Driving Factors of PM2.5 Pollution Rebound in North China Plain in Early 2023

An unexpected rebound in PM2.5 pollution was observed in the North China Plain (NCP) during the post-COVID-19 period in 2023 compared to 2022. Identifying the driving factors behind this phenomenon is critical for developing PM2.5 mitigation strategies. In this study, the Community Multiscale Air Quality (CMAQ) model, coupled with near-real-time emission inventories, was utilized to quantify the contributions of meteorological conditions and anthropogenic emissions to the severe PM2.5 rebound observed in February 2023. The results revealed that anthropogenic emissions and meteorological factors accounted for 59% and 41% of the rebound, respectively. Increased activities in transportation, domestic combustion, and power and industrial sectors significantly elevated NOX, SO2, and primary particulate emissions. Key meteorological drivers included higher relative humidity, reduced wind speed, and a lower atmospheric boundary layer height, which were linked to anomalous southerly wind patterns over the NCP. This study underscores the pivotal role of transitioning energy and industrial structures in fostering a green economic recovery, which is crucial for achieving sustained and substantial improvements in air quality over the NCP.

2023年新冠疫情后时期，华北平原（North China Plain, NCP）观测到细颗粒物（PM2.5）污染相较于2022年出现意外反弹。厘清该现象背后的驱动因素，对于制定PM2.5污染防控策略至关重要。本研究采用耦合近实时排放清单的多尺度空气质量（Community Multiscale Air Quality, CMAQ）模型，对2023年2月观测到的重度PM2.5反弹事件中气象条件与人为排放的贡献进行量化分析。研究结果显示，人为排放与气象因素分别对此次反弹贡献了59%与41%的份额。交通、生活燃烧、电力与工业领域的活动增强，显著推高了氮氧化物（NOX）、二氧化硫（SO2）以及一次颗粒物的排放量。关键气象驱动因子包括相对湿度升高、风速降低以及大气边界层高度下降，上述气象条件与华北平原上空出现的异常南风环流密切相关。本研究强调，推动能源与产业结构转型以促进绿色经济复苏，对于实现华北平原空气质量的持续显著改善具有关键作用。