Some analytical problems encountered for trace elements determination in the airborne particulate matter of urban and rural areas

The determination of trace elements TE. in airborne particulate matter collected onto filters requires an accurate evaluation of the entire analytical procedure. Since many elements have to be determined at a few milligrams of air dust at nanogram levels, possible sources of error can arise from uncontrolled parameters such as blank of the filters, sample homogeneity, pre-analytical treatment, primary and comparator standards. These potential critical points are presented here and discussed on the basis of the experience developed in our laboratory in previous studies where several TE monitoring campaigns have been performed for air particulate matter collected in urban as well as in rural residential areas of north Italy. Instrumental neutron activation analysis INAA. and electrothermal atomic absorption spectroscopy ET-AAS. have been used for the investigation of more than 30 trace elements.