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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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Energy saving buildings
Raška, David ; Přibil, Rudolf (advisor) ; Hovorka, Jan (referee)
Práce se zabývá problematikou nízkoenergetických a pasivních domů, včetně předložení důvodů pro jejich výstavbu. Poukazuje na jejich vlastnosti a sledované parametry pro splnění požadovaných hodnot. Dále pojednává o nejdůležitějších podmínkách pro výběr polohy energeticky efektivních staveb a o doporučeném zónování místností dle světových stran v závislosti na slunečním záření. Uvádí možnosti složení konstrukčních částí a nejčastěji používané výtopné systémy pro energeticky efektivní stavby, které jsou svým provozem šetrnější k životnímu prostředí. Cílem je předložit ucelenou informaci o daném tématu tak, aby bylo možno vyvozovat závěry podporující praktické využití těchto staveb, a to především z hlediska potenciálu značných energetických úspor. Práce rovněž vypovídá o vývoji výstavby energeticky úsporných budov v České republice. Abstract: This work is concerned with questions of energy saving buildings, including introduction of reasons for their building-up. It refers about their characteristics and evaluated parameters for meeting it's requirements. Further it deals with the most important conditions for choosing of location for energy saving buildings and about recommended zoning of rooms according to cardinal points depending on solar radiation. Indicates the posibilities of composition...
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Trends of ambient ozone in the Northern hemisphere
Bučková, Nicole ; Hůnová, Iva (advisor) ; Hovorka, Jan (referee)
The development of ground-level ozone concentrations is currently hotly debated topic. Ozone itself is highly toxic and has strong oxidizing effects. Ozone has negative impact on human health, but also on vegetation. In addition ozone is one of the most important greenhouse gases causing the greenhouse effect. The Council of Europe decided to limit its increasing tendency by the release of Directive 2002/3/EC. Limits that are set in this Directive are binding for all Member States without exception and breach of these limits is enforceable by law. However as a result of increased anthropogenic activities, particularly increased consumption of fossil fuels and the development of industrialization, those limits are very often breached. Especially in summer when is solar radiation is most intense. This suggests that the highest ozone concentrations are in southern Europe. North Europe has problems with intercontinental transport of ozone. Concentration of ozone is dependent on many factors - the weather conditions, the geography but also the impact from human activity. This paper describes the development of ground-level ozone concentrations in various regions in Europe and North America. In writing this work, I come out mainly from foreign studies that address this topic. Keywords: ozone,...
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Resuspension chamber as a tool for determination of resuspendable fraction of soil and street dust
Civiš, Martin ; Hovorka, Jan (advisor) ; Ždímal, Vladimír (referee) ; Střižík, Michal (referee)
A purpose-built cylindrical resuspension chamber (V=0.437 m3 , S=0.35 m2 , S/V=8.38) was used for the dispersion of samples of soil and various kinds of dust. The samples were studied from the point of view of the number and mass distribution of aerosol particles which could affect the concentration of atmospheric aerosol. The samples were taken from lignite, power plant flue ash and from overburden soil in the North Bohemian surface mine Nastup. The individual samples were pneumatically dispersed inside the chamber under defined temperature-humidity conditions (20řC and relative humidity (RH) 50 %). An APS (Aerodynamic Particle Sizer) processing provided us with average size distributions of particle mass and number. Lignite and flue ash probably have the greatest potential impact on the concentration of atmospheric aerosol in the studied locality. The amount of the resuspended mass of the samples varied between 0.001 % (overburden soil) and 0.32 % (mine road). The lignite and flue ash samples were then analyzed by gravimetric methods using the HI (Harvard Impactor) and the SCI (Sioutas Cascade Impactor). The flue ash contained higher amounts of fine particles than the lignite. Subsequent chemical analysis by electron microscope of the filters with deposits of power plant flue ash showed that the PM2.5...
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Family in modern American drama
Hovorka, Jan ; Wallace, Clare (advisor) ; Ulmanová, Hana (referee)
This work analyses the American family in context of society and its demands. It focuses on the cannonical works of the Modern American drama, namely plays of Tennessee Williams, Arthur Miller, Edward Albee, Sam Shepard and David Mamet. The playwrights are analysed in two distinctive groups according to similar themes they share. Tennessee Williams and Arthur Miller depict the family under increasing pressure from the outside as well from the inside. The unit disintegrates, members of the family escape and thus the unit loses its funtions. The pressure is imposed by the tenets of the American mythology that governs the society, which, in turn, influences the family. The common theme of the first group of playwrights is the feeling of loss. This comprises of two dimensions - spatial and tempoval. The second group of playwrights share the same theme of loss with its spatial and temporal implications. They are characteristic by their distinctive use of language that depicts the prevalent sense of doom, apocalypse, futility and sterility. The search for identity is also implied by the restlessness of characters. The detrimental effect of harsh business environment on the family is explored with regards to masculinity. The work shows the family in the context of the 1950s, an era when the family was elevated to...
