Preprints
https://doi.org/10.5194/acp-2022-548
https://doi.org/10.5194/acp-2022-548
 
12 Aug 2022
12 Aug 2022
Status: this preprint is currently under review for the journal ACP.

Elucidate the Formation Mechanism of Particulate Nitrate Based on Direct Radical Observations in Yangtze River Delta summer 2019

Tianyu Zhai1, Keding Lu1,2, Haichao Wang3, Shengrong Lou4, Xiaorui Chen1,a, Renzhi Hu5, and Yuanhang Zhang1,2 Tianyu Zhai et al.
  • 1State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
  • 2Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science & Technology, Nanjing 210044, China
  • 3School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou 510275, China
  • 4State Environmental Protection Key Laboratory of Formation and Prevention of the Urban Air Complex, Shanghai Academy of Environmental Sciences, Shanghai, 200223, China
  • 5Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei, 230031, China
  • anow at: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China

Abstract. Particulate nitrate (NO3-) is the one of the dominant components of fine particles in China, especially during pollution episodes, and has a significant impact on human health, air quality and climate. Here a comprehensive field campaign which focus on the atmospheric oxidation capacity and aerosol formation, and their effects in Yangtze River Delta (YRD) had been conducted from May to June, 2019 at a regional site in Changzhou, Jiangsu province in China. The concentration of NO3-, OH radical, N2O5, NO2, O3 and relevant parameters were measured simultaneously. We showed a high NO3- mass concentration with 10.6 ± 8.9 μg m-3 on average, which accounted for 38.3 % of water-soluble components and 32.0 % total PM2.5, and followed by the proportion of sulfate, ammonium and chloride by 26.0 %, 18.0 % and 2.0 %, respectively. This result confirmed the heavy nitrate pollution in eastern China not only happened in winter but also summer time. High nitrate oxidation ratio (NOR) during this study emphasizes the fast nitrate formation capacity in YRD. It is found that OH + NO2 at daytime dominates nitrate formation on clean days while N2O5 hydrolysis largely enhanced and become comparable with that of OH + O2 during polluted days (47.1 % and 52.9 %). An updated observed-constrain Empirical Kinetic Modeling Approach (EKMA) was used to assess the kinetic controlling factors of both local O3 and NO3- productions, which indicated that O3-targeting scheme (VOCs: NOx = 2:1) is effective to mitigate the O3 and nitrate pollution coordinately during summertime in this region. Our results promote the understanding of nitrate pollution mechanisms and mitigation based on field observation and model simulation, and call for more attentions to nitrate pollutions in summertime.

Tianyu Zhai et al.

Status: open (until 23 Oct 2022)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on acp-2022-548', Anonymous Referee #1, 01 Sep 2022 reply

Tianyu Zhai et al.

Tianyu Zhai et al.

Viewed

Total article views: 242 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
173 64 5 242 1 5
  • HTML: 173
  • PDF: 64
  • XML: 5
  • Total: 242
  • BibTeX: 1
  • EndNote: 5
Views and downloads (calculated since 12 Aug 2022)
Cumulative views and downloads (calculated since 12 Aug 2022)

Viewed (geographical distribution)

Total article views: 298 (including HTML, PDF, and XML) Thereof 298 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 28 Sep 2022
Download
Short summary
Particulate nitrate is a growing issue in the air pollution. Based on a comprehensive field measurement, we show a heavy nitrate pollution in eastern China in summer. OH reacts with NO2 at daytime dominates nitrate formation on clean days while N2O5 hydrolysis largely enhanced and become comparable with that of OH reacts with O2 during polluted days (47.1 % and 52.9 %). Model simulation indicates that VOCs: NOx = 2:1 is effective to mitigate the O3 and nitrate pollution coordinately.
Altmetrics