SIZE-FRACTIONATED AEROSOL COMPOSITION AT GENT, BELGIUM - RESULTS FROMA ONE-YEAR STUDY

The ''Gent'' stacked filter unit (SFU) sampler was used to collect aer osols in separate coarse (2-10 mu m) and fine (<2 mu m) size fractions at an urban residential site in Gent, Belgium. The samplings were don e from May 1993 to July 1994, and two daily samples were taken per wee k. The samples were analyzed for the particulate mass (PM), black carb on (BC) and up to 29 elements. The elements were measured by PIXE and short-irradiation INAA. The crustal and sea-salt elements were predomi nantly associated with the coarse particles, but PM, the halogens Br a nd I, and the typical anthropogenic elements BC, S, V, Ni, Zn, In and Pb exhibited average FINE/COARSE ratios of over 2 (up to 7 for BC and I). The fine and PM10 median concentrations were compared with median levels in the respirable size fraction (<5 mu m), as measured at the s ame site in fall 1986. Overall, the airborne particulate element level s did not seem to have changed much since 1986. Notable exceptions wer e Pr and Pb, which were reduced to one third of the 1986 levels, but b oth elements were still predominantly attributable to automotive emiss ions. The fine and coarse multielemental data sets were subjected to m ultivariate receptor modelling, and the results were compared with the receptor model results from the 1986 fall study.