scholarly journals Landfill air pollution by ultrafine and microparticles in case of dry and windless weather conditions

Detritus ◽  
2020 ◽  
pp. 139-146
Author(s):  
Emília Hroncová ◽  
Juraj Ladomerský ◽  
Denisa Ladomerská
Keyword(s):  
Ultrafine Particles ◽  
Large Scale ◽  
Particle Number ◽  
Fine Particles ◽  
Weather Conditions ◽  
Municipal Waste ◽  
Dust Particles ◽  
Particle Sizer ◽  
Ultra Fine Particles ◽  
Surprising Finding

In the present article we give the results for ultra-fine particles and microparticles at a landfill of municipal waste, taking into consideration various factors. The landfill is a large-scale source of dust. There is little knowledge in terms of fractional composition of dust particles. We have performed concentration measurements of the number of ultrafine (10 to 100 nm) and microparticles (0.1 to 10 μm) in the field conditions of the municipal waste landfill using the TSI Technique (Optical particle sizer 3330 and Nanoscan SMPS nanoparticle sizer 3919). The particle number concentration in the atmosphere in case of dry and windless weather conditions at the landfill was in the range of about 2,500 to 5,500 of ultrafine particles per cm3. The mass concentrations of the microparticles was in the range of 29 to 163 μg.m-3 (assuming ρ=1 g.cm-3). There was an evident trend of increase of concentration of the ultrafine particles and microparticles in the lower location of the landfill occuring in the case of dry and windless weather conditions. The surprising finding was that passing haulage vehicles and in particular the operation of the compactor increase the mass concentration of microparticles, but they do not increase the concentration of the number of microparticles or even of ultrafine particles.

Studies of copper selenide ultrafine particles by newly developed gas evaporation method

1990 ◽  
Vol 48 (4) ◽  
pp. 306-307
Author(s):  
Chihiro Kaito ◽  
Yoshio Saito
Keyword(s):  
Crystal Structure ◽  
Ultrafine Particles ◽  
Fine Particles ◽  
Production Method ◽  
Atmospheric Temperature ◽  
Copper Selenide ◽  
Quartz Boat ◽  
Selenium Vapor ◽  
Ar Gas ◽  
Ultra Fine Particles

The direct evaporation of metallic oxides or sulfides does not always given the same compounds with starting material, i.e. decomposition took place. Since the controll of the sulfur or selenium vapors was difficult, a similar production method for oxide particles could not be used for preparation of such compounds in spite of increasing interest in the fields of material science, astrophysics and mineralogy. In the present paper, copper metal was evaporated from a molybdenum silicide heater which was proposed by us to produce the ultra-fine particles in reactive gas as shown schematically in Figure 1. Typical smoke by this method in Ar gas at a pressure of 13 kPa is shown in Figure 2. Since the temperature at a location of a few mm below the heater, maintained at 1400° C , were a few hundred degrees centigrade, the selenium powder in a quartz boat was evaporated at atmospheric temperature just below the heater. The copper vapor that evaporated from the heater was mixed with the stream of selenium vapor,and selenide was formed near the boat. If then condensed by rapid cooling due to the collision with inert gas, thus forming smoke similar to that from the metallic sulfide formation. Particles were collected and studied by a Hitachi H-800 electron microscope.Figure 3 shows typical EM images of the produced copper selenide particles. The morphology was different by the crystal structure, i.e. round shaped plate (CuSe;hexagona1 a=0.39,C=l.723 nm) ,definite shaped p1 ate(Cu5Se4;Orthorhombic;a=0.8227 , b=1.1982 , c=0.641 nm) and a tetrahedron(Cu1.8Se; cubic a=0.5739 nm). In the case of compound ultrafine particles there have been no observation for the particles of the tetrahedron shape. Since the crystal structure of Cu1.8Se is the anti-f1uorite structure, there has no polarity.

