Measurement of the elemental composition of deposits on Millipore filters commonly used to determine only the Total Suspended Particulate

Millipore filters are standard in the air quality monitoring stations of several towns to determine, by weighing, the Total Suspended Particulate in the atmosphere in accordance with our national law. We report in this work on the possibility of performing a multi-elemental, non-destructive analysis, using P.I.X.E. (Particle Induced X ray Emission) which gives much more information than the simple mass integral. The P.I.X.E, application to aerosol studies is well established but it involves generally the irradiation of thin, specifically made, filters. We have investigated the application to the particulate deposited on thicker Millipore filters with particular attention devoted to studying the filters internal contamination and the possibility to treat them as thin samples.