engleski

CHARACTERISATION OF MAJOR ACIDIC ANIONS IN TSP AND PM10 IN ZAGREB AIR

Twenty-four-hour samples of total suspended particles TSP, and PM10 particle fraction in Zagreb air were collected continuously at one measuring site in 2004. Samples of TSP and PM10 were collected from approximately 100 m3 of ambient air. Mass concentrations of TSP and PM10 fraction were determined by gravimetry. Acidic anions (chloride, nitrate and sulphate) were analysed using suppressed conductometric detection ion chromatography. Annual average mass concentrations were: 43.9 &micro ; g m-3 for TSP and 36.2 &micro ; g m-3 for PM10. The annual average mass concentrations of the investigated anions followed the order chloride < nitrate < sulphate. Their concentrations in TSP were 0.71 &micro ; g m-3, 5.30 &micro ; g m-3 and 6.29 &micro ; g m-3, respectively, and accounted for about 1.68%, 12.06% and 14.70% of total TSP mass. In PM10 the annual average mass concentrations of the investigated anions also followed the order chloride < nitrate < sulphate. Their concentrations in PM10 were 0.49 &micro ; g m-3, 4.70 &micro ; g m-3 and 6.64 &micro ; g m-3, respectively, and accounted for about 1.35%, 12.93% and 18.76% of total PM10 mass. Significant correlations were obtained between TSP and investigated anions and between PM10 and investigated anions, the latter showing a higher correlation coefficient. The annual average mass ratio of (NO3-)/(SO42-) obtained in TSP and PM10 was > 0.8, which suggests that mobile source emission was an important contributor to particle mass.

chlorides; nitrates; sulphates; source emission; ion chromatography

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