Analysis of lead and cadmium concentrations in the air comparing concentration values difference between heating and summer seasons was carried out in the paper. Relevant procedure was adopted to find out if the concentration values in these two seasons differed in kind. The concentration seasonal difference was not found in case of cadmium but it was found for lead. It was proved in further part of the paper that the analysed mean 24-hour Pb concentrations for heating season could be presented as a sum of the mean annual background concentration and the concentration values resulted from Pb emission from sources active only in the heating season. In the area where the measurements were carried out residential furnaces were this kind of sources. The cumulative distribution function of the mean 24-hour lead concentration resulted from Pb emissions in the heating season was determined using two-layer neural network. It was found according to this approach that Pb concentration as the result of Pb emissions from residential furnaces, for 145 days, i.e. 80% of the heating season period, were at least two-fold lower than the lead concentration values as the result of Pb emission from the all year active sources. Only for 14 days emission sources active in the heating season produced Pb concentrations higher than Pb mean annual background concentration.

Leaded and unleaded petrol samples as well as diesel oil samples were analysed lo determine Cd. Cr. Cu, Ni, Pb, Zn and As concentrations. In order lo obtain low detection limits new method of samples preparation was used. The fuel samples were dissolved in hydroraffinate which was the crude oil fraction obtained as a result of atmospheric distillation in the range of I 50---250°C. The obtained data on the metal concentrations in the investigated fuels allow determining the following emission factors of traffic fuels consumption processes [mg/kg fuel]: leaded and unleaded petrol - Cr - 0,5; Cu - 0,3; Ni - 0.5; Pb - 50 (leaded): Pb - 5 (unleaded); diesel fuel - Cd - 0,05: Cu - 0,3: Ni - 0.5. It was found in the investigations that traffic fuels consumption is not the source of Zn and As emission. The same refers to Cd emission in case of leaded and unleaded petrol consumption. On the basis of the identified emission factors Pb emission from traffic in Poland for years 1980---1999 as well as Cd, Cr, Cu and Ni emission for I 999 were assessed. The following emission in 1999 was determined as a result of the assessment [Mg]: Cd - 0,3: Cr - 2,9: Cu - 3,5 and Ni - 5,9. Emission of Pbu, was 237.6 Mg and Pb1.,w 79,2 Mg. These emissions were also compared with the total metal emissions in Poland.

Size distribution of particulate matter (PM) emitted from coal combustion in residential furnaces as well as emission of Hg, Zn, Pb and Cu were investigated. The metals emission was characterised by partition factors K. The factor expresses the distribution of metal streams between the feed coal and its combustion products emitted to the atmosphere. The values of factors K for Zn, Pb and Cu were 0.59, 0.33 and 0.34 respectively; the relevant variance coefficients were 37, 46 and 44%. Much better variance coefficient of factor K (17%) appeared in the case of mercury. It was found that 52% of Hg in feed coal was emitted to the air in gaseous form. Particulate matter emission from 7 coal combustion sources was investigated and fine particles were found as the main fraction. About 76% of PM were emitted as the size fractions up to 12 μm. The share of size fractions between 12-29 μm was 9%. It means that the impact of PM emission from residential furnaces is not of local scale but the particles containing heavy metals can be transported on long distances in the atmosphere.