Platin aus Automobilabgaskatalysatoren

We estimated ambient air concentrations of platinum by applying dispersion models as well as recent emission factors that have been derived from engine test bench experiments with three-way, monolith-type catalytic converters. Predicted concentrations in various exposure scenarios range from 4 pg/m3 (street canyon, typical conditions) up to 112 pg/m3 (express-motorway, severe conditions). These values agree well with the few measurements of platinum ambient air concentrations. Platinum es emitted from catalytic converters in very small amounts (ng/km range) and is mainly in the oxidation state 0 (elemental platinum). The nanocrystalline platinum particles are attached to microm-sized aluminium oxide particles. Whether free ultrafine platinum particles may be emitted and result in biological effects has not been studied sufficiently.