wang,
- S. Mishra,
- N. Rastogi,
- A. Singh,
- A. Singh,
- D. Ganguly,
- J. Thornton,
- F. Zheng,
- Y. Li,
- W. Nie,
- Y. Liu,
- W. Ma,
- C. Yan,
- M. Kulmala,
- M. Kulmala,
- M. Kulmala,
- K. R. Daellenbach,
- D. Hadden,
- D. Hadden,
- U. Baltensperger,
- A. S. H. Prevot,
- S. N. Tripathi,
- S. N. Tripathi,
- C. Mohr,
- C. Mohr,
- C. Mohr
Affiliations
- S. L. Haslett
- Department of Environmental Science, Stockholm University, Stockholm, Sweden
- S. L. Haslett
- Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
- D. M. Bell
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- V. Kumar
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- V. Kumar
- now at: Institut National de l'Environnement Industriel et des Risques (INERIS), Parc Technologique ALATA, 60550 Vemeuil-en-Halatte, France
- J. G. Slowik
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- D. S. Wang
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- S. Mishra
- Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, India
- N. Rastogi
- Geosciences Division, Physical Research Laboratory, Ahmedabad, India
- A. Singh
- Geosciences Division, Physical Research Laboratory, Ahmedabad, India
- A. Singh
- now at: Department of Environmental Studies, University of Delhi, Delhi 110007, India
- D. Ganguly
- Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi, India
- J. Thornton
- Department of Atmospheric Sciences, University of Washington, Seattle, WA, USA
- F. Zheng
- Aerosol and Haze Laboratory, Beijing Advanced Innovation Centre for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
- Y. Li
- Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China
- W. Nie
- Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China
- Y. Liu
- Aerosol and Haze Laboratory, Beijing Advanced Innovation Centre for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
- W. Ma
- Aerosol and Haze Laboratory, Beijing Advanced Innovation Centre for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
- C. Yan
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
- M. Kulmala
- Aerosol and Haze Laboratory, Beijing Advanced Innovation Centre for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
- M. Kulmala
- Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China
- M. Kulmala
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
- K. R. Daellenbach
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
- D. Hadden
- Department of Environmental Science, Stockholm University, Stockholm, Sweden
- D. Hadden
- Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
- U. Baltensperger
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- A. S. H. Prevot
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- S. N. Tripathi
- Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, India
- S. N. Tripathi
- Department of Sustainable Energy Engineering, Indian Institute of Technology Kanpur, Kanpur, India
- C. Mohr
- Department of Environmental Science, Stockholm University, Stockholm, Sweden
- C. Mohr
- Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
- C. Mohr
- now at: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- DOI
- https://doi.org/10.5194/acp-23-9023-2023
- Journal volume & issue
-
Vol. 23
pp. 9023 – 9036
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 nighttime 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 that is 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 nighttime NO has the potential to increase both nocturnal oxidation via NO3 and the production of Cl during the day.
