| 1. |
- Akselsson, Roland, et al.
(author)
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Particle Size Distribution and Human Respiratory Deposition of Trace Metals in Indoor Work Environments
- 1976
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In: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 1475-3162. ; 19:3-4, s. 225-238
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Journal article (peer-reviewed)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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| 2. |
- Akselsson, Roland, et al.
(author)
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X-Ray Techniques for Aerosol Sulfur Baseline Assessment Along an Urban Freeway
- 1976
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In: Advances in X-Ray Analysis. ; 19, s. 415-425
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Journal article (peer-reviewed)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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| 3. |
- Hardy, Kenneth A., et al.
(author)
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Elemental Constituents of Miami Aerosol as Function of Particle Size
- 1976
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In: Environmental Science & Technology. - : American Chemical Society (ACS). - 1520-5851 .- 0013-936X. ; 10:2, s. 176-182
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Journal article (peer-reviewed)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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| 4. |
- Nelson, J William, et al.
(author)
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Automatic Time Sequence Filter Sampling of Aerosols for Rapid Multi-Element Analysis by Proton-Induced X-Ray Emission
- 1976
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In: Advances in X-Ray Analysis. ; 19, s. 403-413
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Journal article (peer-reviewed)abstract
- An automatic time sequence filter sampler has been developed for atmospheric aerosol particle sampling of ambient air and subsequent analysis for elemental composition using the proton beam of a Van de Graaff accelerator. Some features of the operation of the sampler are given, the retention of particles by the filter material are discussed, examples of the type of data obtained are presented, and some approaches to the numerical analysis of data for environmental interpretation are considered. Lines for further development and improvement in this type of sampler are indicated.
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| 5. |
- Sheline, Jonathan, et al.
(author)
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Trace Element Similarity Groups in North Florida Spanish Moss
- 1976
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In: Journal of Geophysical Research. - 2156-2202. ; 81:6, s. 1047-1050
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Journal article (peer-reviewed)abstract
- The elemental composition of 10 samples of Spanish moss Tillandsia usneoides L. collected mainly in forested areas near Tallahassee, Florida, has been compared to the composition of the ambient aerosol particle background in the forest measured as a function of particle size. For forest samples, moss composition is similar to the composition of aerosol particles greater than about 0.5-μm diameter for the elements S, Cl, Ti, V, Fe, Ni, Zn, Br, Pb, and possibly Cu. Elements relatively enriched in the moss fall into two groups, K, Rb, Zr and Ca, Sr, Mn, based on detailed association patterns. No evidence is found for an enrichment, relative to the ambient aerosol, of pollution-derived elements Pb, Br, V, and Ni, although those elements are found at higher concentrations in moss samples from locations nearer roadways or oil-fired power plants. The moss appears to have potential value as an indicator of time average aerosol composition for particles of ≥0.5 μm, except for the enriched elements, which may have longer biological retention times.
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| 6. |
- Van Grieken, René E., et al.
(author)
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Geophysical Applicability of Aerosol Size Distribution Measurements Using Cascade Impactors and Proton Induced X-Ray Emission
- 1976
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 0004-6981. ; 10:8, s. 571-576
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Journal article (peer-reviewed)abstract
- Proton Induced X-ray Emission, (PIXE), is capable of high precision analysis for trace element components of aerosol particle size fractions sampled by cascade impactor. A statistical evaluation of data quality has been carried out in order to distinguish between analytical uncertainties in the PIXE procedure, errors caused by cascade impactor performance and by other factors in the sampling procedure, and geophysical causes of differences in composition and particle size distributions of the elements in aerosols. Replicate analyses and simultaneous samplings taken in north Florida and St. Louis have been used for the data evaluation. In addition to the analytical error the sampling procedure contributes an error of ~ 10% to be added quadratically. The resulting precision is sufficient to evaluate the data in geophysical terms. This is illustrated by means of sample sets taken simultaneously in an urban, forest and coastal environment of the same region.
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