Partic. vol. 11 no. 1 pp. 63-69 (February 2013)
doi: 10.1016/j.partic.2012.08.002

Elemental compositions of PM_2.5 and TSP in Lijiang, southeastern edge of Tibetan Plateau during pre-monsoon period

Ningning Zhang^{a, b} Junji Cao^{a, c, *} Hongmei Xu^a Chongshu Zhu^a

cao@loess.llqg.ac.cn

Abstract

PM_2.5 and total suspended particulate (TSP) samples were collected at Lijiang, southeastern Tibetan Plateau, China. Sixteen elements (Al, Si, S, K, Ca, Cr, Mn, Ti, Fe, Ni, Zn, As, Br, Sb, Pb and Cu) were analyzed to investigate their elemental compositions during the pre-monsoon period. The results showed that Ca was the most abundant element in both PM_2.5 and TSP samples. The enrichment factors (EFs) of Si, Ti, Ca, Fe, K and Mn were all below 10 for both PM_2.5 and TSP, and these elements also had lower PM_2.5/TSP ratios (0.32–0.34), suggesting that they were mainly derived from crustal sources. Elements Cu, Zn, S, Br and Sb showed strong enrichment in PM_2.5 and TSP samples, with their PM_2.5/TSP ratios ranging from 0.66 to 0.97, indicating that they were enriched in the fine fractions and influenced by anthropogenic sources. Analysis of the wind field at 500 hPa and calculations of back trajectories indicated that Al, Si, Ca, Ti, Cr, Mn and Fe can be influenced by transport from northwestern China during the dust-storm season, and that S, K, Ni, Br and Pb reached high concentrations during westerly transport from south Asia. Combined with the principle component analysis and correlation analysis, elements of PM_2.5 samples were mainly from crustal sources, biomass burning emissions and regional traffic-related sources.

Graphical abstract

Keywords

Elements; Enrichment factors; Pre-monsoon; Lijiang