Revisiting pulmonary acinar particle transport: convection, sedimentation, diffusion, and their interplay

2015 ◽  
Vol 118 (11) ◽  
pp. 1375-1385 ◽  
Author(s):  
Philipp Hofemeier ◽  
Josué Sznitman
Keyword(s):  
Ultrafine Particles ◽  
Fine Particles ◽  
Particle Sizes ◽  
Transport Dynamics ◽  
Inhaled Particles ◽  
Numerical Studies ◽  
Precise Understanding ◽  
Acinar Structure ◽  
Ultra Fine Particles ◽  
Local Deposition

It is largely acknowledged that inhaled particles ranging from 0.001 to 10 μm are able to reach and deposit in the alveolated regions of the lungs. To date, however, the bulk of numerical studies have focused mainly on micrometer-sized particles whose transport kinematics are governed by convection and sedimentation, thereby capturing only a small fraction of the wider range of aerosols leading to acinar deposition. Too little is still known about the local acinar transport dynamics of inhaled (ultra)fine particles affected by diffusion and convection. Our study aims to fill this gap by numerically simulating the transport characteristics of particle sizes spanning three orders of magnitude (0.01-5 μm) covering diffusive, convective, and gravitational aerosol motion across a multigenerational acinar network. By characterizing the deposition patterns as a function of particle size, we find that submicrometer particles [[Formula: see text] (0.1 μm)] reach deep into the acinar structure and are prone to deposit near alveolar openings; meanwhile, other particle sizes are restricted to accessing alveolar cavities in proximal generations. Our findings underline that a precise understanding of acinar aerosol transport, and ultrafine particles in particular, is contingent upon resolving the complex convective-diffusive interplay in determining their irreversible kinematics and local deposition sites.

Comparison of the uptake of fine and ultrafine TiO2 in a tracheal explant system

1998 ◽  
Vol 274 (1) ◽  
pp. L81-L86 ◽  
Author(s):  
A. Churg ◽  
B. Stevens ◽  
J. L. Wright
Keyword(s):  
Ultrafine Particles ◽  
Particle Number ◽  
Fine Particles ◽  
Particle Uptake ◽  
Pulmonary Epithelial Cells ◽  
Volume Proportion ◽  
Particle Aggregates ◽  
The Relationship ◽  
Ultrafine Tio2 ◽  
Number Of Particles

To examine the relationship between particle uptake by pulmonary epithelial cells and particle size, we exposed rat tracheal explants to fine particles (FPs; 0.12 μm) or ultrafine particles (UFPs; 0.021 μm) of titanium dioxide for 3 or 7 days. By electron microscopy, particles were found in the epithelium at both time points, but in the subepithelial tissues, they were found only at 7 days. The volume proportion of both FPs and UFPs in the epithelium increased from 3 to 7 days; it was greater for UFPs at 3 days but was greater for FPs at 7 days. The volume proportion of particles in the subepithelium at 7 days was equal for both dusts, but the ratio of epithelial to subepithelial volume proportion was ∼2:1 for FPs and 1:1 for UFPs. Mean volume of individual particle aggregates was similar for both dusts at 3 days but was markedly smaller for FPs at 7 days. These observations suggest that the behavior of particles of different size is complex: UFPs persist in the tissues as relatively large aggregates, whereas the size of FP aggregates becomes smaller over time. UFPs appear to enter the epithelium faster, and once in the epithelium, a greater proportion of them is translocated to the subepithelial space compared with FPs. However, if it is assumed that the volume proportion is representative of particle number, the number of particles reaching the interstitial space is directly proportional to the number applied; i.e., overall, there is no preferential transport from lumen to interstitium by size.

scholarly journals Size distribution and hygroscopic properties of aerosol particles from dry-season biomass burning in Amazonia

2005 ◽  
Vol 5 (5) ◽  
pp. 8149-8207 ◽  
Author(s):  
J. Rissler ◽  
A. Vestin ◽  
E. Swietlicki ◽  
G. Fisch ◽  
J. Zhou ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Large Scale ◽  
Particle Number ◽  
Transition Period ◽  
Dry Season ◽  
Diel Variation ◽  
Size Distributions ◽  
Differential Mobility ◽  
Hygroscopic Properties ◽  
Particle Sizer

