Platinum concentrations in ambient aerosol at a coastal site in South China

With the burgeoning vehicle ownership in China, the emissions of certain trace pollutants are becoming more widespread and of more concern. We present results from the first measurements of platinum in airborne total suspended particulate matter (TSP) at a suburban (CityU) and a roadside (MK) sampling site in southern China at Hong Kong. TSP samples were taken with high volume air samplers at these sites with low and high traffic density, respectively, on a 2-day basis and were analyzed by inductively coupled plasma—dynamic reaction cell—mass spectrometry (ICP-DRC-MS). The results are similar from the use of two different isotopes: 194 and 195. The 48-h average Pt concentrations were 8.8 pg m−3 at CityU and 24.1 pg m−3 at MK, being higher at the site with greater traffic density, and were in the range from 6 to 38 pg m−3. The airborne Pt was found to be significantly correlated with vehicle tracer species (Zr and Ce) as well as with NO and NOx. The ratio Ce/Zr was the same at both sites whereas the ratios Pt/Zr and Pt/Ce were about 20% greater at the MK site, showing the different mobility of Pt, attributed to chemical and/or particle size effects.