Enrichment Characteristics and Source Analysis of Metal Elements in PM₂.₅ in Autumn in Nanchang City

PM₂.₅ samples were collected in six different functional zones in Nanchang City during autumn in 2013. PM₂.₅ mass concentration and enrichment characteristics of eighteen metal elements (Mg, Al, K, Ca, Ti, V, Ba, Co, Cr, Mn, Fe, Ni, Cu, Zn, Cd, Pb, As and Hg) were analyzed. The pollution sources of the above elements in PM₂.₅ were discussed based on the results of multivariate statistical analysis. The results showed that the average daily mass concentration of PM₂.₅ during autumn in Nanchang City met the secondary standard limit (≤ 75 µg · m⁻³) of National Ambient Air Quality Standards (GB 3095-2012). The enrichment factors of Mn, Ti, Al and V were lower than 1.0, indicating that these elements were barely enriched. The enrichment factors of Fe, Cr, Co, K, Mg, Ba, Ca, Cu and As ranged from 1.7 to 7.8, suggesting the influence of both natural sources and anthropogenic sources. Hg, Zn, Pb, Ni and Cd were obviously affected by anthropogenic emissions since their enrichment factors ranged from 21. 9 to 481.2. The combined results of correlation analysis, principal components analysis and cluster analysis revealed the pollution sources of these metals in PM₂.₅: Mg, K, Al, Ca and Ti mainly came from natural soil and building material dust; As and Hg were mainly from coal combustion; Ba, Ni and Mn were mainly from industrial emission of metal smelting; V, Cu, Fe, Cd, Pb, Cr and Co mainly came from traffic sources; Zn was influenced by metal smelting and coal burning.