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Extreme Concentrations of Nitric Oxide Control Daytime Oxidation and Quench Nocturnal Oxidation Chemistry in Delhi during Highly Polluted Episodes.
Nelson, Beth S; Bryant, Daniel J; Alam, Mohammed S; Sommariva, Roberto; Bloss, William J; Newland, Mike J; Drysdale, Will S; Vaughan, Adam R; Acton, W Joe F; Hewitt, C Nicholas; Crilley, Leigh R; Swift, Stefan J; Edwards, Pete M; Lewis, Alastair C; Langford, Ben; Nemitz, Eiko; Gadi, Ranu; Gurjar, Bhola R; Heard, Dwayne E; Whalley, Lisa K; Sahin, Ülkü A; Beddows, David C S; Hopkins, James R; Lee, James D; Rickard, Andrew R; Hamilton, Jacqueline F.
Afiliação
  • Nelson BS; Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
  • Bryant DJ; Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
  • Alam MS; School of Biosciences, University of Nottingham, Sutton Bonington, Leicestershire LE12 5RD, U.K.
  • Sommariva R; School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, U.K.
  • Bloss WJ; School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, U.K.
  • Newland MJ; Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
  • Drysdale WS; Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
  • Vaughan AR; National Centre for Atmospheric Science, University of York, Heslington, York YO10 5DD, U.K.
  • Acton WJF; Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
  • Hewitt CN; Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YW, U.K.
  • Crilley LR; Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YW, U.K.
  • Swift SJ; School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, U.K.
  • Edwards PM; Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
  • Lewis AC; Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
  • Langford B; Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
  • Nemitz E; National Centre for Atmospheric Science, University of York, Heslington, York YO10 5DD, U.K.
  • Shivani; UK Centre for Ecology and Hydrology, Penicuik, Midlothian, Edinburgh EH26 0QB, U.K.
  • Gadi R; UK Centre for Ecology and Hydrology, Penicuik, Midlothian, Edinburgh EH26 0QB, U.K.
  • Gurjar BR; Department of Applied Sciences and Humanities, Indira Gandhi Delhi Technical University for Women, Delhi 110006, India.
  • Heard DE; Department of Applied Sciences and Humanities, Indira Gandhi Delhi Technical University for Women, Delhi 110006, India.
  • Whalley LK; Indian Institute of Technology, Roorkee, Uttarakhand 247667, India.
  • Sahin ÜA; School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
  • Beddows DCS; School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
  • Hopkins JR; National Centre for Atmospheric Science, University of Leeds, Leeds LS2 9JT, U.K.
  • Lee JD; Istanbul University-Cerrahpasa, Engineering Faculty, Environmental Engineering Department, Avcilar, 34320 Istanbul, Turkey.
  • Rickard AR; School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, U.K.
  • Hamilton JF; National Centre for Atmospheric Science, University of Birmingham, Birmingham B15 2TT, U.K.
Environ Sci Technol Lett ; 10(6): 520-527, 2023 Jun 13.
Article em En | MEDLINE | ID: mdl-37333938
ABSTRACT
Delhi, India, suffers from periods of very poor air quality, but little is known about the chemical production of secondary pollutants in this highly polluted environment. During the postmonsoon period in 2018, extremely high nighttime concentrations of NOx (NO and NO2) and volatile organic compounds (VOCs) were observed, with median NOx mixing ratios of ∼200 ppbV (maximum of ∼700 ppbV). A detailed chemical box model constrained to a comprehensive suite of speciated VOC and NOx measurements revealed very low nighttime concentrations of oxidants, NO3, O3, and OH, driven by high nighttime NO concentrations. This results in an atypical NO3 diel profile, not previously reported in other highly polluted urban environments, significantly perturbing nighttime radical oxidation chemistry. Low concentrations of oxidants and high nocturnal primary emissions coupled with a shallow boundary layer led to enhanced early morning photo-oxidation chemistry. This results in a temporal shift in peak O3 concentrations when compared to the premonsoon period (1200 and 1500 local time, respectively). This shift will likely have important implications on local air quality, and effective urban air quality management should consider the impacts of nighttime emission sources during the postmonsoon period.

Texto completo: 1 Base de dados: MEDLINE Idioma: En Ano de publicação: 2023 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Idioma: En Ano de publicação: 2023 Tipo de documento: Article