Spatial variation and provenance of atmospheric trace elemental deposition in Beijing

Özet

Atmospheric dry deposition samples were collected in urban and suburban areas of Beijing during a coalburningperiod. Chemical characteristics of lanthanoid elements (LaeLu) and five heavy metals (Cr, Co,Mo, Cd, and Pb) were analyzed to determine the variation in spatial scale and deposition provenances.Factor analysis and ternary diagrams were used to identify principle pollution sources. The LaCeSmternary diagram was used to identify oil refineries using fluid catalytic converters and steel plants, butcould not differentiate crustal materials. Lanthanoid characteristic parameters showed similarity betweendeposition and soil in the local and southwest area in the vicinity of Beijing. Analysis of the fiveheavy metals enabled discrimination of contaminants originating from human activities. Cd, Pb, and Mowere found to originate from vehicular traffic, whereas Co and Cr originated from industrial emissionsand coal combustion. Discriminant analysis established the causes of spatial variation. The result showsthat Co, Mo, and Pb can mark the differences between urban and suburban sites. From the PbMoCo plot,it was inferred that the different chemical characters are mainly due to the differing origins of depositions.Deposition samples in suburban areas are principally influenced by soil, chimney soot, andfertilizer, whereas those in urban area are mainly affected by traffic emissions.