Release of PCDD/F and PAH during vehicle fires in traffic tunnels

Two cars, one subway carriage and one railway coach were combusted in a tunnel. A sampling strategy, specifically developed for these “fire accidents”, was employed to investigate the release of PCDD/F and PAH. Over a distance of several hundred metres, exponential decrease of contamination with an increasing distance from the fire spots could be traced, with surface concentrations ranging at [ng/m2] and [μg/m2]. On average, between 7 and 220 μg/kg PCDD/F were detected in the debris. It is estimated that a total of between 1.9 mg (car) and 567 mg (railway coach PCDD/F were formed during the fires. As a result of the car fires, the tunnel was contaminated with approximately 13 g and 27 g of PAH (EPA, respectively. Unlike the homologue distribution patterns, the isomer distribution patterns of the PCDD/F showed good conformity. The deposition behaviour within the above-mentioned groups of substances is quite different. Fire accidents, in which vehicles are involved, have to be followed up by decontamination and waste disposal measures adapted to the contamination situation.