Distribution and source of rare earth elements in PM_2.5 in Xiamen, China

Particulate matter with diameter ≤2.5 µm (PM_2.5 ) is a serious atmospheric pollutant. Composition and source analyses are essential for controlling PM_2.5 . Rare earth elements (REEs) have received little attention as a component of PM_2.5 . In the present study, PM_2.5 samples were collected in urban and suburban areas in Xiamen and analyzed for REEs. The concentration range of total REEs (∑REE) is 12.07 to 98.45 mg/kg, with a mean of 38.53 mg/kg, in urban PM_2.5 and 16.44 to 160.62 mg/kg, with a mean of 42.94 mg/kg, in suburban PM_2.5 . Light REE concentrations are higher in suburban PM_2.5 , whereas heavy REE concentrations are higher in urban PM_2.5 , implying distinct sources of REEs in urban and suburban PM_2.5 . The scatter plots of δEu-∑REE and La-Ce-Sm suggest that REEs in urban PM_2.5 originate from gasoline- and diesel-vehicle exhaust, whereas those in suburban PM_2.5 are mainly influenced by gasoline-vehicle exhaust. Environ Toxicol Chem 2017;36:3217-3222. © 2017 SETAC.