PM SOURCE SIGNATURE USING SIMULTANEOUS MEASUREMENTS OF PM10, PM2.5 AND PM1 CHEMICAL TRACER CONCENTRATIONS

The study aims to identify the source signature of the particulate matter using the ratios between the chemical tracer (Tr) concentrations (i.e., Al, Ca, Cl, Fe, K, Mg, Na, NH4+, Ni, NO3-, Si, SO4 2-, Sr, Ti and V) content in PM10, PM2.5 and PM1 simultaneous measurements. Studies regarding the tracer concentrations of PM10, PM2.5 and PM1 were considered and the corresponding ratios (i.e. PM1(Tr)/PM10(Tr), PM2.5(Tr)/PM10(Tr) and (PM2.5(Tr)-PM1(Tr))/(PM10(Tr) -PM1(Tr))) were calculated and displayed using a dedicated triangular diagram. Results point out that the data relating to Al, Ca, Fe, Si, Sr and Ti (tracers mainly attributed to crustal sources) and to Cl, Mg and Na (tracers mainly related as sea-salt sources) are usually displayed towards the lower right region of the triangular diagram, where the tracer concentrations of the coarse size fraction are larger than the tracer concentrations of the fine and submicrometric size fractions. The data corresponding to Ni and V (tracers generally attributed to combustion sources) are displayed towards the upper region of the triangular diagram, where the tracer concentrations of the fine and submicrometric size fractions are larger than the tracer concentrations of the coarse size fraction. The tracer concentrations of the intermodal size fraction may not be negligible with respect to the tracer concentrations of coarse and submicrometric size fractions in this region. Finally, the data corresponding to tracers with more than one characteristic source, such as K (tracer interpreted as city dust and biomass burning) and SO4- (tracer related to combustion sources, secondary aerosols and long-range transport combined with NH4+ and NO3-) may be displayed on different regions of the triangular diagram, depending on their different emission sources. Therefore, the triangular diagram can be useful for grouping tracers on the basis of their characteristic source signature.