hrvatski

Mass concentrations of water-soluble ions in PM2.5 particle fraction measured at two different sampling sites in Croatia

Daily PM2.5 samples were taken over a year 2015 at urban background sampling site (UBS) and rural background sampling site (RBS) in Croatia. Samples were analysed for water-soluble anion species (Cl-, NO3-, SO42-) and cation species (Na+, NH4+, K+, Mg2+, Ca2+), to investigate the relationship between pollutant mass concentrations, contribution of measured species to PM2.5 mass and the prediction of the pollutant sources. Mass concentrations of PM2.5 particle fraction were determined by gravimetry according to the standard HRN EN 12341:2014 (EN 12341:2014). Water-soluble ionic species were analysed using Thermo Scientific – ICS 5000 Capillary ion chromatography. PM2.5 mass concentration was significantly influenced by the season, reaching their high values in the winter. Annual average PM2.5 mass concentration measured at urban background site and rural background site were 21.4 μg m-3 and 9.4 μg m-3, respectively. The annual average ion mass concentrations at UBS and RBS followed the order SO42- > NO3- > NH4+ > K+ > Ca2+ > Cl- > Na+ > Mg2+ and SO42- > NH4+ > NO3- > K+ > Ca2+ > Mg2+ > Na+ > Cl-, respectively, contributed 28.6% and 34.8% to the overall PM2.5 mass, respectively. Annual average mass ratios of (NO3-)/(SO42-) obtained in PM2.5 at UBS and RBS were 0.85 and 0.26, respectively, indicating that mobile source emission was an important contributor to particle mass at UBS.

air pollution ; sampling site ; airborne particle ; anion species ; cation species

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