Highly time- and size-resolved fingerprint analysis and risk assessment of airborne elements in a megacity in the Yangtze River Delta, China.

The frequent haze episodes in the Yangtze River Delta (YRD) of China have been of great public concern due to the high risks to human health. Therefore, a better understanding of the sources and characteristics of particulate matters (PM) and associated elements is crucial and urgent for haze controlling. In this study, air particulates were collected from six different functional areas in a megacity of the YRD, China in early winter of 2012. Highly time- and size-resolved analysis of PM-elements was conducted to trace their sources. Our results showed that the main donors to particulate elements were crustal dust, followed by traffic and industrial influences due to the mixed residential, commercial and industrial zones at most sites. Anthropogenesis contributed more to the sources of finer particles and associated elements than those of coarser ones. Besides the local emission sources, meteorological conditions also affected the distribution patterns of ambient elements. Furthermore, the risks of hazard metals in PM2.5 and PM1.0 to human health were estimated. The highest non-carcinogenic and carcinogenic risks were observed at urban living quarter (ULQ) and eco-industrial park (EIP), respectively. In addition, the general risks at rural living quarters (RLQ) were the lowest. Results from this study may provide valuable information for air pollution control and management in the YRD, China.