The regional transmission characteristics as well as the local emission and external transmission contribution of fine particulate matter in the eastern North China Plain were investigated using multisource data. Himawari-8 aerosol optical depth can represent the whole layer of air pollution situation; hourly aerosol optical depth were used to reconstruct the route of fine particulate matter horizontal transmission, and the transmission speed was calculated and compared with the near-surface wind speed. A case study conducted on 22 September 2019 showed the pollutant was mainly transmitted from Tangshan to Dezhou, and the transmission speed was greater than the near-surface wind speed. We also found that pollution air mass had 2–3 h of diffusion delay in the near-surface pollutant monitoring results. In addition, the vertical diffusion of pollution mainly occurred at low altitude below 1.8 km. The contribution of local emission and external transmission was inferred in this study with the help of the WRF-Chem model, the pollution in the northeastern portion of the study area mainly derived from local emissions, while the southwestern portion of the study area was mainly affected by external transport. Among them, the local emission accounted for 79.15% of the pollution in Tangshan, while the external transmission contributed 60.28% of the fine particulate matter concentration in Dezhou.

中文翻译：

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基于多源观测研究细颗粒物的区域传播并推断其局部/外部贡献：以华北平原东部为例

利用多源数据，研究了华北平原东部细颗粒物的区域传播特征以及局部排放和外部传播贡献。Himawari-8气溶胶的光学深度可以代表整层空气的污染状况；利用每小时气溶胶光学深度来重构细颗粒物水平传输的路径，并计算传输速度并将其与近地表风速进行比较。2019年9月22日进行的案例研究显示，污染物主要从唐山传播到德州，传播速度大于近地表风速。我们还发现，在近地表污染物监测结果中，污染空气团具有2–3 h的扩散延迟。此外，污染的垂直扩散主要发生在1.8 km以下的低空。在WRF-Chem模型的帮助下，本研究推断出局部排放和外部传播的贡献，研究区域东北部的污染主要来自局部排放，而研究区域西南部的污染主要受到影响。通过外部运输。其中，当地排放占唐山市污染的79.15％，而外部传播占德州细颗粒物浓度的60.28％。研究区域的西南部分主要受到外部运输的影响。其中，局部排放占唐山市污染的79.15％，而外部传播占德州细颗粒物浓度的60.28％。研究区域的西南部分主要受到外部运输的影响。其中，当地排放占唐山市污染的79.15％，而外部传播占德州细颗粒物浓度的60.28％。