Platinum concentrations in urban airborne particles from Shanghai, China

The PM10 airborne particle samples were collected at Shanghai from December 2003 to December 2005 in order to investigate platinum contamination in the urban air. The samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results show that the average Pt concentration in the air of the center of Shanghai was 1.69 +/- 0.93 pg m(-3) that the increment of the Pt concentrations in Shanghai air was no significant from December 2003 to December 2005, and that the seasonal variations of the Pt concentrations over two years are possibly due to meteorological influences (i.e., wind and rain). The analytical results of the sixteen PM10) samples simultaneously collected at four sampling sites with different traffic intensity in Shanghai show a clear dependence between Pt concentrations and traffic intensity, which suggests that the auto exhaust is the main emission source of Pt in Shanghai air. Compared with the Pt background value of 0.54 +/- 0.03 pg m(-3), the Pt contamination in the ambient air of the centor of Shanghai is significant. However, the Pt contamination level in Shanghai air is lower than one in urban air of some cities in Europe, the United States and Japan.