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Elemental carbon in highly time and size resolved atmosheric aerosol by image analysis
Voldánová, Zdeňka ; Hovorka, Jan (advisor) ; Schwarz, Jaroslav (referee)
In this study a new optical method for highly time and size resolved atmospheric elemental carbon has been described. For this purpose has been used image analysis of 3 DRUM strips with three size fractions deposited (2,5-1,15 µm; 1,15-0,34 µm; 0,34-0,1 µm). Strips were scanned by Fotoscanner HP ScanJet 8200 with optical resolution of 600 dpi. For the analysis of images Matlab program was used, in which the images are transformed to a matrix of grayscale values. The output of this program are time series of grayscale values for each transformed image. Because the time series consist of data in 5 minute intervals, for comparing with hourly PM2,5 EC data obtained from the Sunset EC/OC analyzer, it was necessary to have hourly time series. The precise method of this new approach to determine concentration of atmospheric BC is described in this thesis. In addition, it contains description of the procedures connected with calibrations and controls of sectional outputs. Using linear regression, the daily averages for black carbon are compared with daily EC data. Similarly, hour averages are compared by linear regression also. The analysis performed proved very good relation between daily EC and daily BC described by formula (EC ~ 1.0399 + 0,0117*BC). In respect to hourly averages, a very different...
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The effect of local heating on indoor and outdoor air quality in a rural settlement
Kozáková, Jana ; Braniš, Martin (advisor) ; Hovorka, Jan (referee)
Increased concentrations of particulate matter do not occur in urban areas only, they occur in winter time episodes of high concentrations in small settlements, as well. It is probably caused by usage of solid fuels in domestic heating. The indoor air quality is closely influenced by the outdoor air pollution. Concentrations of size-separated PM were measured by a cascade impactor (PCIS) during two winter and one summer seasons in the years 2009 and 2010 in a village Svrčovec situated near the town Klatovy. Continuous concentrations of PM2.5 were measured in parallel by using a commercial photometer DustTrak. Following meteorological parameters were monitoring - temperature, relative humidity, wind velocity, wind direction, precipitation and sun radiation. The presence of persons and their activities in the house were noted. The average PM10 concentrations in Svrčovec were higher than average PM10 concentration in Klatovy. The summer average PM10 concentrations in Svrčovec were lower than the concentrations in the town (15.5 μg/m3, 17.4 μg/m3) and the winter PM10 concentrations in Svrčovec were significantly higher (31.1 μg/m3, 24.3 μg/m3). The average indoor concentrations (PM10 and PM2.5) were lower in the summer (9.6 μg/m3, 8.3 μg/m3) than in the winter season (24.0 μg/m3, 20.7...
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Estimating infiltration of quasi-ultrafine aerosol by the absorbance method: Air quality in schools
Stehlíková, Pavla ; Braniš, Martin (advisor) ; Hovorka, Jan (referee)
Estimating infiltration of quasi-ultrafine black carbon particles by an absorbance method: air quality in Pavla Stehlíková Abstract This diploma thesis focused on the estimating quasi-ultrafine particles amount in school gyms continue previous study researched air quality in schools. The size-segregated mass concentration of particulate matter was measured in three elementary school gyms in central part of Prague, on periphery of Prague and in a small settlement Černošice during twenty campaigns, from 2005 to 2009. The mass concentration of particulate matter were measured by 5-staged Sioutas impactor. For this thesis we have selected samples on filters with particle size <0,25µm. To evaluate carbonaceous particles amount we used reflectance. Reflectance was transformed into an absorption coefficient (m- 1 .10-5 ). The average levels of absorptions coeficients were higher outdoors (14,66 ± 8,93 m- 1 .10-5 ) than indoors (13,64 ± 8,08 m-1 .10-5 ). The correlations between absorption coeffitients outdoors and indoors were significant for all schools (Spearman's correlation coefficient at intervals 0,834-0,957, regression slope 0,759-1,007), suggesting a high outdoor-to-indoor penetration rate. The weak correlation between absorption coefficients and number of exercising pupils (correlation coefficient 0,059)...
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Seasonal and microscale variability of PM1 and PM10
Grégr, Michal ; Hovorka, Jan (advisor) ; Braniš, Martin (referee)
The master thesis evaluates the middle scale spatial/seasonal variability of PM1 and PM10 at four sampling localities. Statistical significant differences in PM values could be crucial for a representative placement of a measuring station at the locality. A set of 7 portable laser nephelometers DustTrak - DT (8520, TSI) was used to record 5 minute integrates of PM1 and PM10 consecutively for each size for 3 days at 4 localities. The localities were rural, urban, background and freeway and contrasted as far as the main aerosol sources are concerned. At each locality, inter-DT distances ranged from 30 - 500m, 80 - 220m, 70 - 150m, and 30m and total area covered 290 000 m2 , 57 000 m2 , 29 000m2 , 240m2 in rural, urban, background and freeway locality, respectively. Wilcoxon signed-ranks test for 2 dependent samples was used to evaluate the variability. As expected, PM1 did not vary statistically significantly (α=0.05) among DT's at all localities in both winter and summer. Contrary to PM1, inter-DT PM10 values varied significantly at background and rural localities, according to the Wilcoxon test. These differences occurred in 3 out of 50 possibilities for winter measurements. However, there is no statistically significant difference in median values comparison.
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