Evaluation of the nanoparticles contribution to elemental concentration in airborne particulate matter

A method for estimating the contribution of nanoparticles (NPs) to the elemental concentration in airborne particulate matter (PM) is described. The results related to size-segregated samples collected at an urban site show that significant concentrations of Sb, Cd, Pb, As, V and Sn are present in the fine fraction of PM as complex structures in which NPs are aggregated or included in other materials. These structures are easily broken in water media by the application of ultrasounds, leading to a stable suspension of insoluble NPs. The contribution of NPs can be evaluated as the difference between the inductively coupled plasma (ICP-MS) analysis before and after the elution of the stable NPs suspension from an ion exchange cartridge.