National Repository of Grey Literature 58 records found  beginprevious48 - 57next  jump to record: Search took 0.00 seconds. 
Comparability of Methods to Measure Black and Elemental Carbon in Two European Urban Areas - Site and Seasonal Similarities and Differences
Hitzenberger, R. ; Schwarz, Jaroslav ; Aschauer, I. ; Haindl, R. ; Ludwig, W. ; Wagner, R. ; Wonaschuetz, A. ; Zecha, G. ; Ševčíková, Irena ; Vodička, Petr ; Zíková, Naděžda ; Ždímal, Vladimír
The goal of the current study is to investigate whether similar conversion factors are applicable at the sites and whether the conversion factors obtained earlier (i.e. ca. 10 years ago) for Vienna are still valid or whether changing source conditions have resulted in shifts of the carbonaceous fractions of the aerosol that would require a new set of conversion factors.
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Comparison of Mass Size Distribution of PM and Ions in Prague and Vienna in Winter and Summer
Schwarz, Jaroslav ; Zíková, Naděžda ; Vodička, Petr ; Ševčíková, Irena ; Kugler, Josef ; Wonaschuetz, A. ; Aschauer, I. ; Ludwig, W. ; Haindl, R. ; Zecha, G. ; Hitzenberger, R. ; Ždímal, Vladimír
The results we obtained on mass size distributions of mass and water soluble ions exhibit common basic features of ambient aerosols in Central Europe. E.g., mass size distributions in winter were dominated by a fine mode. Sulfates and ammonium were almost exclusively present in the fine mode, fine nitrates were mostly low in summer due to high summer temperatures, but they had always a distinct coarse mode. Normal size distributions of ammonium and sulfates were often almost identical in summer due to low nitrates.
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Diffusion Battery – The Renewed Aerosol Spectrometer for Nanoparticles
Holubová Šmejkalová, A. ; Ondráček, Jakub ; Zíková, Naděžda ; Ždímal, Vladimír
The aim of the experiments was to develop new control software for the diffusion battery model DB 3040, in order to optimize measurements with this device. The software allows for larger variability of key control parameters of the diffusion battery and re-opens its application beyond determination of activity size distributions. In comparison with the most widely used method of aerosol spectrometry based on electrical mobility of particles, the method of diffusion battery can be advantageous in situations where we need to measure aerosols of relatively low concentrations with size distributions peaking bellow 20 nanometers.
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Penetration of Commercial Filter Materials in Detailed Study
Ondráček, Jakub ; Zíková, Naděžda ; Ždímal, Vladimír
Testing of various filter materials proved the functionality, good precision and reproducibility of a home-made filter tester. The measurements of penetration for standard commercial filter materials might be useful for many scientists and other users working with these materials. The comparison of penetration for different types of filtration materials showed wide variety of penetration curves, MPPS and the maximum penetration. This study also confirmed our initial doubts about the standard filter efficiency testing method, regarding the used testing material, setting of MPPS and measuring only the total penetration of a polydisperse aerosol. Therefore, such a study could serve also as a basis for improvements in the filter efficiency standard method, which seems to give insufficient and in some perspectives limited or even misleading information.
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Mass Size Distribution of Water Soluble Ions in Prague and Wiena in Summer
Schwarz, Jaroslav ; Vodička, Petr ; Zíková, Naděžda ; Hitzenberger, R.
Aerosol mass size distribution is a key factor that influences aerosol behavior both on local (health effects, visibility) and global (global warming) level. The content of water soluble ions is the most important factor controlling hygroscopic behavior of aerosol particles. Hygroscopicity is a substantial parameter for particle deposition in lungs, particle – cloud interactions, aerosol optical effects etc. Therefore we studied size distribution of water soluble ions in two Central European capitals – Prague and Vienna. In this work, the results from summer campaigns are presented.
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Statistical Evaluation of New Particles Formation Events at Košetice Station
Zíková, Naděžda ; Ždímal, Vladimír
In this work, we present a basic statistical evaluation of NPF at Košetice background station in the region of middle Europe.Variability between the two years is not high, especially ratio of NPF events to all classifiable days varies only by several percents between the two years. Results from Košetice station are very similar to those from Hyytiala station (Finland), despite different geographical location and different time periods.
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SMPS Spectra during Various Meteorological Conditions
Zíková, Naděžda ; Ždímal, Vladimír
This work describes first results of categorization of aerosol PSD according to the various meteorological conditions connected to atmospheric humidity.
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Deposition of Aerosol Particles on Filter Surfaces
Smolík, Jiří ; Mašková, Ludmila ; Zíková, Naděžda ; Ondráček, Jakub
The simple model showed that the particle penetration and deposition depend on particle size and width of the gap, with the depth of the penetration limited by parallel diffusional deposition on filter surfaces. Smaller particles penetrate faster and deeper resulting in higher particle number concentration of deposited particles but higher mass is transported by larger particles. The results of modelling have been qualitatively confirmed by Ion Chromatography using sulphate as marker for deposited particles.
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Filtration Efficiency Measurements of a Filtering Facepiece Material as a Function of Particle Size
Ždímal, Vladimír ; Rupová, M. ; Kovářová, E. ; Zíková, Naděžda
A detailed size-dependent filtration efficiency measurements of a filtering facepiece material have been performed in this work over the range of particle mobility diameters 20-450 nm. It was not the aim of this work to repeat the standard test of the filtration halfmask according to ČSN EN 149+A1. Instead, we have focused on elaborating a procedure enabling us to assess how well the facepiece is suited for usage in working environments with elevated concentrations of aerosol nanoparticles.

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