The aim of the study was to assess the profile of EC (elemental carbon) and OC (organic carbon) temperature fractions in PM1 and PM2.5 samples and in wet deposition samples (material collected on a filter). The research was conducted at the urban background station in Zabrze (southern Poland) in the period of Oct 2020–Oct 2021. PM samples were collected with high-volume samplers; the automatic precipitation collector NSA 181 by Eigenbrodt was used to collect the deposition samples. Concentrations of EC and OC were determined using thermal-optical method (carbon analyzer from Sunset Laboratory Inc., “eusaar_2” protocol). Regardless of the type of research material, organic carbon constituted the dominant part of the carbonaceous matter, and this dominance was more visible in the non-heating season. The profile of temperature fractions of OC and EC was clearly different for dust washed out by precipitation. Noteworthy is a much lower content of pyrolytic carbon (PC) in OC, which can be explained by the fact that PC is most often combined with the water soluble organic carbon. In addition, a high proportion of the OC3 fraction was observed, followed by OC4, which may indicate that these fractions are of a more regional origin. With regard to the EC fractions, the differences are less visible and concern, in particular, the higher share of EC4 and the lower EC2. The obtained results may be a valuable source of information about the actual status of the carbonaceous matter and its transformation in the atmosphere.

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.

Thirteen fractions of ambient dust were investigated in Zabrze, a typical urban area in the central part of Upper Silesia (Poland), during a heating season. Fifteen PAH and Cr, Mn, Co, Ni, As, Se, Cd, Pb contents of each fraction were determined. The dust was sampled with use of a cascade impactor and chemically analyzed with an energy dispersive X-ray fluorescence spectrometer (PANalytical Epsilon 5) and a gas chromatograph with a flame ionisation detector (Perkin Elmer Clarus 500). The concentrations of PM1 and the PM1-related PAH and elements were much higher than the ones of the coarse dust (PM2.5-10) and the substances contained in it. The concentrations of total PAH and carcinogenic PAH were very high (the concentrations of PM1-, PM2.5-, and PM10-related BaP were 16.08, 19.19, 19.32 ng m-3, respectively). The municipal emission, resulted mainly from hard coal combustion processes, appeared to be the main factor affecting the air quality in Zabrze in winter.

The: PM2.5/PM10 ratio expresses the anthropogenic share in atmospheric dusl. Very high values or this ratio, i.e. high contribution or PM2.5 to PM10. have occurred recently in atmospheric air within European indusuializcd areas. The paper compiles results of three year pair wise measuring ofconcentrations or PM2.5 and PM2.5-PM10 and compares shares or PMM2.5 in PM10 al three urban background sites in Upper Silesia Poland I towns or Zabrze. Katowice and Częstochowa). At all the three local ions, the PM2.5/PM10 ratio nr daily conccntrations nr dust only occasionally differed considerably from the PM2.5/PM10 ratios for the seasonal and yearly concentrations that, in turn. did not differ from the PM2.5/PM10 ratios al urban sites in Europe.

Polycyclic aromatic hydrocarbons (PAI-ls) are persistent organic pollutants, ubiquitous in the whole environment. They are relatively well known and are still of interest due to their well documented carcinogenic and mutagenie properties. In ambient air of urban regions they mostly occur as adsorbed to particles of suspended dust. The richest in these compounds and therefore most hazardous to humans, fraction of dust is the fraction of the finest particles. The paper presents results of investigations of dust sampled with use of an impactor Dekati PM10 in Zabrze, a site typical of Upper Silesian conditions. While sampling, the impactor segregates sampled particles into four fractions by their aerodynamic diameters. Sixteen PAHs were determined in each fraction chromatographically. PAH content in the fraction of the finest particles, i.e. in PM1, was of particular interest.