Content of trace elements in the respirable fractions of the air particulate of urban and rural areas monitored by neutron activation analysis.

The concentrations (ng/m3) of more than 30 trace elements have been determined in the total air particulate matter and in the size-segregated fractions collected in urban, industrialized, and rural residential areas in northern Italy by means of a multistage inertial impactor with the PM10 inlet. All measurements have been carried out by instrumental neutron activation analysis, except for Pb and Cd, which have been determined by electrothermal atomic absorption spectroscopy. Analytical quality assurance procedures have been developed with special regard to blanks, reagents, and sampling. Total concentrations and the granulometric distribution found in the different locations are reported and compared.