[Analysis of O3 Pollution Characteristics, Formation Sensitivity, and Transport Impact in Southern Nanjing]

Xin-Mei Zheng; Kun Hu; Ming Wang; Fang-Jian Xie; Yan Wang

doi:10.13227/j.hjkx.202207171

[Analysis of O₃ Pollution Characteristics, Formation Sensitivity, and Transport Impact in Southern Nanjing]

Huan Jing Ke Xue. 2023 Aug 8;44(8):4231-4240. doi: 10.13227/j.hjkx.202207171.

[Article in Chinese]

Authors

Xin-Mei Zheng¹, Kun Hu², Ming Wang³, Fang-Jian Xie¹, Yan Wang¹

Affiliations

¹ Nanjing Municipal Academy of Ecological and Environment Protection Science, Nanjing 210018, China.
² State Joint Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
³ Collaborative Innovation Center of Ambient Environment and Equipment Technology, Jiangsu Key Laboratory of Ambient Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China.

PMID: 37694618
DOI: 10.13227/j.hjkx.202207171

Abstract

As one of the most important city clusters in China, surface ozone (O₃) pollution in the Yangtze River Delta (YRD) Region has become a prominent air quality problem in recent years. Online observations of ambient O₃, nitrogen oxides (NO_x), and volatile organic compounds (VOCs) were conducted in southern Nanjing from July-September 2020 and April-May 2021. On this basis, the pollution characteristics of O₃ were analyzed. The O₃-VOCs-NO_x sensitivity and the transport influence of its precursors were further discussed using models. The frequency statistics of the daily maximum 8-hour moving average (DMA-8h O₃) and hourly concentration (O₃-1h) showed that O₃ pollution in southern Nanjing was more serious than that in urban areas. Three typical O₃ pollution episodes were selected during the whole observation period, which included August 16^th-27^th, 2020; September 3^rd-11^th, 2020; and May 17^th-25^th, 2021. The O₃-VOCs-NO_x sensitivities in these three pollution episodes were analyzed using the observation-based model (OBM). The results of the relative incremental reactivity (RIR) and empirical kinetics modeling approach (EKMA) showed that the sensitivities of O₃ formation in the three pollution episodes were in the NO_x-limited regime, the transition regime, and the VOCs-limited regime, respectively. This difference in O₃-VOCs-NO_x sensitivity reflects that the site may have been influenced by transport. Therefore, the potential source contribution function (PSCF) and the concentration weighted trajectory (CWT) method were further used to analyze the potential source areas of NO_x, VOCs, and O₃ in these three pollution episodes. The results showed that there were obvious regional transport effects of NO_x, VOCs, and O₃ in these three pollution episodes. The location of potential sources differed in these three pollution episodes, which were affected by the eastern cities of the Lishui site; the urban area of Nanjing and eastern area of Anhui Province; and the urban area of Nanjing and the middle of the YRD Region, respectively. The impact of transport on O₃ and its precursors also indicated the necessity of regional joint prevention and control of O₃ pollution in the YRD Region.

Keywords: Nanjing; O3-VOCs-NOx sensitivity; observation-based model (OBM); potential source analysis; transport impact.

Publication types

English Abstract