| 1. |
- Akselsson, Roland, et al.
(författare)
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Application of Proton Induced X-Ray Emission Analysis to the St. Louis Regional Air Pollution Study
- 1975
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Ingår i: Advances in X-Ray Analysis. ; 18, s. 588-597
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Tidskriftsartikel (refereegranskat)abstract
- The St Louis aerosol was sampled during the period 16-22 August 1973 simultaneously at two locations using cascade impactors for sequential 12-hour samples. The six particle size fractions of each sampling were individually analyzed using PIXE for elements from S to Br and beyond and for heavy elements including Pb which permitted time variations of concentrations and particle size distributions to be followed and related to meteorological changes during the sampling period. In addition, the data were compared with average levels of the elements in coastal north Florida and maritime Bermuda as well as at a third St. Louis site. From this it appeared that some of the concentrations in St. Louis were at natural levels whereas others appeared to be higher and linked to air pollution sources. These relationships and others in this study may lead to criteria for distinguishing between pollutants and natural background in urban aerosols.
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| 2. |
- Akselsson, Roland, et al.
(författare)
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Particle Size Distribution and Human Respiratory Deposition of Trace Metals in Indoor Work Environments
- 1976
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 1475-3162. ; 19:3-4, s. 225-238
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Tidskriftsartikel (refereegranskat)abstract
- Respiratory response to inhalation of fine particles has been investigated for the aerosol generated by welding. Particles were sampled using a pair of 5-stage cascade impactors operating at 1 l./min flow rate. The subject exhaled into one impactor through an air ballast arrangement, and the other impactor simultaneously sampled the surrounding air. Particle size fractions were analyzed for principal elemental constituents from sulphur to lead using proton induced X-ray emission, PIXE. The results indicated a complex respiratory response, including both increase in particle size due to exposure to high humidity in the respiratory tract and deposition of particles during inhalation. The response was found to be different for the element group Mn, Cr, Fe, Ni compared to the group K, Ca, Ti by observing the associations among the elements as a function of particle size in the inhaled and exhaled aerosol. However, for respiratory deposition efficiency alone in all runs averaged together, no systematic differences between the different elements are demonstrated at the 99 % confidence level.
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| 3. |
- Akselsson, Roland, et al.
(författare)
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Proton Scattering for Analysis of Atmospheric Particulate Matter
- 1975
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Ingår i: Bulletin of the American Physical Society Ser II. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- Proton scattering has been applied to the problem of elemental quantitative analysis of air particulate matter. Elements up through chlorine may be resolved using 16 MeV protons incident upon targets up to about 1 mg/cm2 in thickness. Using the FSU Super FM Tandem Accelerator and a large area solid state proton detector, an analysis can be performed in several minutes. Combination of this technique with proton induced X-ray emission analysis provides a means of quantitative analysis for all elements. These accelerator based methods are being applied to studies of the composition of air particulate matter in diverse locations such as St. Louis, Mo.; Los Angeles, Ca.; several cities in Florida; and Bermuda.
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| 4. |
- Akselsson, Roland, et al.
(författare)
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X-Ray Techniques for Aerosol Sulfur Baseline Assessment Along an Urban Freeway
- 1976
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Ingår i: Advances in X-Ray Analysis. ; 19, s. 415-425
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric aerosol particles have been sampled near a Los Angeles freeway and analyzed by proton-induced X-ray emission, PIXE, as a sulfur baseline study in September 1974 before 1975-model automobiles, equipped with catalytic emission control devices, appeared in large numbers. The sampling plan was optimized according to the requirements of X-ray analysis techniques, fluctuations in air flow across the freeway, and the time and particle size resolution of the aerosol sampling equipment. During five selected two-hour intervals with cross wind conditions, particles were collected as a function of size by six cascade impactors operating simultaneously on three towers at 2 and 7 meters above road level 35 meters upwind and 35 meters downwind of the traffic lanes. Particles as a function of time were sampled continuously, for the 100-hour duration of the experiment, from the tree 7-meter heights using time series streaker filter samplers with two-hour time resolution. Precise analysis of S, Cl, K, Ca, Fe, Br, and Pb established relationships which permit estimates to be made of future increases in particulate sulfur as a consequence of increased sulfate emissions from catalytic automobiles
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| 5. |
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| 6. |
- Desaedeleer, Georges G, et al.
(författare)
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Monitoring Aerosol Elemental Composition in Particle Size Fractions for Predicting Human Respiratory Uptake
- 1977
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 142:1-2, s. 97-99
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Tidskriftsartikel (refereegranskat)abstract
- Proton induced X-ray emission analysis is useful in measuring changes in particle size distribution of trace elements on exposure of aerosol to the human lung environment and deposition in the air-ways. PIXE analysis is also useful in detecting variations in particle size distributions of elements as they occur in the atmosphere. For the case of lead aerosol along a highway, it is shown that the extent and site of respiratory deposition of particles depend on their size, and the size distribution may vary under urban atmospheric conditions sufficiently to affect respiratory deposition efficiency.
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| 7. |
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| 8. |
- Hardy, Kenneth A., et al.
(författare)
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Elemental Constituents of Miami Aerosol as Function of Particle Size
- 1976
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 1520-5851 .- 0013-936X. ; 10:2, s. 176-182
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Tidskriftsartikel (refereegranskat)abstract
- Results are presented of proton-induced x-ray emission analysis of aerosol samples taken in Miami, Fla., in the summer of 1974. Elemental concentrations and elemental ratios as a function of particle size are shown for 13 elements. These size distributions allow the determination of the sources of several elements observed in the Miami aerosol. Data from north Florida and Bermuda are compared.
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| 9. |
- Lannefors, Hans O., et al.
(författare)
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Interelement and Multi-Station Concentration Evidence for Large Scale Aerosol Sulfur Transport across Sweden
- 1980
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Ingår i: Tellus, Series A: Dynamic Meteorology and Oceanography. - : Stockholm University Press. - 0280-6495. ; 32:6, s. 548-557
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Tidskriftsartikel (refereegranskat)abstract
- The concentrations of sulfur and several more elements were measured in a network of six sites in southern Sweden. High time resolution samples were taken using a continuous filter sampler and analysed by particle induced X-ray emission (PIXE). Simultaneous increases in the sulfur concentrations were seen along the network due to the inflow of polluted air masses. High sulfur concentrations generally occurred during south-westerly to easterly air flow. Some of the episodes, distinguished by their shorter duration and their elevated vanadium and nickel concentrations, are suggested to be of local origin.
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| 10. |
- Nelson, J William, et al.
(författare)
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Aerosol Composition Studies Using Accelerator Proton Bombardment
- 1974
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Ingår i: Proceedings of "Third Conference on Application of Small Accelerators". ; 1, s. 139-147
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Konferensbidrag (refereegranskat)abstract
- The proton beam of the Florida State University Tandem Van de Graaff Accelerator is being used to make quantitative determinations of the composition of particulate matter found in the atmosphere. Proton scattering using 16 MeV incident particle energy is employed to resolve the light elements (up to Cl), while elements Al and heavier are observed via proton induced X-ray emission analysis. In order to realize advantages of these proton excited analyses, specialized techniques are used, such as the use of uniform beams which entirely cover the area of targets of non-uniform areal density. Also, specialized air sampling equipment has been built to take advantage of the small size of samples required for proton induced analyses. The multielement character, ease of automation, and short time (several minutes) needed for analysis make these techniques attractive from the standpoint of analysis cost per sample.
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