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PM2.5 mass was measured daily with three batch samplers, a PM2.5 R&P Partisol-Plus FRM, an Andersen RAAS, and a BYU PC-BOSS, and continuously with a TEOM monitor during July and August 2000. PM2.5 composition was also determined. These data are part of an ongoing PM2.5 characterization program centered around a sampling site at the National Energy Technology Laboratory Pittsburgh campus. The composition and concentrations of PM2.5 were both highly variable during this time period. Likely sources of PM2.5 during low concentration periods were transportation, coal-fired boiler, and other emissions generated in the local area. For these periods, the average concentration of PM2.5 was 13 μg/m3 and 70% of the PM2.5 mass was carbonaceous material, including semivolatile organic material that was lost in varying degrees from both the TEOM and FRM samplers. In contrast, much higher concentrations of PM2.5 were associated with transport of pollutants to the site. Analysis of meteorological and back-trajectory data...

The concentration and composition of PM2.5 has been measured with a variety of continuous and integrated samplers at the Hawthorne EPA Environmental Monitoring for Public Awareness and Community Tracking (EMPACT) sampling site in Salt Lake City, UT, and at an EPA Science to Achieve Results (STAR) sampling site in Bountiful, UT. Data are considered at both sites during a 10-day winter period with high PM2.5 concentrations due to winter inversions, and at the Hawthorne site only during a fourteen day summer period when the site was impacted by smoke from wildfires in the Wasatch Mountains. The PM2.5 was dominated by organic material and ammonium nitrate in the winter and by organic material in the summer. In both cases, substantial amounts of sem-volatile material, SVM, was present which was not measured by a Tapered Element Oscillating Microbalance (TEOM) monitor but was detected by a Real-Time Ambient Mass Sampler (RAMS). The PM2.5 data have been combined with concentrations of particulate soot and soil c...

Etude de la conversion SO 2 en sulfate dans le panache d'une centrale electrique chauffee au petrole situee pres de la cote Pacifique

Proton particle-induced x-ray emission (proton PIXE) analysis has been used for the determination of minor and trace element concentrations in obsidian artifacts. Thin targets were made from the acid digests of 30 to 100 mg of finely powdered obsidian samples. Concentrations are reported for K, Ca, Tl, Ba, Mn, Fe, Zn, Ga, Rb, Sr, and Zr. Forty-nine obsidian artifacts from Northern Campeche, Mexico, were analyzed. Methods used for the association of obsidian artifacts with geological sources are illustrated.

Negative errors as large as 50% may occur in particle induced x-ray emission (PIXE) determinations of sulfur concentration in environmental samples. The low values obtained by PIXE in this study are due to chemical reactions induced by irradiation and to loss of sulfur species which are volatile at the temperatures produced by the particle beam under some conditions. The use of small beam currents can eliminate the losses due to simple heating but not those due to radiation-induced reactions. 4 tables.

Proton particle-induced X-ray emission (PIXE) analysis has been used to determine the concentrations of K, Ca, Ti, Mn, Fe, Co, Ni, Cu, Zn, Se, Br, Rb, Sr, Cd, Cs, and Pb in liver, spleen, aorta, kidney medulla, kidney cortex, abdominal fat, pancreas, and hair taken at autopsy from Southwest Indians, primarily of the Pima tribe. Samples were prepared by a low-temperature ashing procedure which is compared to other preparation methods. Data were analyzed by a computer program, ANALEX. The accuracy is tested with NBS standard reference materials and with flame atomic absorption spectrophotometric results. The precision allowed observation of element concentration differences between replicate, half-gram samples of the same tissue. The differences appeared to arise from tissue inhomogeneities. 5 figures, 4 tables.

Fly ash samples were collected from the flue lines of two different oil-fired power plants and analyzed by a variety of analytical procedures designed to determine the V cations extractable from the samples. Both VO/sub 2//sup +/ and VO/sup 2 +/ were shown to be present in the samples. The V(V) cation, VO/sub 2//sup +/, was the principal species extracted from these samples.