PSCF and CWT methods as a tool to identify potential sources of Be-7 and Pb-210 aerosols in Granada, Spain

This research is focused on studying the preferred source regions and the pathways of the air masses with high particulate concentrations impacting on the activity concentrations of Be-7 and Pb-210 aerosols in Granada atmosphere. For this purpose, three different source-receptor methods have been used: Cluster Analysis, Potential Source Contribution Function (PSCF), and Concentration Weighted Trajectory (CWT). Air filter samples were weekly collected and analysed in Granada university (Spain 37.177N, 3.598 W, 687m a.s.l.) during 12 years (2006-2017) for the activity concentration of Be-7, and during 5 years (2010-2014) for the one of Pb-210. The time series of the collected data indicate that the concentration of both radiotracers present a cyclical and seasonal pattern, in association with their origins and atmospheric conditions. Clustering analysis showed that the air masses arriving to Granada can be classified as: (1) tropical continental air masses coming from the Mediterranean Sea, (2) tropical and warm polar maritime air masses produced over the Atlantic Ocean, and (3) continental air masses originated over Europe and Northern Africa. The PSCF and CWT methods confirmed that the main source areas of Be-7 are located in the Atlantic coast of southern Morocco, and Northern Africa. On the other hand, southern France and the Algerian desert were found to be the main region sources of Pb-210. In addition, the Mediterranean Basin has been postulated as a strong source region for Be-7 and Pb-210. Furthermore, the PSCF and CWT models show that the regions with larger Be-7/Pb-210 ratios are located in the Atlantic Ocean, due to frequent stratospheric intrusions specially during the winter months.