Chemically-assigned classification of aerosol mass spectra.

An Algorithm for Discriminant Analysis of Mass Spectra--ADAMS--was created that classified aerosol mass spectra into dominant chemically-assigned classes, and grouped rare cases in an outlier class. ADAMS was trained with ambient particulate matter (PM) mass spectra, and then validated through classification tests on known spectra with random noise added, various standard chemicals, and salt-spiked polystyrene latex microspheres. The classification results showed that ADAMS gave a reasonable chemical description of the particle populations. In contrast to adaptive resonance theory (ART-2a) classification, ADAMS could be trained to be advantageously sensitive or insensitive to selected chemical markers. Application of ADAMS to Toronto ambient PM and diesel PM (NIST 2975) demonstrated that these samples could be well described, with a low proportion of the cases falling into the outlier class. Such an algorithm may find application for source-receptor modeling of aerosol mass spectra.

[Radioactivity for 137Cs, 125I, 131I, 59Fe, y 57Co windows from foods included in the basic alimentary basket and in the water, consumed in the state of Carabobo, Venezuela]. / Radioactividad en las ventanas de 137Cs, 125I, 131I, 59Fe, y 57Co de alimentos incluidos en la cesta básica y en el agua, consumidos en el estado Carabobo, Venezuela.

One of the input ways of radionucleids into the organism is through food intake. The aim of the present study is to measure the radioactivity levels in food and water samples within energy windows corresponding to 137Cs, 125I, 131I, 59Fe, and 57Co. Samples were taken from local and imported food belonging to the venezuelan basic alimentary basket and included: beef meat, hen egg, chicken bone, tomato, black bean, rice, powder milk from local dealers or imported from Italy and New Zeeland, potable water from the Valencia city aqueduct and bottled water from local sources or imported from Portugal. Radioactivity was measured with a well type Nal (TI) scintillation counter. Analyzed foods and water presented levels lower than the minimal detectable activity for 137Cs, 131I, 59Fe, 57Co, but it was detected in the Valencia city aqueduct water and in bottled water imported from Portugal, levels greater than the minimal detectable activity for the 125I energy window. These results strongly suggest the need of repeated multienergy windows monitoring of radioactivity of basic alimentary basket foods and potable water.

On-line analysis of urban particulate matter focusing on elevated wintertime aerosol concentrations.

A 10-day winter sampling campaign was conducted in downtown Toronto for particulate matter (PM) air pollution in the fine (<2.5 microm) size range. An aerosol laser ablation mass spectrometer (LAMS), a tapered-element oscillating microbalance (TEOM), and an aerodynamic particle sizer (APS) were operated in parallel to characterize the PM on-line. In this study, the LAMS observed differences in the chemical composition between three separate episodes with higher PM2.5 mass and APS counts. LAMS results showed that in one instance of elevated PM, organic amines were present in the particulates. Temporal analyses of this episode revealed chemical transformations as the amines, characterized by m/z peaks 58(C3HeN)+, 86(C5H2N)+, and nitrates, increased in number concentration while Ca and hydrocarbon particle classes concurrently decreased. On another day, sulfates were found to have increased significantly. The third event was only 4 h in duration and exhibited an increase in the number of submicron-sized K/hydrocarbons and sulfate-containing particles. In this last event, the hydrocarbons and a K to Fe ratio enrichment indicated there was likely a contribution from a combustion source. This work offers some of the first insights into single particle size and chemistry in a cold winter climate.

Radioactividad en las ventanas de 137 Cs, 125 I, 131 I, 59 Fe, y 57 Co de alimentos incluidos en la cesta básica y en el agua, consumidos en el Estado Carabobo, Venezuela / Radioactivity for 137 Cs, 125 I, 131 I, 59 Fe, y 57 Co windows from foods inclued in the basic alimentary basket and in the water, consumed in the state of Carabobo, Venezuela

Uno de los medios de ingreso de Radionucleidos Artificiales y Naturales al organismo es la alimentación. En el presente estudio se determinaron los niveles de radioactividad de las ventanas de energía correspondientes a 137 Cs, 125 I, 131 I, 59 Fe, y 57 Co en alimentos y bebidas tanto nacionales como importados, pertenecientes a la cesta alimentaria básica venezolana: alimentos de origen animal como carne vacuna, huevo de gallina y hueso de pollo; alimentos de origen vegetal como tomate, papa, caraota negra y arroz; agua embotellada nacional e importada de Portugal y agua del acueducto; y leche en polvo completa nacional, de Italia y de Nueva Zelanda. La radioactividad fue medida con un contador de centelleo de pozo con cristal NaI(Tl). Se concluye que los alimentos y bebidas examinados, presentan niveles menores a la actividad mínima detectable para 137 Cs, 131 I, 59 Fe, 57 Co, mientras que para el radionucleido 125 I se detectaron, en el agua de acueducto de la ciudad de Valencia y el agua embotellada importada de Portugal, niveles por encima de los mínimos detectables. Estos datos sugieren fuertemente la necesidad de monitorizar constantemente los niveles de radioactividad en varias ventanas energéticas de los alimentos de la cesta básica alimentaria y del agua potable.

Mapas BI y tridimensionales de isodosis de radiación ambiental gamma en el Municipio Naguanagua Valencia Venezuela: período septiembre 1999- agosto 2000 / Environmental gamma radiation levels analyzed by bi-and tridimensional isodosis maps in a polygonal urban zone of the municipal district of Naguanagua Valencia Venezuela: from september 1999 to august 2000

La presente investigación cuantificó los niveles de radiación ambiental gamma (RAG) en una zona poligonal urbana del Municipio Naguanagua, Valencia, Venezuela en el período septiembre 1999 - agosto de 2000 correlacionándolos con la altura, humedad y temperatura ambiental. La media de RAG para el lapso registrado fue de 7, 53 ± 1,89 CPM y la exposición menor de 0,2 mR.hora-¹. El mapa general de isodosis de RAG mostró un área central con valores de CPM intermedios, las áreas este y oeste con elevación de dichos niveles, y una disminución en las áreas norte y sur. La altura, humedad y temperatura ambiental de la zona no se correlacionaron con los niveles de RAG (p>0,05)