Trace elements in PM2.5 shed light on Saharan dust incursions over the Munich airshed in spring 2022†

The influence of a prolonged Saharan Dust event across Europe and specifically in Munich (Germany) in March 2022 was detected and analyzed in detail. The event arose from a sequence of Saharan Dust incursions intertwined with a stagnation in the regional circulation leading to the persistence of a mineral dust plume for several weeks over the region. Trace element and meteorological data were collected. Enrichment factors, size distribution analyses, and multivariate techniques such as Varimax and Self-Organizing Maps (SOM) were applied to highlight the influence of Saharan Dusts and to evaluate the pollution sources in Munich municipality. The overall results revealed how the Munich airshed was clearly affected by long-distance mineral dusts from the North African desert, that increased the concentrations of natural (e.g. Al, Mg, Ca) and anthropogenic (e.g. Sb, Mo, Pb) elements based on the different paths followed by the dusts. Moreover, the chemometric analyses revealed a range of well-defined local anthropogenic emission sources including road traffic, energy production by coal combustion (S and Se), traffic (Cu, Sb), and waste incineration (Zn).