Particle characterization
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Systematic characterization of morphological, mineralogical, chemical and toxicological properties of various size fractions of the atmospheric particulate matter was a main focus of this study together with an assessment of the human health risks they pose. Even though near-ground atmospheric aerosols have been a subject of intensive research in recent years, data integrating chemical composition of particles and health risks are still scarce and the particle size aspect has not been properly addressed yet. Filling this gap, however, is necessary for reliable risk assessment. A high volume ambient air sampler equipped with a multi-stage cascade impactor was used for size specific particle collection, and all 6 fractions were a subject of detailed characterization of chemical (PAHs) and mineralogical composition of the particles, their mass size distribution and genotoxic potential of organic extracts. Finally, the risk level for inhalation exposure associated to the carcinogenic character of the studied PAHs has been assessed. The finest fraction (<0.45 μm) exhibited the highest mass, highest active surface, highest amount of associated PAHs and also highest direct and indirect genotoxic potentials in our model air sample. Risk assessment of inhalation scenario indicates the significant cancer risk values in PM 1.5 size fraction. This presented new approach proved to be a useful tool for human health risk assessment in the areas with significant levels of air dust concentration.
- MeSH
- aerosoly chemie toxicita MeSH
- chemické modely MeSH
- hodnocení rizik MeSH
- inhalační expozice statistika a číselné údaje MeSH
- látky znečišťující vzduch chemie toxicita MeSH
- lidé MeSH
- monitorování životního prostředí MeSH
- pevné částice chemie toxicita MeSH
- polycyklické aromatické uhlovodíky analýza chemie toxicita MeSH
- testy toxicity MeSH
- velikost částic MeSH
- vzduch analýza MeSH
- znečištění ovzduší statistika a číselné údaje MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Exhaust emissions of 23 individual city buses at Euro III, Euro IV and EEV (Enhanced Environmentally Friendly Vehicle) emission levels were measured by the chasing method under real-world conditions at a depot area and on the normal route of bus line 24 in Helsinki. The buses represented different technologies from the viewpoint of engines, exhaust after-treatment systems (ATS) and fuels. Some of the EEV buses were fueled by diesel, diesel-electric, ethanol (RED95) and compressed natural gas (CNG). At the depot area the emission factors were in the range of 0.3-21 × 10(14) # (kg fuel)(-1), 6-40 g (kg fuel)(-1), 0.004-0.88 g (kg fuel)(-1), 0.004-0.56 g (kg fuel)(-1), 0.01-1.2 g (kg fuel)(-1), for particle number (EFN), nitrogen oxides (EFNOx), black carbon (EFBC), organics (EFOrg), and particle mass (EFPM1), respectively. The highest particulate emissions were observed from the Euro III and Euro IV buses and the lowest from the ethanol and CNG-fueled buses, which emitted BC only during acceleration. The organics emitted from the CNG-fueled buses were clearly less oxidized compared to the other bus types. The bus line experiments showed that lowest emissions were obtained from the ethanol-fueled buses whereas large variation existed between individual buses of the same type indicating that the operating conditions by drivers had large effect on the emissions.
- MeSH
- látky znečišťující vzduch analýza chemie MeSH
- molekulová hmotnost MeSH
- motorová vozidla * MeSH
- velkoměsta MeSH
- výfukové emise vozidel analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Finsko MeSH
- velkoměsta MeSH
Effects of airborne particles on the expression status of markers of cellular toxic stress and on the release of eicosanoids, linked with inflammation and oxidative damage, remain poorly characterized. Therefore, we proposed a set of various methodological approaches in order to address complexity of PM0.5-induced toxicity. For this purpose, we used a well-characterized model of A549 pulmonary epithelial cells exposed to a non-cytotoxic concentration of ambient aerosol particle fraction PM0.5 for 24 h. Electron microscopy confirmed accumulation of PM0.5 within A549 cells, yet, autophagy was not induced. Expression profiles of various cellular stress response genes that have been previously shown to be involved in early stress responses, namely unfolded protein response, DNA damage response, and in aryl hydrocarbon receptor (AhR) and p53 signaling, were analyzed. This analysis revealed induction of GREM1, EGR1, CYP1A1, CDK1A, PUMA, NOXA and GDF15 and suppression of SOX9 in response to PM0.5 exposure. Analysis of eicosanoids showed no oxidative damage and only a weak anti-inflammatory response. In conclusion, this study helps to identify novel gene markers, GREM1, EGR1, GDF15 and SOX9, that may represent a valuable tool for routine testing of PM0.5-induced in vitro toxicity in lung epithelial cells.
