Characterization and source estimates of primary and secondary carbonaceous aerosols at urban and suburban atmospheres of Düzce, Turkey.

Düzce is one of the cities located in the western Black Sea region of Turkey with a population of 377,610 in 2017 (TUIK, 2017). There is no satisfying scientific information available to address the contribution of primary and secondary sources of carbonaceous aerosols to the observed PM levels in the city. The main objective of the study is to determine the levels and sources of carbonaceous aerosols in PM. For this purpose, PM samples were collected at urban and suburban locations in Düzce during winter and summer season in 2015. Average summer OC and EC concentrations in the urban area were 9.5 and 1.3 μg m, respectively, while the corresponding concentrations were observed as 28.5 and 2.3 μg m, respectively for winter season. Summer mean OC and EC levels at the suburban site were 5.46 and 0.37 μg m, respectively, while those for winter were found as 6.68 and 0.61 μg m.The contributions of OC and EC to measured PM levels were found in the range of 10% to 60% and 1% to 7%, respectively, at the urban station while the associated contributions were in the range of 10% to 50% and 0.6% to 6%, respectively, at the suburban station. The concentrations measured during winter months in both areas were found to be higher than those measured during summer months. The EC tracer method was used in order to estimate the SOC contribution. The contribution of SOC concentrations to the total PM mass was found to be higher during winter in the urban area and during summer in the suburban area.