The importance of NOx control for peak ozone mitigation based on a sensitivity study using CMAQ‐HDDM‐3D model during a typical episode over the Yangtze River delta region, China. [Dataset]

Abstract

Ground-level ozone (O3) is formed primarily from photochemical reactions between volatile organic compounds (VOCs) and nitrogen oxides (NOx). Besides, O3 and other pollutants also frequently undergo various other processes such as vertical/horizontal transport and deposition. These chemical and physical processes cause the complexity of O3 formation and pose challenges to its mitigation. For instance, in the Yangtze River Delta (YRD) region of eastern China, ground-level O3 has been among the main pollutants hindering air quality compliance. In this study, advanced modeling techniques based on the state-of-science community multiscale air quality model were utilized to understand at a regional scale the nonlinear response of O3 to NOx and VOCs, as well as to explore the contributions of these processes to O3 during the pollution episode between 24th and 31th July 2018 over this region. The results emphasized that O3 sensitivity to NOx was high and positive in the afternoon over most areas including the urban cores. This strongly indicates that NOx emission reductions could be an important way to reduce peak O3 and the more the reduction of NOx, the faster the decrease of peak O3. These findings provide important insights into the formulation of policies and regulations to mitigate O3 pollution.

Citation

WANG, Y., YALUK, E.A., CHEN, H., JIANG, S., HUANG, L., ZHU, A., XIAO, S., XUE, J., LU, G., BIAN, J., KASEMSAN, M., ZHANG, K., LIU, H., TONG, H., OOI, C.G., CHAN, A. and LI, L. 2022. The importance of NOx control for peak ozone mitigation based on a sensitivity study using CMAQ-HDDM-3D model during a typical episode over the Yangtze River delta region, China. [Dataset]. Journal of geophysical research: atmospheres [online], 127(9), article e2022JD036555. Available from: https://doi.org/10.1029/2022jd036555

• Acceptance Date: Sep 11, 2022
• Online Publication Date: Sep 30, 2022
• Publication Date: Oct 16, 2022
• Deposit Date: Apr 4, 2023
• Publicly Available Date: Apr 4, 2023
• Publisher: Wiley
• DOI: https://doi.org/10.1029/2022jd036555
• Keywords: Ground-level ozone (O3); Yangtze River Delta (YRD); Photochemical reactions; Volatile organic compounds (VOCs); Nitrogen oxides (NOx)
• Public URL: https://rgu-repository.worktribe.com/output/1930696
• Related Public URLs: https://rgu-repository.worktribe.com/output/1888356 (Journal article)
• Type of Data: XLSX, DOCX and accompanying TXT file.
• Collection Date: Jul 31, 2018
• Collection Method: In this work, CMAQv5.3.2 was used to simulate the air quality during the typical O3 pollution episode from 24 to 31 July 2018, and HDDM-3D and process analysis (PA) tools embedded in the CMAQ model were used to examine the O3-VOCs-NOx sensitivities and the main contributors to O3, respectively. Integrated process rate (IPR) and integrated reaction rate (IRR) were computed at each model grid-cell by the PA tool to account for the hourly changes of O3 concentrations. The IPR calculated the contributions from interactions of various atmospheric processes such as gas-phase chemistry (CHEM); dry deposition (DDEP); cloud processes with aqueous chemistry (CLDS); vertical advection (ZADV); horizontal advection (HADV); vertical diffusion (VDIF); and horizontal diffusion (HDIF). With this, we defined VERT to represent vertical transport processes (i.e., the sum of ZADV and HDIF), and HORT to represent the horizontal transport processes (i.e., the sum of HDIF and HADV). Meanwhile, IRR quantified the variation of chemical production (or loss) caused by each chemical reaction rate in the mechanism.