Investigation of temporal and spatial variations in atmospheric concentrations of PCDDs and PCDFs in Istanbul Gulten Gunes ⁎, Arslan Saral, Hakan Celikten, S. Levent Kuzu, Selami Demir, Nihan Uygur Yildiz Technical University, Department of Environmental Engineering, Esenler, 34220 Istanbul, Turkey HIGHLIGHTS • Motor vehicle emissions and other combustions were detected as principal sources of PCDD/F. • Concentration of PCDD/F compounds showed significant temporal variation. • Concentrations of furan congeners were higher than that of dioxin congeners. abstract article info Article history: Received 28 July 2013 Received in revised form 26 October 2013 Accepted 26 October 2013 Available online 17 December 2013 Keywords: Polichlorinated dibenzodioxins Polychlorinated dibenzofurans Persistent organic pollutants Toxic air pollutants Air quality In this study, temporal and spatial variations of the atmospheric concentrations of polychlorinated-p-dibenzo dioxin (PCDDs) and polychlorinated dibenzofuran (PCDFs) congeners were investigated in Istanbul at three different locations. The highest average concentration (3481 fg/m 3 ) was observed at the sampling location which is characterized by mixed source groups during colder months. The lowest average concentration (749 fg/m 3 ) was observed at sampling station which is characterized by semi-urban characteristics. ∑PCDD/F concentration showed seasonal variation in this study. The highest average concentration was determined to be 4373 fg/m 3 in winter while the lowest average concentration was determined to be 498 fg/m 3 in summer. © 2013 Elsevier B.V. All rights reserved. 1. Introductıon Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are ubiquitous persistent organic pollutants (POPs) (Jones and de Voogt, 1999; UNEP, 2009). They are produced as unwanted byproducts from the natural and antropogenic processes (UNEP, 2002) such as solid waste incinerators (Olie et al., 1977), metallurgical processes (Buekens et al., 2001; Anderson and Fisher, 2002; Quaß et al., 2004), iron and steel factories (Anderson and Fisher, 2002; Wang et al., 2003; Aries et al., 2006), automobile emissions (Marklund et al., 1987), steel mills (Tysklind et al., 1989) and chemical production processes (Hutzinger et al., 1985). They can be transported over long distances in the atmosphere and stored by wet/dry deposition mechanisms in all envi- ronmental systems such as surface water sources, soil, sediment, biota urban/rural areas, remote areas and polar regions (Hutzinger, 1985; Jones and de Voogt, 1999; Lohmann and Jones, 1998; Lohmann et al., 1999; Schlabach et al., 1996; Lee and Jones, 1999; Jimenez et al., 2000; Cohen et al., 2002; Corsolini et al., 2002; Hilscherova et al., 2003; Minh et al., 2003). They can bioaccumulate in the food chains (Van der Oost et al., 2003) and cause serious health effects in humans and wildlife (WHO, 1997) due to their resistant structure against photolitic, chemical and biological degradation processes. Therefore, ambient air monitoring studies were carried out by several researchers to determine their atmospheric concentrations and worldwide envi- ronmental behaviour. According to these studies, atmospheric con- centrations of PCDD/F compounds fluctuate largely for urban areas (Aristizábal et al., 2011; Li et al., 2008; Menichini et al., 2007; Lee et al., 2007). Several factors such as meteorology, topography, cli- mate, source characteristics, and degradation processes affect PCDD/F concentrations in the atmosphere (Alcock and Jones, 1996; Abad et al., 1997; Wevers et al., 1993). In addition, in this study, very fluctuating concentrations of PCDDs and PCDFs were observed for different loca- tions of Istanbul. Science of the Total Environment 488–489 (2014) 469–474 ⁎ Corresponding author at: Yıldız Technical University, Faculty of Civil Engineering, Department of Environmental Engineering, 34220, Esenler, İstanbul, Turkey. Tel.: +90 212 383 53 68. E-mail addresses: g.gunes18@gmail.com (G. Gunes), saral@yildiz.edu.tr (A. Saral), celikten@hotmail.com (H. Celikten), skuzu@yildiz.edu.tr (S.L. Kuzu), seldemir@yildiz.edu.tr (S. Demir), uygur.n@gmail.com (N. Uygur). 0048-9697/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.scitotenv.2013.10.094 Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv