engleski

Sampling and analysis of PAHs in Zagreb air

Polycyclic aromatic hydrocarbons (PAHs) are a product of incomplete combustion of fossil fuels and other organic materials. They consist of two or more fused aromatic rings. PAHs with fewer rings are gases, but PAHs with five and more rings are bound to particles which then move into the soil, water, sediment and vegetation, through dry or wet deposition. Benzo(a)pyrene is the most commonly measured PAH since it has always been present and used as an indicator of carcinogenic hazard in polluted environments. Samples were collected at two measuring sites, located at different part of the city of Zagreb. Measuring site A was located in the northern low-rise residential part of Zagreb with small population density, individual heating, and modest traffic. Site B was located in the southern part of the city near a busy crossroads, parking, and a garage. At both sites twenty-four hour samples of PM10 particles were collected on quartz filters with a low volume PM10 Sven Leckel sampler from about 50 m3 of air. The samplers were set at about 1.5-2 m above the ground, and about 10- 20 m away from the road. Samples were taken only on working days in the winter and summer. After collection, samples were wrapped in aluminium foil and kept in deep freeze at -18oC until analysed. The analysis was performed using a Varian Pro Star high performance liquid chromatograph (HPLC) with a fluorescence detector and programmed changes in excitation and emission wavelength to optimise selectivity and sensitivity. Samples were analysed for the following PAHs: fluoranthene (Flu), pyrene (Pyr), benzo(a)antrazene (BaA), chrysene (Chr), benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (BkF), benzo(a)pyrene (BaP), benzo(ghi)perylene (BghiP), and indeno (1, 2, 3-cd) pyrene (Ind). Average mass concentrations of all PAHs over the summer were low at both sampling sites, but all PAHs at site B were about two times higher. Average BaP mass concentrations at site A was 0.041 ng/m3 and at site B 0.073 ng/m3. In the winter, all PAHs were 2-3 times higher at site B. Average BaP mass concentrations at site A was 1.147ng/m3 and at site B 2.762 ng/m3. This investigation has shown that concentrations of all PAHs correlated with traffic intensity.

HPLC; BaP; air pollution; traffic; PM10

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