Emissions of polybrominated diphenyl ethers (PBDEs) in Zurich, Switzerland, determined by a combination of measurements and modeling Christian Bogdal a,⇑ , Zhanyun Wang a , Andreas M. Buser a , Martin Scheringer a , Andreas C. Gerecke b , Peter Schmid b , Claudia E. Müller b,1 , Matthew MacLeod c , Konrad Hungerbühler a a Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland b Empa, Swiss Federal Laboratories for Materials Testing and Research, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland c Department of Applied Environmental Science, Stockholm University, SE 106 91 Stockholm, Sweden highlights  PBDE measurements in ambient air in Zurich, Switzerland, show predominantly BDE 47 and BDE 209.  PBDE concentrations in air in Zurich, Switzerland, are on the upper end of concentrations usually observed in urban areas.  A multi-media fate model was applied to back-calculate atmospheric emissions of PBDEs.  Emission estimates show hardly any seasonality and are similar to emissions reported in literature. article info Article history: Received 14 October 2013 Received in revised form 16 December 2013 Accepted 21 December 2013 Available online xxxx Keywords: Brominated flame retardants Polybrominated diphenyl ethers Atmospheric emissions Ambient air Source strength abstract Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants but they are of con- cern and are currently being phased-out because of their environmentally hazardous properties and their potential to cause adverse health effects. We analyzed PBDEs in Zurich, Switzerland, and applied a multi- media environmental fate model to back-calculate the rate of PBDE emission to air. PBDE concentrations in ambient air were measured in summer 2010 and winter 2011 in the city center of Zurich. Concentra- tions were higher in summer (sum PBDEs 118–591 pg m 3 ) than in winter (sum PBDEs 17–151 pg m 3 ), and are on the upper end of concentrations reported in literature for urban sites with no point sources of PBDEs. The emissions derived from our measurements (summer: 53–165 lg capita 1 d 1 , winter: 25– 112 lg capita 1 d 1 ) and extrapolated to annual emissions for Switzerland (114–406 kg a 1 ) lie in the middle of ranges reported on the basis of substance flow analyses and emission inventories. The differ- ence between summer and winter emissions is small compared to the difference that would be expected from the temperature dependence of PBDE vapor pressure, which would be consistent with emissions occurring to a large extent from flame-proofed materials located indoors under nearly constant temper- ature conditions and/or emissions to air occurring by suspension of particles containing PBDEs. Com- pared to previous studies in Switzerland, concentrations and emissions of PBDEs appear to have increased during the last five years with an increasing contribution of decabromodiphenyl ether, despite the addition of PBDEs to national and international regulations. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction Polybromianted diphenyl ethers (PBDEs) are a group of chemi- cals widely used as additives to impart fire resistance in consumer products, such as furniture, textiles, and plastics, and in construc- tion materials (Alaee et al., 2003). The use of PBDEs as flame retar- dants has caused increasing concern because of their unintentional emission into the environment (de Wit, 2002; Birnbaum and Stas- kal, 2004; D’Silva et al., 2004; Kodavanti et al., 2010). PBDEs have been recognized as persistent, bioaccumulative and toxic chemi- cals and they undergo long-range atmospheric transport (de Wit et al., 2010). The lower-brominated PBDEs were manufactured under the designation ‘‘commercial pentabromodiphenyl ether (c-PentaBDE)’’, which contained mainly tri- to hepta-brominated congeners. c-PentaBDE is included in several national regulations on prohibited substances and has been banned internationally since 2009 by the Stockholm Convention on Persistent Organic 0045-6535/$ - see front matter Ó 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.chemosphere.2013.12.098 ⇑ Corresponding author. Tel.: +41 44 632 5951. E-mail address: christian.bogdal@chem.ethz.ch (C. Bogdal). 1 Current address: Department of Civil and Environmental Engineering, Stanford University, Stanford, 94305-4020 CA, USA. Chemosphere xxx (2014) xxx–xxx Contents lists available at ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere Please cite this article in press as: Bogdal, C., et al. Emissions of polybrominated diphenyl ethers (PBDEs) in Zurich, Switzerland, determined by a combination of measurements and modeling. Chemosphere (2014), http://dx.doi.org/10.1016/j.chemosphere.2013.12.098