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Surface ozone influence on native vegetation: results based on ozone visible symptoms and stomatal flux
Matoušková, Leona ; Hůnová, Iva (advisor) ; Albrechtová, Jana (referee) ; Hovorka, Jan (referee)
Regarding the vegetation, the most affected areas by high levels of surface ozone (O3) are the mountain ridges. Our study has been carried out in the Jizerske hory Mts. High O3 levels together with the convenient environmental conditions for stomatal conductance could be a threat for the health of recovering ecosystems in this area. The aims of this study was both to assess the influence of O3 on vegetation in the Czech mountains and to provide recommendations and outlooks for possible future using of relatively new methods (visible symptoms and stomatal O3 flux modelling) used for O3 impact assessment on native vegetation in the field; that means physiologically relevant methods for the determination of O3 influence. During 2006 and 2007, O3-like visible symptoms were assessed on the leaves of seven species at four sites. Symptoms on only two species (Fagus sylvatica L. and Rubus idaeus L.) have been determined as O3-induced. To our knowledge, it is the first study in the Czech Republic in which the O3-like symptoms on native plants have been verified by the Ozone Validation Centre for Central Europe. Our results based on O3-induced symptoms indicate that ambient O3 is likely to have a much lower impact than expected, considering the measured O3 concentrations (measured with passive samplers) and...
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Temperature and relative humidity vertical profile in atmosheric boudary layer by drone
Fedorenko, Mykhailo ; Hovorka, Jan (advisor) ; Bendl, Jan (referee)
The lower 200 meters of the atmospheric boundary layer (ABL) is characterized by a high amount of atmospheric pollutants, whose distribution and transport can be predicted based on vertical profiles of specific physical parameters. Therefore, acquiring detailed vertical profiles in this range is essential. Traditional methods of measuring vertical profiles are not fully applicable in the context of the SL range. Radiosondes are not designed for frequent measurement of vertical profiles within 200 meters, and remote sensing methods often lack the spatiotemporal resolution needed for detailed measurements of such profiles, can monitor only certain parameters, have specific operational characteristics, and are associated with high costs. In contrast to these methods, the use of a drone as a mobile platform offers advantages in the form of high spatiotemporal resolution and the ability to profile at short intervals, which enables the capture of detailed dynamics of vertical profiles within 200 meters. In this work, using the DJI Air 2s drone equipped with an iMet-XQ2 sensor, measurements of temperature (T) and relative humidity (RH) vertical profiles were conducted. The drone's vertical ascent speed was approximately 1 m/s, so measuring a profile up to 120 meters typically took about 120 seconds, with...
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Distribution of aerosol particles from ship diesel engines
Šmok, Dominik ; Hovorka, Jan (advisor) ; Vojtíšek, Michal (referee)
3 Abstract Measurements of aerosol particle size distributions in the range 5 nm - 4 µm at 1.5 m above sea level were carried out on board a boat in German waters of the Baltic Sea. The measurements were aimed at characterizing aerosol particles from marine aerosol and from ship diesel engines and their dynamics, i.e. the aging of the exhaust plume in the marine boundary layer. The marine aerosol of PNC5-340 1335-1939 cm-3 is characterized by Aitken, accumulation and coarse modes of CMD 20 and 41-55 nm and 123-159 nm and 1.6 µm, respectively. The ratio of the accumulation to the Aitken mode increases with increasing shipping density. Aerosol particles from diesel engines in exhaust plumes with an age of 2 - 60 s and at a distance of 150 - 600 m from the surveyed ships are characterized by PNC5-340 1-4 -105 cm-3 and CMD 20 nm. The modal size distribution of supermicron particles of Da 1 - 4 µm does not change in the exhaust plume, the total mass of supermicron particles increases only by 1 - 6% compared to the background. The dynamics of the size distributions of aerosol particle numbers is mainly due to the formation, i.e. expansion and dilution, of the plume. However, in the exhaust plume with an age of 6 - 16 s and at a distance of 50 - 150 m, a faster decrease was observed for PNC20 due to the...
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Prediction on Capital Market by Fundamental Analysis
Hovorka, Jan ; Prokopec, Michal (referee) ; Sojka, Zdeněk (advisor)
The master’s thesis is focused on prediction on capital market by fundamental analysis. It's principle and methods that can be used for intrinsic stock value evaluation are described in the theoretical part. The experimental part goes in for the fundamental analysis of the company ČEZ. Evaluated intrinsic value of the stock is compared with the current price of a stock on the Czech stock exchange and the investment strategy is discussed.
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Spatio-temporal distribution of atmospheric aerosol in urban and rural environment
Bendl, Jan ; Hovorka, Jan (advisor) ; Mikuška, Pavel (referee) ; Vojtíšek, Michal (referee)
Air quality in Europe remains a significant environmental concern, affecting the health and quality of life of its population. While stationary network ambient air quality monitoring allows for the observation of main trends, it is not fully representative of personal exposure of citizens due to high spatio-temporal variability of atmospheric aerosol. Therefore, highly time-and- space resolved measurements with state-of-the-art instruments and methods are needed to observe the aerosol variability, dynamics, identify hot-spots, and pollution sources, which are necessary for successful targeted mitigation measures. This thesis addresses this gap focusing on the characterization of spatio-temporal distribution of atmospheric aerosol in inhabited environments. Novel mobile measurement systems were developed and employed to investigate diverse environments, including rural, urban and suburban area. Aerosol source-apportionment were conducted, and the toxicological effects associated with these environments were also investigated. A novel mobile measurement system was developed for personal exposure measurements and pollution mapping in urban and rural environments. The system was used to measure air quality in the Munich subway, revealing high aerosol dynamics with significantly higher concentrations of...
