东北典型城市PM2.5浓度变化及区域输送研究

Research on PM2.5 concentration variations and regional transport in typical cities of Northeast China

摘要:

研究基于鞍山市环境监测站点2017年1月-2024年12月逐时PM2.5浓度资料以及同期的地面气象要素值，利用地面风场数据和HYSPLIT后向轨迹模型探索了鞍山市PM2.5浓度区域传输影响机制与潜在源分布。结果表明：鞍山市PM2.5逐年浓度整体呈波动下降趋势。年变化趋势呈现双“U”型特征，冬季最高、夏季最低，春冬两季的污染趋势较夏秋两季明显加重。1-8月，PM2.5质量浓度逐月降低，8-12月则逐月递增；日均浓度变化上基本呈现“双峰型”特征，峰值一般出现在上午8时和夜间22时左右，谷值出现在下午16时前后。鞍山地区PM2.5浓度受到区域输送的影响明显，在春、夏、秋季，西南方向的地面风会抬升观测的PM2.5浓度，冬季偏北方向对应较高PM2.5浓度，最大抬升来自于偏北风向。春、夏季鞍山PM2.5浓度主要受北方陆地中等距离气团及海上中等距离气团输送的影响，秋季受省内西南方向较短距离气团输送影响，冬季则主要受北方陆地中等距离气团输送及省内偏西方向较短气流影响。PM2.5的潜在源区主要分布在辽宁北部、辽宁中部城市群及辽宁南部、渤海湾区域以及内蒙古兴安盟、吉林西南部、山东半岛烟台附近区域。

Abstract:

The study is based on the hourly PM2.5 concentration data from January 2017 to December 2024 at the Anshan City environmental monitoring station, as well as the surface meteorological element values during the same period. By using surface wind field data and the HYSPLIT backward trajectory model, the study explores the regional transport impact mechanism and potential source distribution of PM2.5 concentrations in Anshan City. The results show that the annual PM2.5 concentration in Anshan City exhibits an overall fluctuating downward trend. The annual variation trend presents a double “U” shape, with the highest levels in winter and the lowest in summer, and the pollution trend in spring and winter is significantly worse than in summer and autumn. From January to August, the PM2.5 mass concentration decreases monthly, while from August to December, it increases monthly. The daily average concentration shows a “bimodal” pattern, with peaks generally occurring around 8 am and 10 pm, and troughs around 4 pm. The PM2.5 concentration in the Anshan area is significantly affected by regional transport. In spring, summer, and autumn, the surface winds from the southwest direction lift the observed PM2.5 concentration, while in winter, the northerly winds correspond to higher PM2.5 concentrations, with the maximum lift coming from the northerly direction. In spring and summer, the PM2.5 concentration in Anshan is mainly influenced by medium-distance air masses from the northern land and sea, in autumn by short-distance air mass transport from the southwest within the province, and in winter by medium-distance air mass transport from the northern land and short-distance airflow from the west within the province. The potential source areas of PM2.5 are mainly distributed in the northern part of Liaoning, the central urban agglomeration of Liaoning, the southern part of Liaoning, the Bohai Bay area, as well as the Xing’an League of Inner Mongolia, the southwestern part of Jilin, and the Yantai area near the Shandong?Peninsula.