- MeSH
- aerosoly MeSH
- buňky A549 MeSH
- epitelové buňky metabolismus patologie MeSH
- látky znečišťující vzduch toxicita MeSH
- lidé MeSH
- pevné částice toxicita MeSH
- plíce metabolismus patologie MeSH
- regulace genové exprese účinky léků MeSH
- signální transdukce účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The aim of this study was to evaluate the nanoparticle emissions from a laser printer in a chamber in conjunction with emissions from printers in a print room (PR) and to characterize the processes that lead to increased nanoparticle concentrations, as well as to estimate the human particle dose of the printers' users. Measurements were conducted in a small stainless steel environmental chamber under controlled conditions, where the evolution of particle size distributions (PSDs) with time and printed pages was studied in detail. Printer was generating nanoparticles (vast majority ˂ 50 nm with mode on ~ 15 nm) primarily during cold startup. Previously, 1-week sampling was also done in a PR at the Technical University of Crete, where the tested laser printer is installed along with three other printers. Similarly, as it was observed in the chamber study, printers' startup on any given day was characterized by a sharp increase in particle number (PN) concentrations. Average measured PN concentrations during printing hours in PR (5.4 × 103 #/cm3) is similar to the one observed in chamber measurements (6.7 × 103 #/cm3). The ExDoM2 dosimetry model was further applied to calculate the deposition of particles in the human respiratory tract. More precisely, the increase in particle dose for an adult Caucasian male was 14.6- and 24.1-fold at printers' startup, and 1.2- and 5.2-fold during printing in the PR and experimental chamber, respectively, compared to the exposure dose at background concentrations (BCs).
- MeSH
- inhalační expozice analýza MeSH
- lidé MeSH
- nanočástice analýza MeSH
- pevné částice analýza MeSH
- teoretické modely * MeSH
- tiskařství MeSH
- velikost částic MeSH
- vystavení vlivu životního prostředí analýza MeSH
- znečištění vzduchu ve vnitřním prostředí analýza MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Currently, widely available three-dimensional (3D) printers are very popular with the public. Previous research has shown that these printers can emit ultrafine particles (UFPs) and volatile organic compounds (VOCs). Several studies have examined the emissivity of filaments from 3D printing, except glycol modified polyethylene terephthalate (PETG) and styrene free co-polyester (NGEN) filaments. The aim of this study was to evaluate UFP and VOC emissions when printing using a commonly available 3D printer (ORIGINAL PRUSA i3 MK2 printer) using PETG and NGEN. The concentrations of UFPs were determined via measurements of particle number concentration and size distribution. A thermal analysis was carried out to ascertain whether signs of fiber decomposition would occur at printing temperatures. The total amount of VOCs was determined using a photoionization detector, and qualitatively analyzed via gas chromatography-mass spectrometry. The total particle concentrations were 3.88 × 1010 particles for PETG and 6.01 × 109 particles for NGEN. VOCs at very low concentrations were detected in both filaments, namely ethylbenzene, toluene, and xylene. In addition, styrene was identified in PETG. On the basis of our results, we recommend conducting additional measurements, to more accurately quantify personal exposure to both UFPs and VOCs, focusing on longer exposure as it can be a source of potential cancer risk.
