geo-accumulation index

heavy metal

spatial distribution

ecological risk

atmospheric particulate pollution

source

Heavy metals contamination of air

To investigate ecological risks and spatial distributions of heavy metals in atmospheric particles in the Beijing urban area, atmospheric dust was collected from 62 sites and 12 heavy metals in their <63 μm fractions were measured. Results indicate that V, Cr, Mn, Co, Ni, and Ba in the dust are basically unpolluted by human activities; whereas Cu, Zn, As, Cd, Sb, and Pb are moderately to heavily polluted. These metals (not including Ba) in most dust show a high ecological risk (RI = 809 ±585, ranging 291-4,848), predominantly contributed by Cd (71%) and Sb (14%). Relatively higher risks mainly occur in the eastern and northwestern urban areas. The high risks in the east are caused mainly by Cd pollution associated with coal-burning and industrial and traffic activities, while those in the northwest are caused mainly by Sb pollution associated with point pollution sources and Cd pollution from traffic activity. This is significant for controlling atmospheric heavy metal pollution over the Beijing urban area and investigating atmospheric metal pollution in other cities.