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Three Years of Experience with Measurement of Cloud Condensation Nuclei Concentrations Using Cloud Condensation Nuclei Counter CCN-200
Moravec, Pavel ; Lhotka, Radek ; Ždímal, Vladimír
Aerosol particles in the atmosphere that allow water vapor to condense and form cloud droplets are called Cloud Condensation Nuclei (CCN). Elevated concentrations of \nCCN tend to increase the concentration and decrease the size of droplets. This can lead to suppression of precipitation in shallow and short-lived clouds and to greater convective \noverturning and more precipitation in deep convective clouds. The response of cloud properties and precipitation processes to increasing anthropogenic aerosol concentrations represents one of the largest uncertainties in the current understanding of climate change. One of the fundamental challenges is to determine the ability of aerosol particles to act as CCN under relevant atmospheric conditions. Knowledge of the spatial and temporal distribution in the atmosphere is essential to incorporate the effects of CCN into meteorological models of all scales, Huang et al. (2007). Long-term CCN measurements are performed at aerosol monitoring sites such as those forming ACTRIS (Aerosols, Clouds and Trace Gases Research Infrastructure) network. In this paper, we present the three-year experience of measuring CCN concentrations over the National Atmospheric Observatory Košetice (NAOK), a rural background site in the Czech Republic. The first results of these measurements were presented by Mishra et al. (2022)
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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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Dependence of aerosol activation on meteorological conditions
Zíková, Naděžda ; Pokorná, Petra ; Sedlák, Pavel ; Ždímal, Vladimír
Four intensive in-situ campaigns focused on aerosol-cloud interactions were performed in the autumn and spring months from Nov 2018 to Apr 2020 at Milešovka Mountain in Czechia to bring more insight into size-dependent aerosol activation and dependence on its origin for a wide variety of meteorological parameters. Most activated particles were larger than 100 nm, with a mode over 200 nm. For the description of the changes in the activation, no effect of photochemistry was found, in contrast, some dependence on relative humidity, temperature, wind speed, and liquid water content (LWC) proved to be useful. The strongest connection was found between activation and LWC. For LWC below 0.1 g/m3, in the LWC-limited regime, the LWC values and variables effecting the LWC were the main factors influencing the activation, while different parameters could have played a role at LWCs over 0.1 g/m3, in the LWC-independent regime.
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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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10-year monitoring of oxidative stress in people professionally exposed to nanoparticles using non-invasive methods
Pelclová, D. ; Ždímal, Vladimír
Elemental contents were analyzed by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM /EDS). The total particle number concentration \nranged from 1.98x104 to 5.4x105/cm3 and the nanoparticle fraction was 40-95%. Panels of oxidative stress biomarkers in the form of lipids, nucleic acids and protein damage were analyzed in exhaled breath condensate (EBC), plasma and urine pre-shift and post-shift using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS /MS). Markers for oxidation of lipids, nucleic acids, and proteins in EBC and plasma were already elevated in pre-shift samples (p < 0.05) of workers compared to controls and showed additional post-shift elevation. The best time to collect all samples is post-shift at the end of the work week. Then, markers of oxidative stress in all three \nbiological fluids, including urine, reflect both acute (cross-shift) and chronic effects of exposure.
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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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Planetary Boundari Layer Effect on Vertical Transport of Black Carbon Concentration under Different Meteorological Conditions
Julaha, Kajal ; Zíková, Naděžda ; Mbengue, Saliou ; Ždímal, Vladimír
In the present study, we analyzed the impact of equivalent black carbon (eBC) aerosols at two different heights (4 m and 230 m) on the PBL height under different \nmetrological conditions such as clear sky, foggy (visibility ≤ 1km), and hazy days (visibility ≤ 8km during the non-fog day), high relative humidity, temperature, and \nobservational data, also, diurnal and seasonal variability was evaluated.
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A Seven-Years Based Characterization of Aerosol Light Scattering Properties at Central European Rural Site: Variability and Source Apportionment
Suchánková, Lenka ; Mbengue, S. ; Zíková, Naděžda ; Ondráček, Jakub ; Holubová Šmejkalová, A. ; Prokeš, R. ; Holoubek, I. ; Ždímal, Vladimír
The aim of this study is to focus on the temporal variations of light-scattering properties of aerosols at a rural background site in Central Europe. The total light scattering (σsp) and backscattering (σbsp) coefficients and associated calculated optical properties such as the Ångström exponent (SAE), the backscattering ratio (b), and the asymmetry factor (g), are characterized considering different time scales (annual, seasonal, monthly, or diurnal) based on long-term measurement. The optical properties were compared with meteorological conditions (fog, cloudiness), the concentrations of gaseous pollutants such as NOx and SO2 were inspected as well as potential sources of atmospheric aerosols. In addition, radiative forcing, and the influence of other meteorological conditions (e.g., height of planetary boundary layer), chemical composition and particle size distribution at the National Atmospheric Observatory Košetice (NAOK) are being further investigated to better understand the direct effects of aerosols on the local climate.
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The Story of Teamwork and the Birth of the FFP* (Filter Backpack)
Fraenkl, M. ; Krbal, M. ; Houdek, J. ; Zmrhalová, Z. ; Prokeš, B. ; Hejda, P. ; Slang, S. ; Přikryl, J. ; Ondráček, Jakub ; Makeš, Otakar ; Kostyk, Juraj ; Nasadil, P. ; Malčík, P. ; Ždímal, Vladimír ; Vlček, M.
Soon after the outbreak of the coronavirus crisis in the Czech Republic and the first lockdown (2020), we enthusiastically decided to fight the coronavirus with scientific \nmeans. Originally materials engineers, we decided to develop an effective protective respiratory device, which was in short supply at the time. We soon found out, that every textile material (handkerchief 10%) has a certain ability to catch an aerosol particle carrying the corona virus, the slower the aerosol particle (d<300 nm) passes through the filter, the greater the chance it has of being caught, with the thickness of the filter, the amount of passed particles decreases exponentially and breathing resistance increases linearly. On this basis, we decided to experiment with a large-area filter placed on the user's back (it wouldn't fit anywhere else) and commercially available textile filter material.
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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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2 Ždímal, V.
1 Ždímal, Václav
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