| 311. |
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| 312. |
- Swietlicki, Erik, et al.
(författare)
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PIXE Detection Limits for some Aerosol Collection Substrates by Excitation with protons and 4He2+ Ions from a 3 MV Tandem Accelerator
- 1984
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - 0168-583X. ; :1084, s. 441-445
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Tidskriftsartikel (refereegranskat)abstract
- Comparisons of PIXE detection limits for K, X rays using 2-5 MeV protons and 7-8 MeV 4He2+ ions as projectiles have been performed. The comparisons have been made for common aerosol backings. According to simple theoretical considerations regarding X-ray production cross sections and the production of background radiation, detection limits for 4He2+ should be two to four times lower than for protons for equal vefoeity projectiles of equal numbers. However, the background in X-ray spectra arising from gamma-quanta being Compton scattered in the Si(Li) detector can strongIy affect the detection limits. The detection limits using protons and 4HeZ+ ions from a 3 MV electrostatic tandem accelerator are determined and discussed.
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| 313. |
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| 314. |
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| 315. |
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| 316. |
- Wierzbicka, Aneta, et al.
(författare)
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Detailed diesel exhaust characteristics including particle surface area and lung deposited dose for better understanding of health effects in human chamber exposure studies
- 2014
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 86, s. 212-219
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Tidskriftsartikel (refereegranskat)abstract
- Several diesel exhaust (DE) characteristics, comprising both particle and gas phase, recognized as important when linking with health effects, are not reported in human chamber exposure studies. In order to understand effects of DE on humans there is a need for better characterization of DE when performing exposure studies. The aim of this study was to determine and quantify detailed DE characteristics during human chamber exposure. Additionally to compare to reported DE properties in conducted human exposures. A wide battery of particle and gas phase measurement techniques have been used to provide detailed DE characteristics including the DE particles (DEP) surface area, fraction and dose deposited in the lungs, chemical composition of both particle and gas phase such as NO, NO2, CO, CO2, volatile organic compounds (including aldehydes, benzene, toluene) and polycyclic aromatic hydrocarbons (PAHs). Eyes, nose and throat irritation effects were determined. Exposure conditions with PM1 (<1 mu m) mass concentration 280 mu g m(-3), number concentration 4 x 10(5) cm(-3) and elemental to total carbon fraction of 82% were generated from a diesel vehicle at idling. When estimating the lung deposited dose it was found that using the size dependent effective density (in contrast to assuming unity density) reduced the estimated respiratory dose by 132% by mass. Accounting for agglomerated structure of DEP prevented underestimation of lung deposited dose by surface area by 37% in comparison to assuming spherical particles. Comparison of DE characteristics reported in conducted chamber exposures showed that DE properties vary to a great extent under the same DEP mass concentration and engine load. This highlights the need for detailed and standardized approach for measuring and reporting of DE properties. Eyes irritation effects, most probably caused by aldehydes in the gas phase, as well as nose irritation were observed at exposure levels below current occupational exposure limit values given for exhaust fumes. Reporting detailed DE characteristics that include DEP properties (such as mass and number concentration, size resolved information, surface area, chemical composition, lung deposited dose by number, mass and surface) and detailed gas phase including components known for their carcinogenic and irritation effect (e.g. aldehydes, benzene, PAHs) can help in determination of key parameters responsible for observed health effects and comparison of chamber exposure studies. (C) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.
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| 317. |
- Wierzbicka, Aneta, et al.
(författare)
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Experimental Studies on Particle Emissions from Grate Fired Biomass Combustion Boilers
- 2002
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Ingår i: ; , s. 1054-1056
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Konferensbidrag (refereegranskat)abstract
- Fine particle emissions were measured at two commercial grate fired boilers operating on moist fuel residues. The aim of this study was to characterize fine particle emissions with a view to pinpoint parameters influencing the emissions. Additionally effectiveness of used flue gas cleaning techniques was assessed. The results show that large quantities of fine particles are emitted to the atmosphere from both boilers. From 1 MW boiler equipped only in multicyclone 4.8*107 of particles/cm3 (particles with diameter smaller than 0.6 μm) are emitted to the atmosphere. From 6 MW boiler equipped in multicyclone, ESP and flue gas condenser 1.7*106 of particles/cm3 (< 0.6 μm) end up in the atmosphere. Significant fluctuations in the coarse mode (1-10 μm) number concentration over time were observed in 1 MW boiler (between 100 and 10000 particles/cm3) and these were much higher than in 6 MW boiler (between 6000 and 11000 particles/cm3). Operating load showed to have a significant influence on coarse particles number concentration. Collection efficiency of ESP was assessed for about 96% by number and 83% by mass. Number concentration of particles passing through the flue gas condenser was close to unaltered, while mass concentration was reduced by half.
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| 318. |
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| 319. |
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| 320. |
- Wierzbicka, Aneta, et al.
(författare)
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Fine Particles in a Residential Apartment
- 2012
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Ingår i: Proceedings of the "Workplace and Indoor Aerosols Conference" (electronic version only). ; , s. 55-55
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Konferensbidrag (refereegranskat)
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