24-hour samples of PM1 (submicron particles, aerodynamic diameters ≤1 μm) and PM2.5
(fine particles, aerodynamic diameters ≤ 2.5 μm) were collected at a quasi-rural area in Racibórz (1 January-
30 June 2011). The samples were analysed for carbon (organic and elemental), water-soluble ions (Na+,
NH4 +, K+, Mg2+, Ca2+, Cl-, NO3 -, SO4 2-) and concentrations of 21 elements with a carbon analyser (Sunset Laboratory Ltd.), an ion chromatograph (Herisau Metrohm AG) and an Epsilon 5 spectrometer (PANalitycal), respectively. To perform the monthly mass closure calculations for PM1 and PM2.5, chemical components were categorized into the organic matter (OM), elemental carbon (EC), secondary inorganic aerosol (SIA), crustal matter (CM), Na/K/Cl (sum of Na+, K+ and Cl- concentrations), other elements (OE) and unidentified matter (UM). The results show that the particulate matter (PM) concentrations and its chemical composition are mainly influenced by the anthropogenic emissions (coal, waste and biomass combustion in home furnaces and energy production based on hard and brown coal combustion). On the other hand, the secondary organic and inorganic (to a lesser extent) aerosols constitute a considerable part of the PM mass. The findings indicate serious problems related to the possible reduction in the fine PM concentrations in southern Poland. Even though places such as Racibórz can be formally qualified as rural sites, such areas in southern Poland do not necessarily have low PM concentrations (lower than in cities) or chemical compositions of fine particles different from those in cities.