Abstract. Aerosol particle number size distributions and hygroscopic properties were measured at a pasture site in the southwestern Amazon region (Rondonia). The measurements were performed 11 September–14 November 2002 as part of LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia – SMOke aerosols, Clouds, rainfall and Climate), and cover the later part of the dry season (with heavy biomass burning), a transition period, and the onset of the wet period. Particle number size distributions were measured with a DMPS (Differential Mobility Particle Sizer, 3–850 nm) and an APS (Aerodynamic Particle Sizer), extending the distributions up to 3.3 µm in diameter. An H-TDMA (Hygroscopic Tandem Differential Mobility Analyzer) measured the hygroscopic diameter growth factors (Gf) at 90% relative humidity (RH), for particles with dry diameters (dp) between 20–440 nm, and at several occasions RH scans (30–90% RH) were performed for 165 nm particles. These data provide the most extensive characterization of Amazonian biomass burning aerosol, with respect to particle number size distributions and hygroscopic properties, presented until now. The evolution of the convective boundary layer over the course of the day causes a distinct diel variation in the aerosol physical properties, which was used to get information about the properties of the aerosol at higher altitudes. The number size distributions averaged over the three time periods showed three modes; a nucleation mode with count median diameters (CMD) of ~12 nm, an Aitken mode (CMD = 61–92 nm) and an accumulation mode (CMD = 128–190 nm). The two larger modes were shifted towards larger CMD with increasing influence from biomass burning.

scholarly journals A Hybrid Device for Enhancing Flotation of Fine Particles by Combining Micro-Bubbles with Conventional Bubbles

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 561
Author(s):  
Polyxeni K. Tsave ◽  
Margaritis Kostoglou ◽  
Thodoris D. Karapantsios ◽  
Nikolaos K. Lazaridis
Keyword(s):  
Ultrafine Particles ◽  
Fine Particles ◽  
Mining Industry ◽  
Water Electrolysis ◽  
Collision Efficiency ◽  
Hybrid Device ◽  
Flotation Cell ◽  
Wide Range ◽  
Micro Bubble ◽  
Ultra Fine Particles

Flotation in the mining industry is a very significant separation technique. It is known that fine and ultra-fine particles are difficult to float, leading to losses of valuable minerals, mainly due to their low collision efficiency with bubbles. Flotation of fine particles can be enhanced either by increasing the apparent particle size or by decreasing the bubble size. Literature review reveals that electroflotation resulted in higher recoveries of ultrafine particles as compared with dispersed-air flotation, because electrolytic bubbles are smaller in size. To this end, the best practical approach is to combine conventional air bubbles and micro-bubbles from water electrolysis. Therefore, the design, fabrication, and operation of a bench-scale micro-bubble generator through water electrolysis is proposed. Moreover, this electrolysis unit is adapted in a mechanical Denver-type flotation cell. The resulting hybrid flotation device is capable of producing bubbles within a wide range of diameters. The significance of this process is that micro-bubbles, attached tothe surface of fine particles, facilitate the attachment of conventional-sized bubbles and subsequently increase the flotation recovery of particles. Experimental flotation results so far on the hybrid device indicate the enhancement of fine particle recovery by approximately 10% with the addition of micro-bubbles.

scholarly journals Monitoring of Indoor Ultrafine Particulate Matter at the Sites of the Czech Armed Forces

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Eva KELLNEROVÁ ◽  
Zbyněk VEČEŘA ◽  
Josef KELLNER ◽  
Tomáš ZEMAN
Keyword(s):  
Ultrafine Particles ◽  
Fine Particles ◽  
Working Hours ◽  
Armed Forces ◽  
Ambient Air ◽  
World Health Organisation ◽  
World Health ◽  
Scanning Mobility Particle Sizer ◽  
Adverse Health Effects ◽  
Ultra Fine Particles

