engleski

New Insight into Sahara Dust Transport to Croatia

An evaluation of source apportionment analysis results was performed on daily PM2.5 samples collected at an urban-background monitoring station in Zagreb, Croatia during a two-year period (2014-2105). Samples were collected on PTFE 47 mm diameter filters using a Sven Leckel SEQ47/50 sampler. PM2.5 concentrations were determined using the EN12341 gravimetric method, while the elemental composition of the samples was analysed by ED XRF method, using EPSILON5, PanAnalytical equipment. Among others, one strong factor was found, showing little influence on the total mass of samples and defined by Al, Ca, Fe, Si and Ti, with factor contributions of 56%, 45%, 26%, 99% and 65%, respectively. This source was connected to mineral or soil dust. Further analysis of back trajectories obtained by the HYSPLIT software developed at the Air Resources Laboratory, NOAA, USA, showed together with local, a contribution from long range transport of different origins. It was observed that each occurrence (around 40 by year) of the back trajectories coming from the coast or inlands of North Africa was registered in Zagreb as a contribution to this factor, representing transport of Sahara dust to Central Europe. Opposite to the rare events when the population can observe coloured sediment or coloured rain, most of these events could not be registered without thorough particle content analysis and subsequent modelling. The results of this investigation show us quite a different conclusion regarding the occurrence of Sahara dust in Croatia.

PM2.5; long-range transport; EDXRF; HYSPLIT

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