Concentrations and elemental composition of fine (PM2.5) and coarse (PM2.5-10) ambient particles,

at two sampling points located at the same urban background sites, were investigated. The points were 20 m

distant from each other and at various heights (2 and 6 m) above the ground. A dichotomous sampler, equipped

with a virtual impactor, and a cascade impactor were used to sample the dust. An X-ray fluorescence spectrometer was used in the elemental analyses. The investigations revealed heterogeneity of the spatial distribution

and the elemental composition of suspended dust at the investigated urban background site. Coarse dust, whose

concentration at 2.0 m above the ground was affected by secondary emission from roads, soil and other local

low-level sources in some periods, appeared more heterogeneous.

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.