Sources and physico-chemical characteristics of the atmospheric aerosol in Southern Norway

An intensive aerosol sampling campaign was carried out simultaneously at Birkenes and Nordmoen, southern Norway, from 11 April to 4 May 1988. Two different size segregative sampling instruments were used at each site. Parallel analysis was performed using several methods which allowed the determination of up to 45 components. The atmospheric concentrations were mostly found to be similar at the two sampling sites, which are separated by a distance of about 250 km. During long-range transport episodes, the pollutant concentrations were 20–50 times higher than during background periods. At the Birkenes site detailed information about the elemental and particle mass size distributions was obtained from Berner low-pressure impactor samples. The aerosol fine particle mode clearly shifted to larger particle sizes when the average relative humidity was higher than 80% during sampling. The average fine to total elemental concentration ratios of most elements were found to be similar for the different samplers and for the two sites, although differences between the sites occurred depending on the origin of the air masses sampled. A new approach based on the size distributions measured, the relative size distributions (RSD) method, was developed for the assessment of local and regional aerosol sources. The RSD method and conventional methods revealed local/regional sources of Mn, Zn, Pb, Bi, Br, I, Si and K. The interelemental concentration ratios in air masses of different geographical origin were studied and found to be similar in this study and in southern Sweden (Swietlicki et al., 1989) for air masses originating from the U.K.