Size specific distribution of the atmospheric particulate PCDD/Fs, dl- PCBs and PAHs on a seasonal scale: Implications for cancer risks from inhalation C  eline Degrendele, Krzysztof Okonski, Lisa Melymuk * , Linda Landlov  a, Petr Kuku  cka, Pavel  Cupr, Jana Kl  anov  a * Masaryk University, RECETOX (Research Centre for Toxic Compounds in the Environment), Faculty of Science, Kamenice 753/5, 625 00 Brno, Czech Republic highlights graphical abstract  Seasonal size-specific concentrations were obtained for PAHs, PCDD/Fs and dl-PCBs.  Combustion-related compounds showed highest concentrations in cold seasons.  60e73% of PAHs, PCDD/Fs and dl- PCBs were associated with particles <0.95 mm.  Cancer risks from inhalation were 6.8 e41 times higher in winter than in summer. 0 0.5 1 1.5 2 Wi Sp Su Au Wi Sp Su Au Rural site Urban site ΣPCDD/Fs concentraƟons <0.49 0.49-0.95 0.95-1.5 1.5-3.0 3.0-7.2 7.2-10.0 article info Article history: Received 1 April 2014 Received in revised form 17 July 2014 Accepted 1 September 2014 Available online 2 September 2014 Keywords: Persistent organic pollutants Particle-bound Size distribution Seasonal variation Human risk assessment abstract This study presents the seasonal size distribution of particulate polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated bi- phenyls (dl-PCBs) in the atmosphere. Particles were sampled from October 2009 to October 2010 on a seasonal basis using a cascade impactor collecting six size fractions at a rural and urban site in the Brno area, Czech Republic. Higher concentrations of PAHs, PCDD/Fs and dl-PCBs were observed in cold seasons at both sites, attributed to the seasonality of the gas-particle partitioning, the increase of emissions and the lower boundary mixing layer in winter. All of the compounds showed a strong accumulation in the fine fraction, with, on average, 71% of SPAHs, 73% of SPCDD/Fs and 60% of Sdl-PCBs associated with particles <0.95 mm. The human risk assessment via inhalation was addressed and followed the same pattern as for concentrations, with 41 and 7 times higher risk in winter compared to summer at the rural and urban sites, respectively. More than 70% of cancer risks of PAHs, PCDD/Fs and dl-PCBs was associated with particles <0.95 mm. Moreover, an overestimation of the cancer risk via inhalation of up to 50% occurred when the size distribution of related compounds was not considered. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction The atmosphere plays an important role in the transport and distribution of chemical compounds around the world. Air contains particulate matter (PM) created by both anthropogenic and natural sources, such as fossil fuel combustion, road dust, wind erosion, * Corresponding authors. E-mail addresses: degrendele@recetox.muni.cz (C. Degrendele), okonski@ recetox.muni.cz (K. Okonski), melymuk@recetox.muni.cz (L. Melymuk), 106244@ mail.muni.cz (L. Landlov a), kukucka@recetox.muni.cz (P. Kuku cka), cupr@recetox. muni.cz (P.  Cupr), klanova@recetox.muni.cz (J. Kl anov a). Contents lists available at ScienceDirect Atmospheric Environment journal homepage: www.elsevier.com/locate/atmosenv http://dx.doi.org/10.1016/j.atmosenv.2014.09.001 1352-2310/© 2014 Elsevier Ltd. All rights reserved. Atmospheric Environment 98 (2014) 410e416