Ultrafine particles and nanoparticles in the air are evaluated as a risk factor for the development of respiratory and other healthsymptoms due to their inhalation from the ambient air. The Czech Army professionals are expected to have frequent presence in apolluted environment and regular exposure to air with increased concentration of airborne pollutants. The report evaluates the presenceof ultra-fine particles (in the range of about 7.6–299.6 nm) in rooms often used by soldiers during their working hours whenthey are not deployed. The purpose is to assess whether the presence of troops in these workplaces is safe and does not pose a riskof adverse health effects in itself. Testing took place in three military rooms (classroom 1, classroom 2 and exercise flight simulatorroom). Seven samples of air were analysed in time by the scanning mobility particle sizer in succession. Mean particle concentrationswere found at 1.79×104, 7.53×103 and 8.39×103 N·cm-3 for the classroom 1, classroom 2 and exercise flight simulator room.Conclusions of the research have shown that particle concentrations in the places of the Czech Army can reach values that borderthe immission limits stated by the World Health Organisation.

scholarly journals Large hemispheric difference in ultrafine aerosol concentrations in the lowermost stratosphere at mid and high latitudes

2021 ◽  
Author(s):  
Christina J. Williamson ◽  
Agnieszka Kupc ◽  
Andrew Rollins ◽  
Jan Kazil ◽  
Karl D. Froyd ◽  
...  
Keyword(s):  
Size Distribution ◽  
Ultrafine Particles ◽  
Fine Particles ◽  
Global Scale ◽  
Stratospheric Aerosol ◽  
Heterogeneous Chemistry ◽  
High Latitudes ◽  
Aircraft Emissions ◽  
Ultra Fine Particles ◽  
Ultrafine Aerosol

Abstract. The details of aerosol processes and size distributions in the stratosphere are important for both heterogeneous chemistry and aerosol-radiation interactions. Using in-situ, global-scale measurements of the size distribution of particles with diameters > 3 nm from the NASA Atmospheric Tomography Mission (ATom), we identify a mode of ultrafine aerosol in the lowermost stratosphere (LMS) at mid and high latitudes. This mode is substantial only in the northern hemisphere (NH), and was observed in all four seasons. We also observe elevated SO2, an important precursor for new particle formation (NPF) and growth, in the NH LMS. We use box modelling and thermodynamic calculations to show that NPF can occur in the LMS conditions observed on ATom. Aircraft emissions are shown as likely sources of this SO2, as well as a potential source of ultrafine particles directly emitted by, or formed in the plume of the engines. These ultra-fine particles have the potential to grow to larger sizes, and to coagulate with larger aerosol, affecting heterogeneous chemistry and aerosol-radiation interactions. Understanding all sources and characteristics of stratospheric aerosol is important in the context of anthropogenic climate change as well as proposals for climate intervention via stratospheric sulphur injection. This analysis not only adds to the, currently sparse, observations of the global impact of aviation, but also introduces another aspect of climate influence, namely a size distribution shift of the background aerosol distribution in the LMS.

Fine Particulate Formation During Switchgrass/Coal Cofiring

2005 ◽  
Vol 127 (3) ◽  
pp. 457-463 ◽  
Author(s):  
Linda G. Blevins ◽  
Thomas H. Cauley
Keyword(s):  
Coal Combustion ◽  
Fine Particle ◽  
Mass Concentration ◽  
Particle Number ◽  
Fine Particles ◽  
Combustion Products ◽  
Scanning Mobility Particle Sizer ◽  
Fine Particulate ◽  
Particle Sizer ◽  
Mass Concentrations

Experiments to examine the effects of biomass/coal cofiring on fine particle formation were performed in the Sandia Multi-Fuel Combustor using fuels of pure coal, three combinations of switchgrass and coal, and pure switchgrass. For this work, fine particles with aerodynamic diameter between 10 nm and 1 μm were examined. A constant solid-fuel thermal input of 8 kW was maintained. The combustion products were cooled from 1200 to 420°C during passage through the 4.2 m long reactor to simulate the temperatures experienced in the convection pass of a boiler. Fine particle number densities, mass concentrations, and total integrated number and mass concentrations at the reactor exit were determined using a scanning mobility particle sizer. The fine particle number concentrations for cofiring were much higher than those achieved with dedicated coal combustion. However, the total integrated mass concentration of particles remained essentially constant for all levels of cofiring from 0% coal to 100% coal. The constant mass concentration is significant because pending environmental regulations are likely to be based on particle mass rather than particle size.

