Determination of Pd, Pt and Rh in airborne particulate and road dust by high-resolution ICP-MS: a preliminary investigation of the emission from automotive catalysts in the urban area of Rome

Abstract

At present there is increasing concern as regards the release of Pd, Pt and Rh, i.e., the Pt-group elements (PGEs), from catalytic converters for automotive exhaust control. A study was undertaken to investigate the concentrations of PGEs in airborne particulate matter and road dust in different sites of Rome and to compare the obtained data with airborne samples collected in 1991 (i.e., before the wide-scale adoption of car catalysts). The analytical technique employed was inductively coupled mass spectrometry (ICP-MS) combined with ultrasonic nebulization (UN). Airborne particulate matter and road dust were collected in different periods of the year both from several urban (high traffic) zones and one suburban (low traffic) site. The experimental results obtained so far point to a significant difference between the group of urban sites and the remote site. PGEs in the urban area for airborne particulate matter spanned the ranges (in pg m−3) 21.2–85.7, 7.8–38.8 and 2.2–5.8 for Pd, Pt and Rh, respectively. In road dust, the ranges (in ng g−1) were 102–504 for Pd, 14.4–62.2 for Pt and 1.9–11.1 for Rh. Moreover, a spot comparison of the data pertaining to the current sampling with those of a set of samples collected in 1991 confirms that the contribution of catalytic converters to the environmental presence of the said elements can no longer be neglected. Therefore, in consideration of the adverse effects of PGEs and the large number of cars equipped with catalytic converters, continued monitoring of the three elements in environmental media and biota should be undertaken in urban sites.