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A Comparison of Titania Nanoparticles Production in Two Different Reactors by MOCVD Method
Moravec, Pavel ; Smolík, Jiří ; Schwarz, Jaroslav ; Vodička, Petr ; Levdansky, V.V. ; Koštejn, Martin
Nanoparticles (NP's) have attracted considerable attention, because they show a quantum size effect, for which the physical and chemical properties are strongly dependent on particle size. This change of properties can also affect the toxicity and therefore NP's cannot be treated the same way as bulk material. In spite of that, inhalation studies of NP's are still rather rare. Recently, an exposure system for inhalation experiments was constructed in the Institute of Analytical Chemistry AS CR and the first experience with this system were reported by Večeřa et al., 2012. For these studies, a method of continual long-term generation of NP's in the gas phase is necessary. Methods for long-term generation of MnOx and Pb/PbOx NP's have recently been reported. The next task was to test the method for long-term generation of TiO2 NP's suitable for subsequent inhalation experiments.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22014102013554 - PDF
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Search for Links between Organic Aerosols Measured by Aerosol Mass Spectrometer and EC/OC Analyzer
Vodička, Petr ; Kubelová, Lucie ; Makeš, Otakar ; Schwarz, Jaroslav
Carbonaceous aerosols form a major part of particulate matter suspended in the atmosphere. The organic part of aerosol represents a diverse group of substances that can be analyzed in different ways. In this work, the possible linkages between organic fractions measured by Compact Time-of-Flight Aerosol Mass Spectrometer (AMS; from Aerodyne) and a semi-online EC/OC analyzer (from Sunset Laboratories) were search. Each of these instruments provides a different kind of information. Organic fractions from EC/OC analyzer provide knowledges about a diferent volatility of organic carbon (OC) while AMS provide informations about a chemical composition of characteristic mass fragments. Thus, the main objective of this work was to determine whether the organic fractions from EC/OC analyzer can indirectly provide also information on the chemical composition or somehow more characterize type of aerosol.
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Plný tet: SKMBT_C22014102013551 - PDF
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Comparison of Source Apportionment Results from Summer and Winter Measuring Campaign at a Prague-Suchdol Site
Makeš, Otakar ; Vodička, Petr ; Schwarz, Jaroslav
Organic aerosol (OA) is the most abundant but still poorly characterized component of airborne particulate matter. This situation is even more complicated in large cities where many anthropogenic sources of primary organic aerosol (POA) are situated. In recent years, aerosol mass spectrometry has been increasingly applied to obtain highly time-resolved chemical composition of ambient aerosol. This is considerably important for clarification of organic aerosol life cycles and sources. Two measuring campaigns, which lasted about six weeks in summer 2012 and in winter 2013, were performed at suburban site Prague – Suchdol. Aerosol data were measured by Aerodyne compact time-of-flight aerosol mass spectrometer (AMS) which is able to characterize the size resolved chemical composition of non-refractory submicron (PM1) fraction.
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Plný tet: SKMBT_C22014102013550 - PDF
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Identifying of Organic Aerosol Sources by Using of Advanced Factor Analysis
Makeš, Otakar ; Vodička, Petr ; Schwarz, Jaroslav ; Canonaco, F. ; Prevot, A.
Real-time measurement of submicron aerosol was performed at Prague – Suchdol site (Czech Republic) during six weeks in June and July 2012. Organic aerosol data obtained from measurement by C-ToF AMS were deconvoluted using the Multilinear Engine (ME-2) algorithm (Paatero, 1999) and analyzed with the newly developed GUI provided by Paul Scherrer Institute (Canonaco et al. in prep.). During the analysis, we obtained four factor solution which explains more than 95% of the variance. These four factors, related to four aerosol sources, were fixed by the ME-2 model: Hydrocarbon-like organic aerosol (HOA) factor related to the road traffic, biomass burning organic aerosol (BBOA) factor, and two kinds of oxygenated organic aerosol factors (LV-OOA and SV-OOA). LV-OOA factor is the most frequently interpreted as an aged aerosol with low volatility. On the contrary, diurnal patterns of SV-OOA factor exhibit maxima at night and high anti-correlation with temperature. Therefore it can be assumed that SV-OOA factor represents a volatile fraction of OOA.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22013101814580 - PDF
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Synthesis of Lead and Lead Oxide Nanoparticles for Inhalation Experiments
Moravec, Pavel ; Smolík, Jiří ; Ondráček, Jakub ; Vodička, Petr ; Fajgar, Radek
From the three tested methods of NP's generation the evaporation/condensation of metallic Pb seems to be the most suitable for long lasting inhalation experiments due to its simplicity, unambiguous mechanism of NP′s formation and well defined composition. Nevertheless, NP′s can change their composition, at least on the surface layer, during the time-lag between their formation and inhalation. Thermal decomposition of PbTHD2 can produce sufficiently high concentration of NP′s but there is some uncertainty about their composition due to presence of OC in NP′s. Oxidation of PbTHD2 produces carbon free NP′s, but the number concentration of NP′s is somewhat low.
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Plný tet: SKMBT_C22013101814595 - PDF
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Mass Size Distribution of Atmospheric Aerosols and Water Soluble Ions atMlada Boleslav in Winter
Schwarz, Jaroslav ; Zíková, Naděžda ; Vodička, Petr ; Hovorka, J. ; Moravec, Pavel ; Ždímal, Vladimír
The importance of the knowledge of aerosol mass size distribution for understanding aerosol behavior is well known for at least few decades. The water soluble ions represent a driving factor controlling hygroscopicity of aerosol particles that determines how the ambient relative humidity influences aerosol particle size. Therefore, hygroscopicity is a substantial parameter in phenomena like particle deposition in the human respiratory tract, particle – cloud interactions, aerosol optical effects etc. For these reasons, the mass size distribution of atmospheric aerosols and water soluble ions was studied at a Czech medium-size-town Mladá Boleslav in winter.
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Plný tet: SKMBT_C22013101815000 - PDF
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Characterization of Fine Particles by Aerosol Mass Spectrometer at the Prague Suburban Site During Summer and Winter Season
Vodička, Petr ; Makeš, Otakar ; Schwarz, Jaroslav
The increasing interest in the role of aerosols in the atmosphere leads to a growing need to their measurements in the environment. For this reasons, the detailed studies of aerosols were also included into the existing European project ACTRIS (www.actris.net). One of the ACTRIS part is the coordinated long-term measurement of aerosol chemistry both with Aerosol Chemical Speciation Monitors (ACSM) (Ng et al., 2011) and by other types of Aerosol Mass Spectrometers (AMS) (Canagaratna et al., 2007). The measurement network includes many background stations (including urban background sites) all over Europe (http://www.psi.ch/acsm-stations/acsm-and-emep-stations). One of the participating stations was also an urban background site in Prague. This paper presents preliminary results characterizing the fine aerosol at this site during two intensive (summer and winter) measurement campaigns.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22013101814591 - PDF
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