南宁市大气污染物传输路径特征及其潜在源区研究

Analysis of Air Pollutant Transmission Characteristics and Potential Source Areas in Nanning

关键词:  大气污染  轨迹聚类分析  潜在源贡献因子分析  浓度权重轨迹分析  南宁市

Key words:  air pollution  trajectory cluster analysis  Potential Source Contribution Function  Concentration Weighted Trajectory  Nanning

摘要:

识别和分析南宁市不同季节主要污染物的传输路径和潜在源区对制定大气污染防控措施至关重要。本文利用南宁市2019-2023年大气污染物浓度监测数据，对南宁市空气质量指数(AQI)进行统计分析，发现近5年南宁市空气质量持续改善，春夏季空气质量较好，秋冬季较差。使用混合单粒子拉格朗日综合轨迹模型(HYSPLIT)对气流后向轨迹进行模拟和聚类分析，发现南宁市大气污染物输送季节差异明显，其中污染较严重的秋、冬两季东北和偏东方向气流输送的污染物浓度最高，秋季东北方向的轨迹中有57.64%的轨迹为污染轨迹，冬季偏东方向上69.14%为污染轨迹，表明污染物主要输送路径为东北和偏东路径。再结合潜在源贡献因子分析(PSCF)和浓度权重轨迹分析(CWT)，显示广东沿海地区及湖南东部地区WPSCF>0.6、WCWT>70 μg/m3，是南宁市大气污染物主要源区。综上，当南宁市秋冬季风向为偏东或东北风时，建议加强空气质量监测，以预防潜在的污染事件并采取相应的防治措施。

Abstract:

Identifying and analyzing the transmission paths and potential source areas of major pollutants in different seasons in Nanning is crucial for formulating air pollution control measures. In this paper, the air quality index (AQI) of Nanning was statistically analyzed using the monitoring data of air pollutant concentrations from 2019-2023. It was found that the air quality in Nanning has been continuously improving in the past five years, with better air quality in spring and summer, and worse air quality in autumn and winter. Using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to simulate and cluster the backward trajectories of the airflow. It was found that there were obvious seasonal differences in the transport of atmospheric pollutants in Nanning, with the highest concentration of pollutants transported by northeasterly and easterly air currents during the more polluted autumn and winter seasons. 57.64% of the trajectories in the northeasterly direction in autumn being polluted and 69.14% of the polluted trajectories in the easterly direction in winter, indicating that the main pollutant transport paths were the northeasterly and easterly paths. Furthermore, combining Potential Source Contribution Function (PSCF) and Concentration Weighted Trajectory (CWT) analyses, it showed that in the coastal regions of Guangdong and the eastern portion of Hunan, the WPSCF exceeds a threshold of 0.6, while the WCWT surpasses the concentration level of 70 μg/m3. The aforementioned regions are the primary source areas of atmospheric pollutants in Nanning. In summary, when the wind direction in Nanning is easterly or northeasterly in autumn and winter, it is recommended that air quality monitoring be strengthened in order to prevent potential pollution events and take appropriate preventive and control measures.