engleski

Ionic composition of PM2.5 particle fraction at a coastal urban background site in Croatia

The aim of this study was to determine the mass concentration and the content of water-soluble anions (Cl-, NO3 -, SO4 2-) and cations (Na+, NH4 +, K+, Mg2 +, Ca2 +) in PM2.5 particle fraction, to investigate their relationship and there contribution to the total PM2.5 mass measured at site located in Rijeka, Croatia. Rijeka is the third-largest city in Croatia at Kvarner Bay on Adriatic Sea with developed petrochemical and metal industry, shipyards, oil refining and transportation especially maritime. Measuring site is a part of Croatian monitoring network for air quality classified as urban background site. Daily samples of PM2.5 particle fraction were collected over a year 2017 on PTFE filters using the low volume sampler Sven Leckel SEQ 47/50. Mass concentration of PM2.5 particle fraction was determined by gravimetric according to the standard HRN EN 12341:2014 (EN 12341:2014). The content of water-soluble inorganic anions and cations were determined using Thermo Scientific ICS-5000 capillary ion chromatograph. Results show that annual average PM2.5 mass concentration was 9.65 μg/m3 and didn't exceed limit value of 25 μg/m3 given by the Regulation on the level of pollutants in air (OG No. 117/12). The annual average mass concentrations of ions in PM2.5 particle fraction was in order SO4 2- > NH4 + > NO3 - > Ca2+ > K+ > Na+ > Cl- > Mg2+. Contribution of total anion mass and cation mass to the total PM2.5 mass were 25.4% and 12.8%, respectively. Contribution of each anion mass to the total anion mass were 84.8% , 14.2% and 0.9% for SO4 2-, NO3 - and Clrespectively, while contribution of each cation mass to the total cation mass were 6.6% , 72% , 6.2% , 1% and 13.3% for Na+, NH4 +, K+, Mg2+ and Ca2+, respectively. The prediction of the pollutant sources we ran the principal component analysis (PCA) which was performed using the statistical packages STATISTICA 13.0. After varimax rotation, the obtained four principal component factors were found to account for 86% of the variance. Factor loadings > 0.7 were considered significant.

Measuring site ; Anions ; Cations ; PCA

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