Levels and risk assessment for humans and ecosystems of platinum group elements in the airborne particles of some European cities

Traffic is the main source of platinum-group element (PGE) contamination in populated urban areas. There is increasing concern about the hazardous effects of these new pollutants for people and for other living organisms in these areas. Airborne and road dusts, as well as tree bark and grass samples were collected at locations in the European cities of Göteborg (Sweden), Madrid (Spain), Rome (Italy), Munich (Germany), Sheffield and London (UK). Today, in spite of the large number of parameters that can influence the airborne PGE content, the results obtained so far indicate significantly higher PGE levels at traffic sites compared with the rural or non-polluted zones that have been investigated (background levels). The average Pt content in airborne particles found in downtown Madrid, Göteborg and Rome is in the range 7.3–13.1 pg m&#8722;3. The ring roads of these cities have values in the range 4.1–17.7 pg m&#8722;3. In Munich, a lower Pt content was found in airborne particles (4.1 pg m&#8722;3). The same tendency has been noted for downtown Rh, with contents in the range 2.2–2.8 pg m&#8722;3, and in the range 0.8–3.0 and 0.3 pg m&#8722;3 for motorway margins in Munich. The combined results obtained using a wide-range airborne classifier (WRAC) collector and a PM-10 or virtual impactor show that Pt is associated with particles for a wide range of diameters. The smaller the particle size, the lower the Pt concentration. However, in particles <PM-10, some of the highest values correspond to the fraction