Characterization of PM10 atmospheric aerosol at urban and urban background sites in Fuzhou city, China

Abstract

PM(10) aerosol samples were simultaneously collected at two urban and one urban background sites in Fuzhou city during two sampling campaigns in summer and winter. PM(10) mass concentrations and chemical compositions were determined. Water-soluble inorganic ions (Cl(-), NO(3)(-), SO(4)(2-), NH(4)(+), K(+), Na(+), Ca(2+), and Mg(2+)), carbonaceous species (elemental carbon and organic carbon), and elements (Al, Si, Mg, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, and Pb) were detected using ion chromatography, thermal/optical reflectance, and proton-induced X-ray emission methods, respectively. PM(10) mass concentrations, as well as most of the chemical components, were significantly increased from urban background to urban sites, which were due to enhanced anthropogenic activities in urban areas. Elements, carbonaceous species, and most of the ions were more uniformly distributed at different types of sites in winter, whereas secondary ion SO(4)(2-), NO(3)(-), and NH(4)(+) showed more evident urban-background contrast in this season. The chemical mass closure indicated that mineral dust, organic matters, and sulfate were the most abundant components in PM(10). The sum of individually measured components accounted for 86.9-97.7% of the total measured PM(10) concentration, and the discrepancy was larger in urban area than in urban background area. According to the principal component analysis-multivariate linear regression model, mineral dust, secondary inorganic ions, sea salt, and motor vehicle were mainly responsible for the PM(10) particles in Fuzhou atmosphere, and contributed 19.9%, 53.3%, 21.3%, and 5.5% of PM(10), respectively.