Speciation of iron in atmospheric aerosol samples

The influence of iron in the atmosphere is manifold and a function of its concentration, chemical environment, and solubility. Several analytical methods were applied for the characterization of iron in aerosol samples: for the analysis of solid aerosol samples, instrumental neutron activation analysis, energy- and wavelength-dispersive X-ray fluorescence, Mössbauer spectrometry and electron probe microanalysis were used. For the analysis of the digestion or leaching solutions, total-reflection X-ray fluorescence, atomic absorption spectrometry with flame or graphite furnace atomization and ion chromatography were applied. The bulk iron content of some urban aerosol sample was determined to be about 7% w/w, predominantly occurring as oxides with goethite as the major phase. The major fraction of the investigated aerosol originates from anthropogenic sources. Only 2% of the total iron content is soluble in an aqueous phase.