National Repository of Grey Literature 73 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Atmospheric deposition of nitrogen - application of stable isotopes
Hanzlová, Barbora ; Hůnová, Iva (advisor) ; Hovorka, Jan (referee)
Human impact on particular parts of ecosystems has become a highly discussed topic. Due to different isotopic values of nitrogen, it is possible to evaluate the extent to which human influences the natural nitrogen cycle, using isotope measurements. Stable isotope measurement has been used in various scientific disciplines around the world. This thesis summarizes the findings about atmospheric deposition and the subsequent use of stable nitrogen isotopes. The objective of this work was to gather the information about the use of stable isotopes in the study of the atmospheric deposition and how to make better use of the information obtained from the measurements. Based on the literature review, it has been found that, unlike other countries, nitrate substances such as NH3 and HNO3 are not measured in the Czech Republic, which distorts the data on the nitrogen produced. The use of stable isotopes is a convenient method of measuring both not yet quantified substances as well as already measured substances contributing to atmospheric deposition. The stable isotope measurement method represents an improvement for the overall estimation of atmospheric deposition to provide more realistic values compared to the current approach. Key words: atmospheric deposition, nitrogen, stable isotopes
Dynamics of vertical and horizontal profiles of atmospheric aerosol in planetary boundary layer
Esterlová, Jana ; Hovorka, Jan (advisor) ; Jančík, Petr (referee)
The boundary layer of the atmosphere is a layer of air with thickness about 1 km above the ground. Open-cast mining is one of activities that polutes the air in this layer. It generates particulate matter (PM) mostly in size of aerodynamic diameter 1 - 10 µm - coarse patricles. The companies that does the mining pays for their emissions due to the law. However, these emissions are not experimentraly measured, they are calculated from given equation consisting of factors like the size of mining area, etc. Some papers have shown significantly higher concentrations of Coarse particles (or PM10) in surroundings of the mine. Other papers have found out that the origin of these high concentrations didn't come from the mining activities but is caused due to the activities at the place of measuring or nearby. There aren't many papers that measure the PM concentrations in the air in the mining area. This thesis shows the results of airship measurements in the air layers of the open-cast mine and above them. The experimentral site was brown coal mine Bílina in the North of The Czech Republic in important mining area. The measurements took place in December 2017. For measuring the number and mass concentrations was used APS - Aerodynamic Particle Sizes Spektrometr by TSI which sorts out the data into...
Charakterisation of fungal aerosol in size segregated aerosol
Shamratova, Kseniia ; Hovorka, Jan (advisor) ; Kozáková, Jana (referee)
This bachelor thesis deals with the issue of bioaerosol, properties of airborne fungal spores, describes their significance, concentration, methods of spreading and influence on human health. This work provides information about sampling and detection methods of bioaeerosol. Was proved the suitability of using of the first step of the high volume cascade impactor (Hi-Vol) BGI-900 to collect biaerosol samples for subsequent scanning electron microscope (SEM) analysis. Using the optimized method, bioaerosol samples were isolated from the polyurethane foam, which is the impact substrate of the impactor. Bioaerosol samples were taken from 3 locations in the Czech Republic: Prague, Březno, Láz. During the SEM analysis of 15 bioaerosol samples, 605 SEM images were taken, on 340 of them were identified fungal spores. The smallest number of spores were found in Prague. Approximately the same amount of fungal spores was found in Březno and Láz. Fungal spores were identified into 9 genus, 1 family, and 1 species. The percentage of deformed spores in Prague was 48%, in Březno 23%, in Láz 25%. The greatest variability of spores was at the Březno and Láz localities. The most common fungal genus was the Cladosporium genus. No positive or negative correlation was observed between the number of fungi and the...
Spatio-temporal PM2.5 variability in village during winter.
