Nighttime NO emissions strongly suppress chlorine and nitrate radical formation during the winter in Delhi
Year: 2023
Type: article
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.
Authors: 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, Claudia Mohr
Institutions: Stockholm University, Bolin Centre for Climate Research, Paul Scherrer Institute, Institut national de l'environnement industriel et des risques, Indian Institute of Technology Kanpur, Physical Research Laboratory, University of Delhi, Indian Institute of Technology Delhi, University of Washington, Beijing University of Chemical Technology, Nanjing University, University of Helsinki
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,444
Awards: Source Apportionment of Organics in ambient air including Primary, Secondary Organic Aerosols and trace Gases (SAOPSOAG), G5531157831, Formation of secondary organic aerosol from anthropogenic and biogenic sources in heavily polluted urban environments, Particulate air pollution sources in low-income megacities
OpenAlex ID: W4385907299