The paper presents current reports on kinetics and mechanisms of reactions with mercury which take place in the exhaust gases, discharged from the processes of combustion of solid fuels (coals). The three main stages were considered. The first one, when thermal decomposition of Hg components takes place together with formation of elemental mercury (Hg0). The second one with homogeneous oxidation of Hg0 to Hg2+ by other active components of exhaust gases (e.g. HCl). The third one with heterogeneous reactions of gaseous mercury (the both - elemental and oxidised Hg) and solid particles of fl y ash, leading to generation of particulate-bound mercury (Hgp). Influence of exhaust components and their concentrations, temperature and retention time on the efficiency of mercury oxidation was determined. The issues concerning physical (gas-solid) and chemical speciation of mercury (fractionation Hg0-Hg2+) as well as factors which have influence on the mercury speciation in exhaust gases are discussed in detail.

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.