College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China.
School of Advanced Interdisciplinary Studies, Hunan University of Technology and Business, Changsha, 410205, PR China.
Environ Pollut. 2023 Aug 15;331(Pt 2):121886. doi: 10.1016/j.envpol.2023.121886. Epub 2023 May 24.
In December 2019, the New Crown Pneumonia (the COVID-19) outbroke around the globe, and China imposed a nationwide lockdown starting as early as January 23, 2020. This decision has significantly impacted China's air quality, especially the sharp decrease in PM (aerodynamic equivalent diameter of particulate matter less than or equal to 2.5 μm) pollution. Hunan Province is located in the central and eastern part of China, with a "horseshoe basin" topography. The reduction rate of PM concentrations in Hunan province during the COVID-19 (24.8%) was significantly higher than the national average (20.3%). Through the analysis of the changing character and pollution sources of haze pollution events in Hunan Province, more scientific countermeasures can be provided for the government. We use the Weather Research and Forecasting with Chemistry (WRF-Chem, V4.0) model to predict and simulate the PM concentrations under seven scenarios before the lockdown (2020.1.1-2020.1.22) and during the lockdown (2020.1.23-2020.2.14). Then, the PM concentrations under different conditions is compared to differentiate the contribution of meteorological conditions and local human activities to PM pollution. The results indicate the most important cause of PM pollution reduction is anthropogenic emissions from the residential sector, followed by the industrial sector, while the influence of meteorological factors contribute only 0.5% to PM. The explanation is that emission reductions from the residential sector contribute the most to the reduction of seven primary contaminants. Finally, we trace the source and transport path of the air mass in Hunan Province through the Concentration Weight Trajectory Analysis (CWT). We found that the external input of PM in Hunan Province is mainly from the air mass transported from the northeast, accounting for 28.6%-30.0%. To improve future air quality, there is an urgent need to burn clean energy, improve the industrial structure, rationalize energy use, and strengthen cross-regional air pollution synergy control.
2019 年 12 月，新型冠状病毒肺炎（COVID-19）在全球爆发，中国自 2020 年 1 月 23 日起开始实施全国范围的封锁措施。这一决策对中国的空气质量产生了重大影响，特别是 PM（空气动力学等效直径小于或等于 2.5μm 的颗粒物）污染急剧下降。湖南省位于中国中东部，地形呈“马蹄形盆地”。湖南省 COVID-19 期间 PM 浓度的降低率（24.8%）明显高于全国平均水平（20.3%）。通过分析湖南省霾污染事件的变化特征和污染源，可以为政府提供更科学的对策。我们使用天气研究与预测化学模式（WRF-Chem，V4.0）来预测和模拟封锁前（2020 年 1 月 1 日至 2020 年 1 月 22 日）和封锁期间（2020 年 1 月 23 日至 2020 年 2 月 14 日）的 PM 浓度。然后，比较不同条件下的 PM 浓度，以区分气象条件和当地人类活动对 PM 污染的贡献。结果表明，PM 污染减少的最重要原因是住宅部门的人为排放，其次是工业部门，而气象因素的影响仅占 PM 的 0.5%。这是因为住宅部门的减排对七种主要污染物的减少贡献最大。最后，我们通过浓度权重轨迹分析（CWT）追踪湖南省空气质量的源和传输路径。我们发现，湖南省 PM 的外部输入主要来自东北方向输送的气团，占 28.6%-30.0%。为了改善未来的空气质量，迫切需要燃烧清洁能源，改善产业结构，合理利用能源，并加强跨区域空气污染协同控制。
