Regional and long-range transport of aerosols at Mt. Aitana, Southeastern Spain.

More than 150 particulate matter (PM) samples with aerodynamic diameters smaller than 1 and 10µm (PM1 and PM10, respectively) were collected during an 18-month sampling campaign at Mt. Aitana (1558m a.s.l.), located in the western Mediterranean basin. PM samples were analyzed for water-soluble ions, carbonaceous species and trace metals using standard procedures. Average mass concentrations of PM1 and PM10 were, respectively, 5.0 and 13.3µgm-3. PM1 was composed mostly of organic carbon and ammonium sulfate, while nitrate and crustal elements were major components of the PM10 fraction. A significant positive correlation was determined between PM10 and mineral elements such as Ca or Fe. The study of the influence of air mass origin upon PM mass concentrations and composition showed that Saharan dust outbreaks were associated with the highest PM10 levels (24.9µgm-3 average during African events). Nitrate and crustal components were also considerably increased during these episodes, especially Ti and Fe (~190% higher compared with the average value for the whole study period). The results indicate that Ca/Ti and Ca/Fe ratios can be considered reliable indicators of Saharan dust intrusions.