Froin January 2006 on, a continuous experiment consisting in determinations of granulometrie composition of the airborne dust has been performed in the Institute of Environmental Engineering of PAS, Zabrze. The investigations include measurements of concentrations of PM1 - the suspended in ambient air particles of the aerodynamic diameter not grater than I μm - by using the PM10 Dekali impactor. The results of twelve month measurements (January - December 2006) arc presented in the paper: the granulometrie composition of total suspended dust (PM10, PM2.5, PM1) in winter and summer at an urban background site in the Silcsian Agglomeration. Monthly and seasonal average concentrations of PM I O, PM2.5 and PM1 were computed.

Ambient concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), adsorbed on particles of PM2.5, were measured at 4 points located in Silesia and Małopolska Regions during 2004 through 2005 period. The fine dust was collected on filters at locations representing conditions of urban background, communication artery and industrial area. Distinctive differences between heating and summer season PAH concentrations were observed. The highest PM2.5 related PAH concentrations were observed in Krakow, within the effect of industrial and traffic sources, equally in summer and heating seasons. For selected cities, relations between the particular PM2.5 related PAHs were determined. The results show that contamination of the investigated PM2.5 with PAHs is considerable and comparable with that in other areas of similar degree of urbanization and industrialization.

The paper presents results of investigations carried out in 2005 at six crossroads in Zabrze. The investigations comprised determinations of vehicular traffic intensity, observations of meteorological conditions and, as a main subject, determinations of concentrations of PM2.5 and PM 10 at all observed sites. Structure of ambient aerosol in the vicinity of crossroads was compared with the structure of aerosol at a reference measuring point, located beyond effects of vehicular traffic, by determining a share of PM2.5 in PM 10 for cach site. At a selected crossroad the measurements lasted 11 days and the sampled dust was analyzed for chemical composition of surface of its particles with the use of the X-ray photoelectron spectroscopy (XPS). Both the most abundant and trace elements in the surface layer of dust sampled at the crossroads were identified.