National Repository of Grey Literature 83 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
PHYSICOCHEMICAL CHARACTERISTICS AND EVOLUTION OF AEROSOL FROM OPEN COMBUSTION OF BIOMASS DURING THE TRADITIONAL “BURNING OF THE WITCHES”
Mbengue, Saliou ; Vodička, Petr ; Komínková, Kateřina ; Schwarz, Jaroslav ; Zíková, Naděžda ; Vítková, Gabriela ; Windell, Laurence Christian ; Suchánková, Lenka ; Lhotka, Radek ; Julaha, Kajal ; Prokeš, Roman ; Šmejkalová Holubová, A. ; Ondráček, Jakub ; Ždímal, Vladimír ; Holoubek, Ivan
Open biomass burning (OBB) is a major source releasing large quantities of gaseous and particulate pollutants into the atmosphere, with global, regional and local impacts on air quality, public health and climate (Andreae, 2019, Chen et al., 2017). OBB aerosols mainly consist of carbonaceous matter, and a considerable amount of inorganic salts, which present distinctly different optical properties (Chen et al., 2017, Reid et al., 2005). In this study, we investigate the influence of OBB during the traditional Burning of the Witches (BoW), referred to in Czech as “Pálení čarodějnic”, on the physico-chemical properties of atmospheric aerosols collected at the National Atmospheric Observatory Košetice (NAOK). The BoW is a centuries-old pagan tradition very popular in the Czech Republic. Today, it is celebrated during the night from April 30 to May 1 by lighting bonfires made of woodpiles with fake witches.
WATER-SOLUBLE COMPOUNDS PM2.5 AT THREE RURAL BACKGROUND SITES IN CENTRAL EUROPE DURING COLD AND WARM PERIODS
Schwarz, Jaroslav ; Vodička, Petr ; Lhotka, Radek ; Pokorná, Petra ; Zíková, Naděžda ; Ondráček, Jakub ; Aurora, S. ; Poulain, L. ; Herrmann, H. ; Ždímal, Vladimír
Ion chromatography (IC) was used to characterize water soluble compounds in PM2.5 during winter and summer campaigns at three rural sites in Central Europe in 12-hour (day/night) time resolution. Concentrations of biomass combustion aerosolsdoubled from Melpitz to Košetice in winter, sea salt exhibited opposite behaviour. Summer exhibited higher sulphates and methane sulphonic acid in Melpitz. Day to night ratios showed higher day concentrations for phosphates and compounds connected to fungal spores and bacteria, while higher night concentrations were connected to wood combustion. Ventilation index was used as an approximate measure to distinguish local and long range transported aerosols. Biomass combustion products were identified as the \nmajority of local aerosols, while sea salt as long range transported one.
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TRACERS OF ANTHROPOGENIC AND BIOGENIC SOURCES OF ORGANIC AEROSOL IN THE PM1 FRACTION AT THE KOŠETICE BACKGROUND STATION
Vodička, Petr ; Kawamura, K. ; Deshmukh, D.K. ; Pokorná, Petra ; Schwarz, Jaroslav ; Ždímal, Vladimír
In this study, we have examined in detail the seasonal changes in the concentration of sugars, dicarboxylic acids and their oxidation precursors in fine aerosol at a rural Central European background site. The aim of the study was to identify typical tracers for different sources of organic aerosol and to determine their contributions to organic PM1.We found a clear difference between winter and summer PM1 aerosol composition at the molecular level. Subsequently, we identified two biogenic factors (dominant in summer), two anthropogenic factors (major contribution in winter) and one background factor.\nMore details could be found in Vodička et. al (2023).
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SUBMICRON AEROSOL AT TWO URBAN STATIONS IN PRAGUE
Pokorná, Petra ; Zíková, Naděžda ; Vodička, Petr ; Lhotka, Radek ; Ondráček, Jakub ; Schwarz, Jaroslav ; Ždímal, Vladimír ; Hopke, P.
The aim of this work was to determine the submicron aerosol dynamics, chemical compositions, and origins at two sites in Prague based on the particle number size distribution (PNSD) and chemical composition of 2/12/24h atmospheric aerosol samples (PM1) collected in parallel for half-year/within two seasons at two urban sites (suburban – Suchdol and traffic – Vršovice). Chemical analysis of PM1 for carbon (elemental, equivalent black – eBC and organic) by thermo-optical method and for water-soluble inorganic ions by IC was performed. For most months, both number and mass median \nconcentrations based on the SMPS data differed. Higher eBC concentrations were measured in Vršovice however eBC concentrations showed good correlation (r=0.80, yintercept=0) at the two stations. Higher average PM1 at the traffic site in summer and at the suburban site in winter, and seasonal differences in ionic PM1 composition reflected the seasonality of the local sources. Nevertheless, there were no statistically significant differences in PM1 concentration and ionic composition between the sites.
