The results revealed that these two potential sources of fire emission outflows had important impact on the Black Carbon events of Tongyu. As seen in Figure 10, high correlation coefficients between BC exceeding the average value at Tongyu and daily agricultural fire counts only appeared in the region between Jiangsu Province and Anhui Province, one heartland of rice cultivation and the most important areas of agricultural residue burning in the field in China, indicating an unneglectable source area of anthropogenic fire emission to Tongyu. The Yangtse River Delta (YRD) and its surrounding area is the most populous region in the world, and is also largely a main developing region, implying high anthropogenic emissions in the future.