Identification and source apportionment of trace elements in urban and suburban area of Ankara

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Çevre Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2017

Öğrenci: TAYEBEH GOLI

Danışman: SÜLEYMAN GÜRDAL TUNCEL

Özet:

In this study, Chemistry and Composition of Atmospheric fine aerosol particles in urban and suburban stations in Ankara are identified and generated data set are used to determine sources of fine particles, using receptor modeling. For this purpose, 24- hr aerosol samples were collected on Nuclepore filters using a ‘Stack Filter Unit’. Sampling continued for 15 months from July 2014 to October 2015. Samples were collected at two stations. One of the stations was located at Ankara university campus, which is an urban location, and the second station was located at METU campus, which can be considered as a suburban location. Collected filters were analyzed for 63 major, minor and trace elements, with atomic numbers ranging between 3 for Li and 92 for U. vi Measured concentrations elements are compared with corresponding data generated in other urban and suburban locations around the world, Turkey, and with performed studies in city of Ankara since 1975. As a result of these comparisons, average concentrations of elements are not significantly different from concentration reported in the literature. Concentrations of both crustal and pollution-derived elements decreased significantly between 1975 and 2015 in Ankara. Concentrations of elements show short- and long-term variations. Some of these variations are due to temporal variations in emissions and some due to temporal variations in meteorology. Meteorological parameters wind speed, wind direction, mixing height and ventilation coefficient strongly affect measured concentrations of elements. Relation between measured concentrations of elements did not show a meaningful relationship with wind direction at urban station, because sources were all around the station. However, relationship between measured concentrations of elements and wind direction was very clear in suburban station. Conditional probability function calculations demonstrated that Mamak area and OSTIM are two important source areas affecting composition of particles at METU. Positive matrix factorization (PMF) was used for source apportionment of elements to identify sources contributing to measured concentrations of them. This analysis indicates 6 sources for both stations; contaminated surface soil, a crustal factor, coal burning, oil combustion, diesel, and traffic for METU, and crustal factor, coal combustion, Road dust, traffic, contaminated soil, and diesel. Key Words: Source Apportionments, Trace Elements, Positive Matrix Factorization