ATMOSPHERIC DUST AEROSOLS IN SOFIA – ELECTRON MICROSCOPE CHARACTERIZATION AND ICE NUCLEATION PROPERTIES

Among the most important aspects of aerosol pollution study is the understanding of their role as condensation nuclei in the atmospheric processes and their influence on human health as risk inhalant particles. A detail discussion needs knowledge for quantitative description of their sources, transport, composition, size distribution and morphology, as well as laboratory and field tests of their activity. Electron microscope studies carried out by some of the authors for many years [1-3] aim the characterization of atmospheric dusts from Sofia and other representative industrial or tourist regions of Bulgaria. The present work combines the electron microscope analysis of dust particles from a busy traffic crossing of Sofia (Bulgaria) with investigations and quantitative characterization of their ice nucleation activity. All microscopic investigations in this study are performed on EPMA JXA-733 and SEM JSM-5300, JEOL. The maximum of size distribution is at particles with diameter less than 2 µm (Fig. 1a). The typical for atmospheric aerosols elements Si, Ca, Fe, Al, S, K, Cl, Ti, Mg and Na are present in the integral spectrum of this sample (Fig. 1b) as well as some metals like Mn, Cu and Zn, related to industry