Variation of platinum group elements (PGE) in airborne particulate matter (PM2.5) in the Beijing urban area, China: A case study of the 2014 APEC summit

Abstract

Platinum (Pt), palladium (Pd) and rhodium (Rh) are accumulating globally in the environment due to their use as catalysts to control automotive exhaust emissions. The aim of this study was to evaluate the effect of emission control measures on the changes in platinum group elements (PGE) concentrations in airborne particulate matter (atmospheric particulate mat-ter of aerodynamic diameter ≤2.5 μm, PM2.5) during the 2014 Asia-Pacific Economic Cooperation (APEC) Summit held in Beijing. Airborne samples were collected from Beijing urban areas with high volumes of traffic. Samples were treated using microwave-assisted digestion procedures, and the concentrations of PGE were determined by inductively coupled plasma mass spectrometry (ICP-MS).The PGE concentration during the APEC summit decreased by 35.13% and 35.21%, compared with before and after the summit, respectively, which were smaller than the corresponding decreases in the PM2.5 concentrations (∼53.9% and 50.5%, respectively). The results provide data regarding PGE accumulation trends in the urban atmospheric environments, which is ascribed to their use as catalysts in automotive catalytic converters. The results highlight the need to continue monitoring the accumulation of PGE, most notably Pd, in the urban atmospheric environment.