J.R. Morales

A study of the particulate matter PM10 composition in the atmosphere of Chillán, Chile

Inhalable particulate matter (PM10) concentrations were measured over 24-h intervals at six different urban sites in the city of Chillán from September 2001 to April 2003. Sampling locations were selected to represent central city, commercial, residential, and industrial portions of the city. Chemical composition of PM10 was performed to samples of 47 mm diameter Teflon membranes within the city of Chillán. The spatial and temporal variability of the chemical composition of PM10 was evaluated taking into account additional data from meteorology and further air pollutants. The majority of PM mass was comprised of carbon, nitrate, sulfate, ammonium, and crustal components but in different proportion on different days and at different sites. The chemical analyses showed that carbonaceous substances and crustal material were the most abundant component of PM10 during the winter and summer, respectively. The concentrations of PM10 were higher during the cold season than during the warm season. The PM10 concentrations were higher in the downtown area of the city of Chillán, where also the chemical composition was more variable due to urban traffic and other anthropogenic sources.

Contaminación del Aire Atmosférico por Material Particulado en una Ciudad Intermedia: El Caso de Chillán (Chile)

Through an analysis of the urban contamination of the city of Chillan in Chile, it is demonstrated that the increase in atmospheric pollution during autumn and winter in the city of Chillan must be considered as a problem of anthropogenic origin. This is explained mainly due to the massive use of wood for residential heating in urban areas of the city and that produces a dense smoke-type cloud during days of stable atmospheric conditions. This suggests that it is probably necessary to control wood combustion for home heating during the most critical days. Also, the increase in pollution in the center of the city indicates that decreasing the pollution level can be also done with government regulations on transport and industry. In this way only, sustainable development of medium size cities as Chillan will be facilitated, not repeating the serious problems of large polluted cities.

Analysis of aerosol particles and coarse particulate matter concentrations in Chillán, Chile, 2001-2003.

Abstract Daily particle samples were collected in Chillán, Chile, at six urban locations from September 1, 2001, through September 30, 2003. Aerosol samples were collected using monitors equipped with a Sierra Andersen 246-b cyclone inlet on Teflon filters. Average concentrations of coarse particulate matter (PM10) for the 2001–2003 period ranged from 43.4 μg/m3 to 81.8 μg/m3 across the six sites. Annual PM10 concentration levels exceeded the European Union concentration limits. Mean PM10 levels during the cold season (April through September) were more than twice as high as those observed in the warm season (October through March). Average contributions to PM10 from organic matter, soil dust, nitrate (NO3 −), elemental carbon, ammonium (NH4 +), and sulfate (SO4 2−) were 31%, 27%, 11%, 8%, 7%, and 5%, respectively. The chemical analyses indicated that carbonaceous substances were the most abundant components of PM10 in cold months, whereas crustal material was the most abundant component of PM10 during warm months. Higher concentration levels were observed in the downtown area suggesting a clear anthropogenic origin, whereas in the rural sites the source was mainly natural, such as resuspended soil dust associated with traffic on unpaved roads and agricultural activities.

Cluster analysis of elemental constituents of individual atmospheric aerosol particles from the volcanic plume of Lonquimay eruption in 1989

Aerosol samples collected around the Chilean site Lonquimay during major volcanic activities in January 1989 have been subjected to microPIXE measurements of 1 mm lateral resolution in the Debrecen Institute. Elemental concentrations relative to calcium have been determined for Al, Si, P, S, K, Sc, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, and Ba in 187 individual aerosol particles with the particle sizes between 15 mm and 1 mm. On the basis of a cluster analysis performed on the data set we defined eight clusters. Scatter plots for selected pairs of elements as Si/Al, K/Si, S/Cl, and Al/S elemental ratios that are considered as signatures characterizing types and mechanisms in volcanic eruption - have been compared with published data available in the literature for various volcanic sites.

Survival Study of Zebrafish Embryos Under Gamma Irradiation

Zebrafish embryos have interesting biological properties for the study of human diseases. The present work uses zebrafish embryos in a particular development state, to study biological effects due to gamma radiation, arising from a calibrated 60Co source. Initially, the lethal dose for fish embryos was determined and subsequent irradiations were performed at sub‐lethal doses, in order to study more subtle effects.

Captura, cuantificación y caracterización del material particulado sedimentarle en techumbres de la ciudad de Copiapó

Se realizo la caracterizacion del material particulado depositado por las empresas mineras de la ciudad de Copiapo en los relaves de mayor impacto ambiental, asi como la concentracion de algunos de los elementos presentes en ellos. Simultaneamente, se procedio a capturar, cuantificar y caracterizar el material particulado suspendido y precipitable presente en la columna de aire disponible para la poblacion de la ciudad de Copiapo y determinar, ademas, el porcentaje de los elementos detectados en cada muestra. La caracterizacion del material particulado, tanto de los relaves como el capturado en la columna de aire y los recolectores PM10 de alto volumen, fue realizada mediante los analisis PIXE (Proton Induced X-ray Emission) y GIXE (Gamma Induced X-ray Emission). Estos analisis no detectaron la presencia de los elementos mas daninos para la salud humana, a saber, cadmio y arsenico, al menos en puntos cercanos a la ciudad de Copiapo; sin embargo, se logro determinar la presencia de plomo en una zona de alta densidad poblacional.

Production yields of NatZn(p,x)67Ga reaction in the energy range of 1.6 to 2.5 MeV

Production yield of the 67Ga (t? = 78.3hr.)radionuclide was measured by the NatZn(p,x)67 Ga reaction in the energy range from 1.6 to 2.5 MeV. These results are the first reported at energies under 3 MeV. The overall uncertainty of these measurements are around 7%.

Background considerations in the analysis of PIXE spectra by Artificial Neural Systems.

In order to study the importance of background in PIXE spectra to determine elemental concentrations in atmospheric aerosols using artificial neural systems ANS, two independently trained ANS were constructed, one which considered as input the net number of counts in the peak, and another which included the background. In the training and validation phases thirty eight spectra of aerosols collected in Santiago, Chile, were used. In both cases the elemental concentration values were similar. This fact was due to the intrinsic characteristic of ANS operating with normalized values of the net and total number of counts under the peaks, something that was verified in the analysis of 172 spectra obtained from aerosols collected in Mexico city. Therefore, networks operating under the mode which include background can reduce time and cost when dealing with large number of samples.

Ion Beam Facility at the University of Chile; Applications and Basic Research

The main characteristics of the ion beam facility based on a 3.75 MeV Van de Graaff accelerator at the University of Chile are described at this work. Current activities are mainly focused on the application of the Ion Beam Analysis techniques for environmental, archaeological, and material science analysis. For instance, Rutherford Backscattering Spectrometry (RBS) is applied to measure thin gold film thickness which are used to determine their resistivity and other electrical properties. At this laboratory the Proton Induced X‐Ray Emission (PIXE) and Proton Elastic Scattering Analysis (PESA) methodologies are extensively used for trace element analysis of urban aerosols (Santiago, Ciudad de Mexico). A similar study is being carried out at the Antarctica Peninsula. Characterization studies on obsidian and vitreous dacite samples using PIXE has been also perform allowing to match some of these artifacts with geological source sites in Chile.Basic physics research is being carried out by measuring low‐ener...