| Abstract |
The present dissertation dealt with atmospheric samples ΡΜ10, over the region of Cyprus, collected by the Department of Labour Inspection, of the Ministry of Labour and Social Insurance of Cyprus and shipped to Environmental Chemical Processes Laboratory of the University of Crete for analysis of organic and elemental carbon, metals, and ions in order to evaluate the chemical composition of aerosols. The present work, will only present the results of the analysis of ions’ identification. The object of this study, parallel to the determination of concentrations, is the identification of the aerosols’ origins particularly ions in the Cyprus atmosphere, the process governing their presence, as well their spatial and temporal distribution. Based on the results obtained, we are able to examine the reliability and accuracy of our results, via the mass closure, which compares the results of our analysis with particulate mass.
The samples were collected in quartz filters, for 24 hours on an annual basis (January 2011 – December 2011) from three different monitor areas of Cyprus, representing different environments. Agia Marina Xyliatou, a natural background site, Nicosia, an urban site where the station is in the center of the city, in close vicinity to traffic emissions and Limassol, a suburban site in southern Cyprus. These areas were selected in order to determine the factors that influence the concentrations of chemical species. Cl-, Br-, NΟ3-, HPO4-, SO42- and C2O42- were analyzed for anions and Na+, NH4+, K+, Mg2+ and Ca2+ for cations.
For Nicosia the concentrations of particulate mass, as calculated by weighing the filters, before and after the sampling, exceed by far the limit of 40μg m-3set by the European Union, while for Limassol, the daily limit of 50μg m-3 was only exceeded four times during the year and for Agia Marina, the concentrations of particulate mass are below the permitted limit.
As expected, the measurements revealed that the concentration of ions in Nicosia, are higher than in the other two areas, due to the location of the station, at a busy traffic street. In Limassol the concentration of ions where less and in Agia Marina, a background area, without any human and industrial impacts even lower. In Nicosia, the
average of concentrations varies from 0,01 to 4.54μg m-3, same as in Limassol (0,01 to 4.54μg m-3), while for Agia Marina, the average is reduced for all ionic species and varies between 0,00 και 3,61μg m-3. SO42- and Ca2+ constitute the highest percentage of the ionic mass.
The seasonal variation of ionic mass, is almost the same with the variation of particulate mass, with the maximums for both masses to be presented at the same time, for the three areas. The variation of ions, can assist us to determine the sources that influence their concentrations, both locally and worldwide. Consequently, we can understand the impact of other regions to the eastern Mediterranean Sea with back-trajectories of air masses, based on Noaa Hysplit Model.
Therefore , the enhanced concentrations observed during Spring and to a lessen extend during Winter in the areas examined, are potentially caused because of the air masses from Africa and Middle East, that are associated with Saharan dust outbreaks. However, the concentrations in Nicosia and Limassol are higher, due to the enrichment of the same with other local, anthropogenic sources. Considering the fact that dust at Agia Marina is regional dust, its contribution accounts for 42% of total mass, while for Nicosia and Limassol, the regional dust being enhanced by the local dust accounts for 60% and 44%, respectively.
Sea salt particles consist of Na+, Cl-, Mg2+, ss-K+, ss-Ca2+ and ss-SO42- and they have an important place in the particulate mass. Their influence is more significant in Limassol, being a seaside area and the total contributions amounts to 11% of particulate mass, while for Agia Marina 10% and 7% for Nicosia.
Many different emission sources of particles and the processes governing these emissions are presented in the following sections. Pearson correlation with significance level 95%, between ionic species, is applied for the verification of such sources. Based on the results of this method, mainly moderate correlations have been observed between ions and few high correlations between Cl- and Na+, due to their sea salt origin. In addition to this, a statistical program “PCA” is applied, for the control of sources. Principal Componet Analysis (PCA) correlates the concentrations of ions with different factors. It is based on distribution of variables which are the concentrations of ionic particles. Using this method, we tried to conclude about statistical important correlations between particles and factors and finally to determine their emission sources. The results showed that fossil fuels combustions and biomass combustions as anthropogenic impacts, marine influence and crustal are the primary sources of atmosphere over Cyprus.
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Χημική σύσταση αιωρούμενων σωματιδίων στην Κύπρο
