Atmospheric Environment 36 (2002) 5841–5851 Ambient concentrations and dry deposition fluxes of trace elements in Izmir, Turkey Mustafa Odabasi*, Aysen Muezzinoglu, Ayse Bozlaker Department of Environmental Engineering, Faculty of Engineering, Dokuz Eylul University, Kaynaklar Campus, 35160 Buca-Izmir, Turkey Received 25 March 2002; accepted 27 July 2002 Abstract Dry deposition samples were collected using a smooth surrogate surface at the Kaynaklar Campus of the Dokuz Eylul University in Izmir, Turkey. Concurrently ambient aerosol samples were collected. All samples were analyzed for anthropogenic and crustal trace elements. The average trace element concentrations and fluxes measured in this study were generally higher than those reported previously for urban and rural areas. The contribution of local terrestrial and anthropogenic sources were also investigated using enrichment factors (EFs) calculated relative to the local soil. Relatively lower EFs for ambient samples and high ambient concentrations indicated that the local soil was polluted and contributed significantly to ambient trace element concentrations. Deposition samples had higher EFs than the air samples. The EF sequences of trace elements were also different for deposition and ambient samples, probably due to the fact they have different mass median diameters and deposition velocities. The overall dry deposition velocities for trace elements calculated by dividing the particulate fluxes measured with the surrogate surfaces by ambient concentrations ranged from 0.6 (Al) to 6.2 cm s 1 (Fe). The agreement between the experimental dry deposition velocities determined in this study and the previously reported ones using similar techniques for trace elements was good. r 2002 Elsevier Science Ltd. All rights reserved. Keywords: Dry deposition; Trace elements; Airborne heavy metals; Enrichment factors; Deposition velocity; Air pollution in Izmir 1. Introduction Considerable research has been conducted to investi- gate the dry deposition of air pollutants. Among these, heavy metals are of particular interest as most of them are toxic to humans and ecosystems. Dry deposition may be particularly important near urban/industrial areas adjacent to surface waters where particle concen- trations and pollutants associated with them are relatively high (Shahin et al., 2000). In the Mediterra- nean climates of elongated hot, dry and windy periods in summer, the relative contributions of wet and dry deposition mechanisms to removal of the pollutants from the atmosphere is very important. Most of the atmospheric removal is attributed to dry deposition in such areas (Al-Momani et al., 1995). However, on dry days when winds are strong enough, already deposited material as well as the crustal materials may re-entrain with mechanisms still complicating the relationships between the soil and air. Despite its importance there is no generally accepted method to directly measure or estimate dry deposition. Current dry deposition estima- tion methods often use measured air concentrations and modeled dry deposition velocities. Since the models used to predict dry deposition velocities are complex and require information that is difficult to obtain, dry deposition fluxes are often estimated using particulate concentrations and assumed deposition velocities. *Corresponding author. Tel.: +90-232-453-1008; fax: +90- 232-453-0922. E-mail address: mustafa.odabasi@deu.edu.tr (M. Odabasi). 1352-2310/02/$-see front matter r 2002 Elsevier Science Ltd. All rights reserved. PII:S1352-2310(02)00644-1