Štědrá, Karolína ; Hovorka, Jan (advisor) ; Bendl, Jan (referee)
This thesis evaluates the spatial variability of PM2.5 concentrations during two winter months in the small village Lbín close to Teplice at the turn of the year 2017/2018. The PM2.5 concentrations were monitored through a dedicated monitoring network using a total of eight DustTrak laser nephelometers (Model 8520). Six DustTraks were located directly in the village in the valley, one of them was located on the hill above the valley and the last one was located approximately in the half of the hill. Using a network measurements, we tried to determine that the household heatings are the main sources of air pollution in the village. The basic meteorological parameters - wind speed and direction, temperature and air humidity were monitored together with PM2.5 concentrations. It was observed statistically significant difference between the measuring stations, which points to the unevenly distribution of pollution sources. The particle concentrations typically reach peak values in the morning and in the evening. The maximum peak values were 2607 μg·m-3 in December and 4347 μg·m-3 in January. The lowest maximum values were 223 μg·m-3 and 177 μg·m-3 for devices located above the village. An important factor contributing to the current situation was wind speed. If the wind speed was higher than 1,29 m·s-1...
Atmospheric deposition of nitrogen - application of stable isotopes
Hanzlová, Barbora ; Hůnová, Iva (advisor) ; Hovorka, Jan (referee)
Based on the literature review, the thesis summarizes the use of stable isotopes in the atmospheric deposition. According to the studies and empirical research, the origin and the extent of the pollution in the environment can be tracked down. Due to the different isotopic values, it is possible to evaluate the extent of human impact on the natural cycle of the ecosystem. Nitrogen can be found in all nature constituents where it gains different isotopic values. The objective of this work was to gather the information about the stable isotopes and to prove whether they are reliable indicators in determining the source of the nitrogen in the given area. By using the evaluated study, the difference in pollution within the coastal and continental areas in Central Europe was described. Keywords: atmospheric deposition, nitrogen cycle, stable nitrogen isotopes, fractionation
Atmospheric aerosol: physical-chemical characterisation and source apportionment
Leoni, Cecilia ; Hovorka, Jan (advisor) ; Ždímal, Vladimír (referee) ; Lammel, Gerhard (referee)
Atmospheric aerosol is a ubiquitous component of the Earth atmosphere. By mass, aerosol natural sources override anthropogenic ones, the latter constituting less than 5% to the total aerosol loading (Jaenicke, 2008). Nevertheless, in urban environment the contribution can increase to 80-90%. Since anthropogenic sources are mostly associated with high temperature processes, urban aerosol number size distribution is usually dominated by ultrafine particles - UFPs (d<100 nm). The UFPs have the highest surface/mass ratios among aerosol particles and bond the highest pollutant loading as per particle mass. Additionally, the UFPs exhibit the highest deposition efficiency in deep region of the human respiratory tract. Therefore, this study focuses to urban aerosol particle spatial-temporal, physical and chemical characterization and source apportionment with special emphasis to the UFPs. The first study in residential district of Ostrava-Radvanice and Bartovice, an air pollution hot spot in Europe, identified industry being dominant sources of UFPs. High particle number concentrations (NC) were measured at the hot spot, with peaks up to 1.4x105 particles cm-3 during plume events, i.e. downwind an industrial facility. The plume-originating UFPs were mostly composed of 19−44 nm nanoparticles heavily...
Study of aerosol properties with high time resolution
Kubelová, Lucie ; Ždímal, Vladimír (advisor) ; Hovorka, Jan (referee) ; Vojtíšek, Michal (referee)
This thesis focuses on physical and chemical characteristics of atmospheric aerosol measured with high time resolution. Size distribution, chemical composition, and volatility of submicron particles were studied in relation to meteorological conditions and other factors. To reach higher variability in ambient conditions, we considered atmospheric aerosol during two seasons of the year (summer and winter) and at two different locations (suburban site Prague Suchdol and rural site Košetice). Measurement during two different seasons enabled us to better distinguish the influence of seasonal sources such as domestic heating in winter and increased biogenic emissions in summer. Also, seasonal differences in meteorological conditions mainly in case of temperature, humidity, and solar radiation were shown to play a role in aerosol characteristics. A comparison of aerosol properties at two different measurement sites, namely a rural and suburban, enabled us to better characterize the role of background aerosol and the influence of the city. Furthermore, a transformation of aerosol particles entering indoors from outdoors was also studied within this thesis. The influence of indoor/outdoor temperature and humidity gradient as well as presence of new particle formation events on the indoor/outdoor ratio was...

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