Polycyclic aromatic hydrocarbons on small spatial and temporalscales 1 Levels and variabilities
PAHs were measured together with inorganic air pollutants at two urban and one rural site in the Banja Luka, Bosnia and Hercegovina, whith the aim to study the spatial and temporal variabilities. Measurement uncertainty was quantified on basis of three independent side-by-side samplers, deployed at one of the sites. Levels of PAHs at the urban exceeded the rural site by more than 100 percent. The discrepancy was largely dominated by emission of 3 and 4 ring PAHs in the city, while 5 and 6 ring PAHs were more evenly distributed between city sites and the hill site. During the night a higher fraction of the semivolatile PAHs might have been stored in the soil or sorbed to surfaces. PAH patterns were undistinguishable across the three sites. However, concentrations of more particle-associated substances differed significantly between the urban sites than between one of the urban sites and the rural site (3 sigma uncertainty). Time-averaging (24 h basis) would have masked the significant inter-site differences of half of the substances which were found at different levels (4 h basis).