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Clarinet in the production of the Czech classicist composers".
HOVORKA, Jan
This diploma paper is focused on clarinet music written by Czech composers of the classicist period, including anonymous compositions, which were preserved on the Czech territory. It pays attention both to solo concertos, as well as the chamber music. It is concerned also with the historical development of clarinet and its most important moments. The aim of this thesis is to provide some less known information about various compositions in a comprehensible way.
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PM2.5 concentration field in the air of Zadni Treban village during heating season
Wallenfelsová, Karolína ; Hovorka, Jan (advisor) ; Mareš, Petr (referee)
This bachelor thesis evaluates the impact of local heating on PM2,5 concentrations mo- nitored in a village Zadní Třebaň in Central Bohemia between 21. 12. 2021 and 3. 2. 2022. It also examines the effect wind speed and temperature have on the PM2,5 concentrations. The PM2,5 concentrations were measured using both stationary and mobile monitoring. For the stationary monitoring, 7 DustTrak 8520 monitors (integration time 1 min) were used. A network of these monitors was built to cover different settlement (village edge, village center) as well as geological types of locations (valley, hill). The mobile monitoring took place 31. 1. 2022 over the course of 7 walks during which PM2,5 and PNC concentration were measured. Portable monitors were used for mobile mea- surements - DustTrak DRX for measuring PM2,5 concentrations and P-Trak for measuring particle number concentrations (PNC). The integration time for both of these monitors was 1 s. The aim of the mobile monitoring was to supplement knowledge gained from the stationary monitoring. The highest average 24h PM2,5 concentrations were measured on the 22. and 23. 12. 2021. On the 22nd the US EPA limit of 35 µg · m−3 was exceeded on almost all measuring sites except Stations 4 and 7. On the 23rd the limit was exceeded on all measuring sites except...
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PM2.5 field in the air of Družec village during heating season
Šmok, Dominik ; Hovorka, Jan (advisor) ; Kozáková, Jana (referee)
Residential heating by solid fuel combustion in small settlements has great potential to degrade air quality, especially PM2.5 emissions, during the winter heating season, to such an extent, that WHO and US-EPA limits for PM2.5 are frequently exceeded. There were found significant temporal variability and spatial heterogeneity of the PM2.5 concentration field. 24h limit for PM2.5 (US-EPA, 35 μg∙m-3) using a stationary network of 6 monitors measuring minute concentration of PM2.5, In the village Družec, Kladno district, during the 14-day measuring campaign. Campaign average exceeded the limit at the primary school garden. In the other sites, the limit was usually exceeded occasionally except one day, when the limit exceedance was recorded in all the sites as well at the whole area of the Czech Republic. The analysis of time course of minute values of PM2.5 shows that the residential heating increased PM2.5 concentrations on average by 61-72% (16-25 g∙m-3) or 40-49% (6-10 g∙m-3) at exposed or background sites respectively; PM2.5 values decreased exponentially with wind speed up to 2 m∙s-1, when they stabilized at 8-16 g∙m-3. At the microscale of the village, there were also found spatial and temporal heterogeneity of PM2.5 and aerosol particle concentrations PNC using by mobile measurement of PNC...
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Role of aerosol in climate change
Švátora, Milan ; Hůnová, Iva (advisor) ; Hovorka, Jan (referee)
Atmospheric aerosol is a suspension of liquid or solid particles or their mixture in the atmosphere. Tropospheric aerosols can get into the air from its natural sources or from anthropogenic sources. Release of carbon dioxide from burning fossil fuels and organic and elemental carbon from biomass burning are the major anthropogenic sources of aerosols. Primary aerosols have a direct source of emissions (dust from quarries or from land, sea salt particles in the waves, volcanic ash during volcanic eruptions). Secondary aerosols are formed by chemical reactions of substances in the atmosphere, which converts the gas particles - so- called conversion of gases to particles (formation of nitrates by oxidation of nitrogen oxides and sulfates from sulfur dioxide). Atmospheric aerosol is an important component of the atmosphere and contributes to significant atmospheric events, such as precipitation formation and precipation fall, radiation balance of Earth. Aerosols can affect the radiation balance of the Earth in two ways. First, through absorption and scattering of shortwave and long wave radiation - so-called direct effect. Or serve as condensation nuclei on which water is condenses. Aerosols can affect formation, quantity, length of existence and radiation properties of clouds - so-called indirect effect. In...
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The impact of building isolation on CO2 concentration in flats
Čejková, Eliška ; Hovorka, Jan (advisor) ; Holcátová, Ivana (referee)
1 ABSTRACT This diploma work investigates the influence of thermal insolation at residential buildings on the concentration of CO2 (carbon dioxide) in indoor environment. The studied area is a housing estate of panel buildings (flats) in Sezimovo Ústí city. The present work notices a positive impact of thermal insolation on energy demands of buildings and it is mainly saving consumed heat energy which is also connected with emission lowering of carbon dioxide emissions. The main problem which is soluted in the work is that total insolation is usually done without any ventilation solution. It means that it has later a negative impact on indoor environment/air quality in flats. The main part if this work presents measurements of indoor air quality - CO2 concentration, air change rate, temperature and relative humidity in an insolated (with plastic windows) and a non-insolated (with the original wooden windows) flats. The measurement lasted for three days in selected pairs of flats - with plastic and wooden windows. The measuremet took place in bedrooms because the behaviour of residents of households was very similar during their sleep. The air change rate was then caculated from CO2 concentration decay during period of 3 hours without residents. The main aim is to quantify these differences. The conclusion...
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