Characterization of individual aerosol particles from the eruption of Lonquimay volcano in Chile

A set of aerosol samples collected during major volcanic activities around the Chilean site Lonquimay in the years 1988–1990 has been subjected to measurements in conventional and microPIXE modes in the Debrecen institute. The aim of the study was the completion of the earlier results with comparative PIXE data and microPIXE measurements for the characterization of individual particles. Results have been obtained on separate particles in terms of their elemental composition, on separate particle groups of different composition by statistical dissimilarity analysis. Si/Al and K/Si elemental ratios have been used for a comparison with published data from other volcanic locations.     

Experimental and theoretical calibration of a PIXE setup for K and L X-rays

K and L line calibration has been performed for a PIXE setup by the independent use of experimental and theoretical methods. In the former case, thin film standards of known thicknesses were applied, while in the latter one cross section values were derived from different theoretical models.Programs REV5S and PIXEKL developed here were used for spectrum evaluation and concentration determination, respectively. They proved to be reliable and especially appropriate for routine serial evaluation of spectra measured on samples of nearly identical matrices.As a result of the work, an accurate calibration of the setup has been obtained and it was shown that experimental and theoretical techniques used lead to calibration curves which fit each other reasonably well.     

Identification and characterization of fine and coarse particulate matter sources in a middle-European urban environment

In this work a source apportionment study is presented which aimed to characterize the PM_2.5 and PM_2.5–10 sources in the urban area of Debrecen, East-Hungary by using streaker samples, IBA methods and positive matrix factorization (PMF) analysis.Samples of fine (PM_2.5) and coarse (PM_2.5–10) urban particulate matter were collected with 2 h time resolution in the frame of five sampling campaigns during 2007–2009 in different seasons in the downtown of Debrecen.Elemental concentrations from Al to Pb of over 1000 samples were obtained by particle induced X-ray emission (PIXE); concentrations of black carbon (BC) were determined with a smoke stain reflectometer. On this data base source apportionment was carried out by using the PMF method.Seven factors were identified for both size fractions, including soil dust, traffic, secondary aerosol – sulphates, domestic heating, oil combustion, agriculture and an unknown factor enriched with chlorine. Seasonal and daily variation of the different factors was studied as well as their dependence on meteorological parameters.Besides determining the time patterns characteristic to the city, several emission episodes were identified including a Saharan dust intrusion on 21st–24th May, 2008.     

Ion beam microanalysis of individual aerosol particles originating from Saharan dust episodes observed in Debrecen,Hungary

Approximately 50 episodes of Saharan dust intrusion have been observed by PIXE in the atmosphere of Debrecen, Hungary since 1991 [I. Borbély-Kiss, Á.Z. Kiss, E Koltay, Gy. Szabó, L. Bozó, J. Aerosol Sci. 35 (2004) 1205]. In order to separate dust particles of Saharan origin from local sources, and to follow the formation, ageing and evolution of particles originating from long range transport processes, individual dust particle analysis was carried out on the Debrecen ion microprobe.The samples were collected on polycarbonate filters at a rural site 50 km from Debrecen during the Saharan sand plume in November 1996.Quantitative elemental concentrations for elements Z ? 6 were determined using PIXE–PIXE and STIM analytical methods. Saharan dust particles were selected on the base of characteristic elemental ratios like Ti/Ca, Ti/Fe and Al/Ca. Major and trace element content and possible chemical composition of the selected particles were determined.Single particle analysis of Saharan dust particles will lead to a better understanding of their formation process during transport.     

Composition of urban and rural aerosol samples collected in the Great Hungarian Plain

Urban and rural atmospheric aerosol samples have been collected simultaneously during 1997 in the Great Hungarian Plain. The elemental composition of the coarse and fine mode aerosol have been determined by the Proton-Induced X-ray Emission method. From the observed elemental concentrations, seasonal variations and variations with the wind sector distributions were found for separate elements. Principal component analyses gave four factors in urban aerosol, and three factors in the rural one. The order of the factors in the coarse mode aerosol is different from the order, found in the fine mode.     

Study of aerosols collected in a speleotherapeutic cave situated below Budapest, Hungary

The Szeml hegy-cave is one of the well-known hydrothermal caves of the Rózsadomb area of Budapest, which have been used for speleotherapy of respiratory diseases for years. It is known from the periodically changing airborne radon activity concentration data, that airflow of seasonally reversed direction are formed along the cave passages and fissures due to the temperature difference between the surface and cave air. This means that an intensive interaction takes place between the cave and its environment. The pollution of nearby waters and the urban atmospheric air represents a real danger for these caves below Buda, which recently became the part of the UNESCO World Heritage. The study of cave aerosols should be very important from the point of view of either the control possibilities of the environmental impact or speleotherapy, and probably helps in getting acquainted with the cave-forming processes. In this work we applied our standard aerosol sampling method to the high-humidity environment of the caves, and we studied the elemental composition, size fractionation as well as the spatial distribution and the seasonal variation of cave aerosols. Thanks to the sensitivity of PIXE traces of anthropogenic pollution of the Budapest air are shown in the Szeml hegy-cave. Measured elemental concentrations remained less than one-tenth the air quality standard valid for the increasingly protected areas.