PM2.5 Pollution in Eastern Coastal Provinces of China during winter

Abstract:

Abstract: The area of eastern coastal provinces of China is one of the most developed regions in China. Previous studies of PM_2.5 pollution were mainly focused on the Yangtze River Delta (YRD) and the Bejing-Tianjing-Heibei (BTH) region, which are respectively located in the north and south of this study area. In this study, we treated this area as a whole. Based on hourly PM_2.5 concentrations of 55 cities located in this area and meteorological fields in China, we investigated the spatial and temporal variabilities of PM_2.5 concentrations over the study area, and analyzed the relationships between PM_2.5 concentrations and weather conditions. We found that the PM_2.5 pollution did not only occur in the traditional focused regions, i.e., YRD and BTH, but also happened in the whole area. During winter, there were 49 cities with their mean concentrations exceeding the China’s national standard (75 μg/m³), in which 12 cities’ concentrations were greater than 150 μg/m³. The 12 cities are located in the southwest of Hebei and the west of Shandong provinces, including Shijiazhuang, Xingtai, Handan, Liaocheng, etc. The PM_2.5 pollution in December was more serious than the other two months. In December, there were about one third of the whole 55 cities with their monthly mean concentrations exceeding 150μg/m³. From December to February, except in the north area of BTH, the mean concentrations had a decreasing trend. Inspecting into the weather conditions, we found that there were strong relationship between the high PM_2.5 pollution and the weather condition. Generally, high PM_2.5 pollution is corresponding to a stable weather condition, and low PM_2.5 concentration is corresponding to a fast moving of cold anticyclone, indicating that the emissions of PM_2.5 and its precursors in most area are too high that once the weather condition becomes stable, the pollution comes, specially in the south of Heibei and the west of Shandong areas. We also found that there were strong impacts of air pollution from the BTH to the YRD along with the movement of cold anticyclone. This study gives a full insight into the PM_2.5 pollution in the area of eastern coastal provinces of China during winter, which would be helpful to forecast and control the PM_2.5 pollution in this area.

Keywords: PM_2.5; Winter; Eastern coastal provinces; Weather condition