Chemical composition of wet and dust deposition in Athens, Greece

In the present study a wet/dry precipitation collector was used (Canadian MIC) to collect wet and dust deposition samples in one station in the center of the Athens basin, Greece, for the period September 1987-August 1988. Concentrations of the main cations (H+, NH4 +, Na+, K+, Ca2+ and Mg2+) and main anions (Cl-, NO3 - and SO4 2-) were determined. The analytical chemical methods were evaluated with NBS standard reference material and with rainwater samples from EMEP (European Monitoring Evaluation Programme). Statistical analyses of correlation between the concentration of chemical species and correlation diagrams between chemical species concentrations and wind directions were made in order to estimate the origin of the determined ions both in wet and dust deposition. In all samples non-marine molar sulfate concentrations exceed nitrate concentrations despite the dominance of low sulfur oil burning in the region (0.3% for domestic heating, 0.7% for industrial uses). For 37% of the samples the pH was lower than 4.5 and for 69% of samples was lower than 5.6. The wet flux of sulfur was calculated to be 0.67 gm-2yr-1. The results support the conclusion that chemical constituents in rain and dust deposition are a combination of emissions from natural and anthropogenic sources. © 1992

Chemical characterization of pm2.5 Aerosols in Athens-Greece

Atmospheric aerosols, PM2.5, were simultaneously collected in the center of Athens and in a semi-urban area of the Athens basin, using the Harvard Impactor (HI) system, from March 1995 to March 1996. 224 24-hr samples were collected. Chemical analysis of the filter samples was performed using ion chromatography (Cl−, SO42−, NO3−, Na+, K+, NH4+, Mg2+, Ca2+). In addition aerosol acidity was measured using a semi-micro electrode. No significant differences in chemical composition of particles were observed between the two sampling sites. At the city center the annual-average of non-sea-salt sulfate concentration was 85 nmoles m−3. Also the annual mean values of chloride, ammonium and sodium concentrations were 48, 88 and 71 nmoles m−3 respectively. Lower concentrations were observed for the rest of the ions. Aerosol acidity was higher at the city center, 18 nmoles m−3, compared to that observed at the semi-urban site, 14 nmoles m−3. Species concentrations were examined by season. The mean monthly concentrations of Cl−, NO3−, Ca2+ and H+ were higher in the winter. In contrast those of Mg2+ Na+ and K+, were higher in the summer and the spring, respectively. The concentrations of SO42−and NH4+ ions did not exhibit a seasonal pattern. Sulfate and ammonium ions were the predominant ionic species and their ionic ratio ranged between those of ammonium sulfate and letovicite. © 2001 Taylor & Francis Group, LLC