- Klíčová slova
- velikostní distribuce hmoty aerosolu, městské ovzduší,
- MeSH
- aerosoly MeSH
- lidé MeSH
- monitorování životního prostředí MeSH
- pevné částice klasifikace MeSH
- polycyklické aromatické uhlovodíky * škodlivé účinky toxicita MeSH
- roční období MeSH
- smog analýza MeSH
- znečištění ovzduší * analýza statistika a číselné údaje škodlivé účinky MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
BACKGROUND: Secondary organic aerosols (SOAs) formed from anthropogenic or biogenic gaseous precursors in the atmosphere substantially contribute to the ambient fine particulate matter [PM ≤2.5μm in aerodynamic diameter (PM2.5)] burden, which has been associated with adverse human health effects. However, there is only limited evidence on their differential toxicological impact. OBJECTIVES: We aimed to discriminate toxicological effects of aerosols generated by atmospheric aging on combustion soot particles (SPs) of gaseous biogenic (β-pinene) or anthropogenic (naphthalene) precursors in two different lung cell models exposed at the air-liquid interface (ALI). METHODS: Mono- or cocultures of lung epithelial cells (A549) and endothelial cells (EA.hy926) were exposed at the ALI for 4 h to different aerosol concentrations of a photochemically aged mixture of primary combustion SP and β-pinene (SOAβPIN-SP) or naphthalene (SOANAP-SP). The internally mixed soot/SOA particles were comprehensively characterized in terms of their physical and chemical properties. We conducted toxicity tests to determine cytotoxicity, intracellular oxidative stress, primary and secondary genotoxicity, as well as inflammatory and angiogenic effects. RESULTS: We observed considerable toxicity-related outcomes in cells treated with either SOA type. Greater adverse effects were measured for SOANAP-SP compared with SOAβPIN-SP in both cell models, whereas the nano-sized soot cores alone showed only minor effects. At the functional level, we found that SOANAP-SP augmented the secretion of malondialdehyde and interleukin-8 and may have induced the activation of endothelial cells in the coculture system. This activation was confirmed by comet assay, suggesting secondary genotoxicity and greater angiogenic potential. Chemical characterization of PM revealed distinct qualitative differences in the composition of the two secondary aerosol types. DISCUSSION: In this study using A549 and EA.hy926 cells exposed at ALI, SOA compounds had greater toxicity than primary SPs. Photochemical aging of naphthalene was associated with the formation of more oxidized, more aromatic SOAs with a higher oxidative potential and toxicity compared with β-pinene. Thus, we conclude that the influence of atmospheric chemistry on the chemical PM composition plays a crucial role for the adverse health outcome of emissions. https://doi.org/10.1289/EHP9413.
- MeSH
- aerosoly analýza MeSH
- endoteliální buňky chemie metabolismus MeSH
- látky znečišťující vzduch * analýza toxicita MeSH
- lidé MeSH
- pevné částice analýza MeSH
- plíce metabolismus MeSH
- saze * MeSH
- senioři MeSH
- stárnutí MeSH
- Check Tag
- lidé MeSH
- senioři MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Detonation nanodiamonds (DNDs) are usually small particles of 4–5 nm, but in aqueous suspension, DNDs form agglomerates in sizes larger than 1 μm. We propose the use of Bead Assisted Sonic Disintegration and a carboxylation procedure, to reduce DNDs aggregates sizes to approximately 100 nm. High cost zirconium beads have been substituted by silica beads synthetized in our laboratory and less-time consuming conditions were standardized. Techniques as Dynamic Light Scattering (DLS), Fourier Transform InfraRed Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS), have been used to characterize the resulting diamond nanoparticles. While the incubation of Red Blood Cells with partially disaggregated DNDs was used to study whether these nanodiamonds impact in a living system. Our results show the absence of a negative effect in cell viability as well as no differences between Raman spectra of hemoglobin (Hb), from control and cell + DNDs conditions.
- MeSH
- biokompatibilní materiály MeSH
- krevní buňky cytologie fyziologie MeSH
- nanodiamanty * normy MeSH
- Ramanova spektroskopie metody MeSH
- spektroskopie infračervená s Fourierovou transformací metody MeSH
- testování materiálů MeSH
- ultrazvuk metody přístrojové vybavení MeSH
- velikost částic MeSH
- Publikační typ
- práce podpořená grantem MeSH
Particle size is a key parameter when dealing with drug particle formation, delivery or dissolution. The correct measurement of particle size depends on various factors, such as sample preparation or dilution, but also on the choice of method for its characterization. In this work, we study the process of precipitation of poorly water-soluble drug Valsartan from supersaturated solution in the presence of nonionic surfactant Tween 20. Several techniques including dynamic light scattering (DLS) operated in several measuring modes, optical microscope (OM) and static light scattering (SLS) were used to analyze the kinetics of particle formation. As concluded by the results, the increase in turbidity of the solution seriously limits the application of classical DLS to properly measure the particle size and polydispersity. One way to get around this restriction is by dilution, which however results in a decrease in the size of Valsartan particles in the studied population. In contrast, here we present for a first time technique based on modulated 3D cross correlation DLS equipped with the sample goniometer to determine size of submicron particles of the drug in highly turbid solutions. Additionally, a modified OM was used to measure micron-sized particles for samples without any dilution in a continuous mode. Measured particle sizes combined with measured Valsartan concentration allowed us to identify mechanism responsible for the particle formation from supersaturated solutions. The main mechanism, as it is shown in this work, is covering surface of precipitate particles by the amount of used Tween 20.
