Source apportionment of ambient PM10 in urban areas of Wuxi, China

A total of 168 PM10 samples were collected during the year of 2005 at eight sites in the city of Wuxi in China. Fifteen chemical elements, three water-soluble ions, total carbon and organic carbon were analyzed. Six source categories were identified and their contributions to ambient PM10 in Wuxi were estimated using a nested chemical mass balance method that reduces the effects of colinearity on the chemical mass balance model. In addition, the concentrations of secondary aerosols, such as secondary organic carbon, sulfate and nitrate, were quantified. The spatially averaged PM10 was high in the spring and winter (123 μg·m−3 and low in the summer-fall (90 μg·m−3). According to the result of source apportionment, resuspended dust was the largest contributor to ambient PM10, accounting for more than 50% of the PM10 mass. Coal combustion (14.6%) and vehicle exhaust (9.4%) were also significant source categories of ambient PM10. Construction and cement dust, sulfates, secondary organic carbon, and nitrates made contributions ranging between 4.1% and 4.9%. Other source categories such as steel manufacturing dust and soil dust made low contributions to ambient PM10.