|
| |
|
| |
|
|
Generation of TiO2 Nanoparticles for Follow-Up Inhalation Experiments with Laboratory Animals
Moravec, Pavel ; Schwarz, Jaroslav ; Vodička, Petr ; Koštejn, Martin
A method of TiO2 nanoparticle generation appropriate for follow-up long lasting inhalation experiments with laboratory animals was tested. Nanoparticles were synthesized in an externally heated tube reactor using titanium tetraisopropoxide as a precursor. Total 264 hours of particle generation in four experimental campaigns was performed with one batch of precursor without observable decrease of precursor volatility. Particle production was studied in wide range of experimental conditions such as reactor temperature, reactor flow rate and precursor vapor pressure by pyrolysis, using nitrogen as a carrier gas, and also in oxidizing atmosphere (10 vol. % of oxygen in the reaction mixture). Particle characteristics were investigated by scanning/transmission electron microscopy, energy dispersive spectroscopy, inductively coupled plasma optical emission spectrometry, elemental and organic carbon analyzer, X-ray diffraction and X-ray photoelectron spectrometry. As a result, particle production with number concentration high above 1.0 x 10(7) #/cm(3) and with primary particle size well below 50 nm can be easily achieved in most of investigated experimental conditions. Particles are free of elemental carbon, content of organic carbon is less than 10 weight %, detected crystalline phase is typically anatase, Ti is present in bonds Ti-O (TiO2) and total Ti concentration recalculated on TiO2 is approximately 80 mass %.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22015041615090 - PDF
|
|
|
Aerosol Chemical Composition Studied by the Aerosol Mass Spectrometry – Identification of Aerosol Emerging during New Year´s Celebration
Kubelová, Lucie ; Vodička, Petr ; Schwarz, Jaroslav ; Ždímal, Vladimír
This study focused on finding of a marker of presence of aerosol originating during fireworks using aerosol mass spectrometer c-ToF-AMS. During the 48-hour campaign, we observed 4 episodes characterized by increased mass concentration of aerosol. Nonetheless, the main focus was placed on the episode right after the New Year's celebration.The AMS spectrometer enabled to identify fragments originating from fireworks. We found that presence of fireworks aerosol particles leads to a significant increase of the ratio m/z 39 and total organic mass. Since the increase in the fragment m/z 39 is usually connected with an increase in organic matter (i.e. with their relatively small mutual ratio), it is possible to consider the increased value of such ratio as a marker of presence of aerosol pariticles originating from firewords.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22015022514110 - PDF
|
|
| |
|
| |
|
|
Characterization of Particulate Matter in Different Archives
Mašková, Ludmila ; Smolík, Jiří ; Vodička, Petr
Indoor air pollution in cultural heritage buildings such as museums, libraries and archives can be harmful for materials stored there. Adverse effects of most of gaseous pollutants are well described (Thomson, 1965), but less is known about airborne particles. Particles cover a wide range of sizes and have a variable composition. These characteristics determine their transport to the surfaces and also possible negative effects (Nazaroff and Cass, 1989).
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22014102013561 - PDF
|
|
|
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
|
|
|
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.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22014102013551 - PDF
|
|
|
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.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22014102013550 - PDF
|
guest ::
RSS feed.