XPS and EPMA study of size-fractionated ambient aerosol particles collected in urban and industrial areas

Abstract

Ambient aerosol particles were studied by XPS (ESCA) and electron probe microanalysis energy‐dispersive X‐ray spectrometry (EPMA‐EDX) in a non‐destructive way. For sampling, polytetrafluoroethylene (PTFE) samplers were used in Battelle‐type cascade impactors. Sampling locations and times were: Visonta (North Hungary), at a coal‐fired power plant at two sites, 23 September 1992; Debrecen city centre, in 3 h periods as a function of daytime, 11 November 1992. From XPS the chemical states of the compounds of the particles could be identified mainly as NHx, SO42−, soot and SiO2. By XPS, correlation could be found between the nitrogen (N) and carbon (C) content of the particles of 0.5 and 1 μm size fractions. The concentration ratios of sulphur (S) distribution between the 0.5 and 1 μm particles showed higher S content in the smaller fraction. In Visonta these EDX S ratios were similar at both sites, while the XPS ratio was smaller far from the plume. In Debrecen the ratios were smaller than in Visonta with both methods. In Debrecen during the daytime periods the EDX ratios showed a maximum at the noon period, while the XPS ratios decreased. Surface enrichment of S was very changeable as a function of sampling places and time periods. The S enrichment factors changed from 1.5 to 5.5 in the 0.5 and 1 μm particle fractions. The EDX elemental (Al, Si, Cl, K, Ca, Fe, Cu, Zn) concentrations of the particles were discussed as tracers of different sources of aerosols. © 1997 John Wiley & Sons, Ltd.