EGUsphere

Copernicus Publications

Göttingen, Germany

10.5194/egusphere-2026-3891

Meteorological conditions drive divergent responses of co-occurring PM2.5 and O3 pollution to emission reductions and role of aerosol feedback in Beijing–Tianjin–Hebei-Shandong

Gao

¹ Zhao

¹ ³ Zhang

Meigen

https://orcid.org/0000-0002-3318-6134

² ³ Yang

Zining

https://orcid.org/0009-0009-2812-3874

⁴

State Key Laboratory of Atmospheric Environment and Extreme Meteorology (AEEM), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China

Laboratory of Atmospheric Boundary Layer, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China

University of Chinese Academy of Sciences, Beijing 100049, China

Deep Space Exploration Laboratory/School of Earth and Space Sciences/CMA-USTC Laboratory of Fengyun Remote Sensing/State Key Laboratory of Fire Science/Institute of Advanced Interdisciplinary Research on High-Performance Computing Systems and Software, University of Science and Technology of China, Hefei, China

14 07 2026

2026 1 35

2026

This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/

This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-3891/

The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-3891/egusphere-2026-3891.pdf

Co‑occurring PM2.5 and O3 pollution (Double High Pollution, DHP) presents a growing air quality concern, yet its response to emission controls under different meteorological conditions is poorly quantified. Previous studies have focused on synoptic‑scale or single meteorological variable with limited consideration of aerosol-meteorology feedback. This study investigated the DHP response to NOx–VOC emission reductions and the role of aerosol-meteorology feedback in Beijing–Tianjin–Hebei-Shandong in July 2020 using the WRF-Chem model. DHP occurred under warm (23–31 °C), moderately humid (45–80 %), and shallow boundary layer (0.5–1.1 km) conditions. These typical meteorological conditions were classified into five types: Convective, Stable, WarmHumid, DryHot, and Moderate based on boundary layer height, temperature and humidity. PM2.5 was highest under Stable and WarmHumid (~46 μg m-3) and lowest under DryHot (~40 μg m-3); O3 was highest under DryHot and Moderate (~83–84 ppb) and lowest under WarmHumid (~76 ppb). O3 responded most strongly to emission controls under WarmHumid (-25.2 % at 50 %/50 % NOx/VOC) and weakest under DryHot (-23.3 %) with stronger NOx sensitivity under WarmHumid and Convective; PM2.5 reductions were largest under Stable and WarmHumid (-20.9 % and -20.6 %) and smallest under DryHot (-15.2 %). Aerosol feedback enhanced PM2.5 reduction most under Stable and WarmHumid but weakened O3 reduction under Stable when NOx cuts were large without VOC co-reduction, driven by the most lasting PBLH increase and strong OH amplification. These results demonstrate that meteorological condition-specific strategies, particularly coordinated NOx–VOC control under stagnant and humid conditions, are essential for effective DHP mitigation.