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HIGHLY-TIME RESOLVED ELEMENTAL SOURCE APPORTIONMENT OF PM2.5 AT AN URBAN TRAFFIC SITE IN PRAGUE
Windell, Laurence Christian ; Pokorná, Petra ; Ondráček, Jakub ; Schwarz, Jaroslav ; Lhotka, Radek ; Vodička, Petr ; Zíková, Naděžda ; Hopke, P.K. ; Ždímal, Vladimír
This work aims to quantify metal emissions from traffic at an urban traffic site in Prague, Czech Republic, identify key tracers of emissions, and investigate exhaust and non-exhaust emissions observable in fine particulate matter (PM2.5). This project signifies the first high-time resolution elemental analysis of Prague aerosols.
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Monitoring of mutant huntingtin influence on autophagy in human neural stem cells
Zezulová, Kristýna ; Vodička, Petr (advisor) ; Kohoutek, Jiří (referee)
Huntington's disease is an inherited neurodegenerative disease caused by a mutation in the huntingtin gene. Its expressed product, mutated huntingtin protein, aggregates in the cell and affects wide range of cellular processes, including proteostasis mechanisms. Autophagy, classified among the mechanisms of cellular degradation and recycling of proteins and other cellular components, is one of the processes disrupted by the presence of mutated huntingtin. The goal of the project was to prepare a tandem genetic construct (fusion protein LC3-EGFP-mCherry) using chemically competent bacteria by molecular cloning methods, transfect it into prepared human lines carrying both normal and mutated huntingtin, and thus modify the lines to transiently, and if possible also constantly express this sensor of autophagy activity. Such modified lines allow monitoring the effect of the presence of normal and mutated HTT on the course of autophagy and also provide experimentally suitable conditions for influencing autophagy in these cells using inhibitors and activators from the group of small molecules. Two types of LC3-GFP-mCherry/RFP fusion proteins were successfully prepared by molecular cloning and transiently introduced by lipofection into the control ARPE19 lines. Expression of the constructs in human H9 NSC...
The impact of covid-19 restrictions on carbonaceous aerosols at rural background site: importance of vertical distribution
Mbengue, Saliou ; Vodička, Petr ; Komínková, Kateřina ; Schwarz, Jaroslav ; Zíková, Naděžda ; Prokeš, Roman ; Suchánková, Lenka ; Julaha, Kajal ; Ondráček, Jakub ; Holoubek, Ivan ; Ždímal, Vladimír
In this study, EC and OC at 4 m elevation and EC at 230 m elevation showed a similar \nseasonal pattern with higher values in winter and lower values in summer. OC, measured \nat 230 m height showed an opposite behavior with slightly higher values in spring and \nsummer, probably related to the increased contribution of secondary organic carbon \n(SOC). Concentrations were generally higher at 4 m, where there was also a better \ncorrelation between EC and OC, suggesting a greater influence of local sources near the \nsurface.
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NMR Aerosolomics Study of Water-Soluble Organic Compounds in Size-Resolved Particulate Matter
Horník, Štěpán ; Vodička, Petr ; Pokorná, Petra ; Schwarz, Jaroslav ; Ždímal, Vladimír ; Sýkora, Jan
Organic aerosols (OA) account for a significant fraction (10 – 90%) of atmospheric particulate matter (Hallquist et al., 2009). The composition of organic aerosols is very complex and is usually characterized by their water solubility. Water-soluble organic compounds (WSOC) constitute a large fraction of OA (10 – 80%) and consist of chemical species containing oxygenated functional groups such as hydroxyl, carboxyl, or carbonyl groups. NMR spectroscopy represents an alternative to commonly used techniques (gas chromatography-mass spectrometry, liquid chromatography-based techniques) for WSOC analysis. Our recently introduced method, called NMR aerosolomics, allows quantitative analysis of dozens of individual compounds from different aerosol samples. An important part of the characterization of aerosols is their classification by particle size. The analysis of individual compounds in the size-resolved fractions of the WSOC class has been performed only in a few studies that focus mainly on a particular subclass of compounds or use multiple analytical techniques.
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Physicochemical Properties and Origin of PM1 Measured at a Rural Background Site
Pokorná, Petra ; Zíková, Naděžda ; Vodička, Petr ; Lhotka, Radek ; Mbengue, Saliou ; Holubová Šmejkalová, A. ; Riffault, V. ; Ondráček, Jakub ; Schwarz, Jaroslav ; Ždímal, Vladimír
This study assesses the variability of organic aerosol (OA) sources monitored at the rural background site Frýdlant. Non-refractory PM1 was evaluated in two seasons of\n2021. The positive matrix factorization with the multi-linear engine was used to determine the sources of OA at Frýdlant site, with four factors resolved both in winter and\nsummer.
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Chemical composition and sources of atmospheric aerosols at the Frýdlant background station
Lhotka, Radek ; Pokorná, Petra ; Vodička, Petr ; Zíková, Naděžda ; Ondráček, Jakub ; Arora, S. ; Poulain, L. ; Hermann, H. ; Schwarz, Jaroslav ; Ždímal, Vladimír
This study assesses the variability of organic aerosol (OA) sources monitored at the rural background site Frýdlant. Non-refractory PM1 was evaluated in two seasons of\n2021. The positive matrix factorization with the multi-linear engine was used to determine the sources of OA at Frýdlant site, with four factors resolved both in winter and\nsummer.
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8 Vodička, Pavel
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