PHYTOMONITORING AS A METOD OF THE ASSESSMENT OF ATMOSPHERIC AIR POLLUTION BY URBAN ENVIRONMENT BY FINE DUST

2019 ◽  
pp. 42-53
Author(s):  
Irina Glinyanova ◽  
Valery Azarov ◽  
Valery Fomichev
Keyword(s):  
Urban Environment ◽  
Urban Areas ◽  
Fine Particles ◽  
Prunus Armeniaca ◽  
Dust Particles ◽  
Fine Dust ◽  
Control Zone ◽  
Atmospheric Air ◽  
Random Functions ◽  
The City

Fine dust: (PM2.5, PM10) is a priority pollutant that contributes to the development of numerous dis-eases in urban areas. The purpose of this scientific work is to study the dispersed composition of dust parti-cles on the leaves of apricot trees (Prúnus armeníaca) in the residential zone of Volgograd. The novelty of the work lies in the study of the dispersed composition of dust particles on the leaves of apricot trees (Prúnus armeníaca) in the residential zone in the city of Volgograd near the construction industry enterprise, me-chanical engineering, leather production and railway transport line in comparison with the conditionally clean (control) zone of the SNT “Orocenets” ”(Sovetsky District, Volgograd) from the standpoint of random functions expressed by integral distribution curves of the mass of particles over their equivalent diameters. As a result of the research, the dispersed composition of dust on the leaves of apricot trees (Prúnus ar-meníaca) in the residential area of Volgograd was revealed. Fine particles were found: PM2.5, PM10 in each of the studied points, which by their values, both in their number and mass fraction, significantly exceed the data on fine dust in a conditionally clean area (control) in the SNT “Oroshanets” (Sovetsky district Volgo-grad), which creates certain environmental risks for local residents. The dispersed analysis of particles from the standpoint of random functions in the future will allow with a sufficiently high degree of accuracy to pre-dict the dust content of urban atmospheric air in the range of monthly and / or seasonal average values compared to the traditional measurement of fine dust concentration in atmospheric air of the urban environ-ment as the maximum single or daily average. At the same time, further studies of dust on the leaves of plants in an urban environment, namely, the study of the density of its sedimentation, will also reveal a group of ur-ban plants that are best suited to retain PM2.5 and PM10 on leaf plates in this region, which can significantly increase the quality of the atmospheric air of the urban environment and be of a recommendatory nature for the state-owned landscaping services of the city of Volgograd when improving the green areas of a megacity.

scholarly journals Impact on Ultrafine Particles Concentration and Turbulent Fluxes of SARS-CoV-2 Lockdown in a Suburban Area in Italy

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 407
Author(s):  
Antonio Donateo ◽  
Adelaide Dinoi ◽  
Gianluca Pappaccogli
Keyword(s):  
Ultrafine Particles ◽  
Particle Number ◽  
Ultrafine Particle ◽  
Turbulent Fluxes ◽  
Number Concentration ◽  
Suburban Area ◽  
Observation Site ◽  
Meteorological Forcing ◽  
Restrictive Measures ◽  
Measurement Area

In order to slow the spread of SARS-CoV-2, governments have implemented several restrictive measures (lockdown, stay-in-place, and quarantine policies). These provisions have drastically changed the routines of residents, altering environmental conditions in the affected areas. In this context, our work analyzes the effects of the reduced emissions during the COVID-19 period on the ultrafine particles number concentration and their turbulent fluxes in a suburban area. COVID-19 restrictions did not significantly reduce anthropogenic related PM10 and PM2.5 levels, with an equal decrement of about 14%. The ultrafine particle number concentration during the lockdown period decreased by 64% in our measurement area, essentially due to the lower traffic activity. The effect of the restriction measures and the reduction of vehicles traffic was predominant in reducing concentration rather than meteorological forcing. During the lockdown in 2020, a decrease of 61% in ultrafine particle positive fluxes can be observed. At the same time, negative fluxes decreased by 59% and our observation site behaved, essentially, as a sink of ultrafine particles. Due to this behavior, we can conclude that the principal particle sources during the lockdown were far away from the measurement site.

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