The variations of concentrations, profilies and possible sources of metals and polycyclic aromatic hydrocarbons in PM10 from Lanzhou, China

Metals and polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants in airborne particulate matter. In order to better understand the concentrations and origins of metals and PAHs bound to particulate matter in Lanzhou city in northwest China, six metals (Cu, Zn, Ni, Pb, Cd, and Cr) and 16 selected PAHs in 108 part iculate matter samples were quantified by inductively coupled plasma/mass spectrometry (ICP-MS) and gas chromatography/mass spectrometry. Results demonstrated that metals and PAHs in the ambient air of Lanzhou city showed regional and seasonal trends, and their concentrations were higher than those in several other Asian and European cities. The high molecular weight PAHs in winter were higher than in summer in both Xigu District and Yuzhong town. The principle components analysis (PCA) method was applied to analyze the sources of metals bound to particulate matters (PM2.5, PM10, TSP) and PAHs bound to PM10, and results showed that vehicle emissions, coal combustion, and oil combustion were probably the main sources of metal and PAHs in Lanzhou PM.